From c8e2f4e3a327181b29521583770a6f0ff68ca6eb Mon Sep 17 00:00:00 2001
From: Thierry Parmentelat <thierry.parmentelat@inria.fr>
Date: Tue, 17 Mar 2015 17:58:59 +0100
Subject: [PATCH] one layer of polish

---
 system/Completer.py            |  79 +++++----
 system/LocalSubstrate.inria.py |  10 +-
 system/PlcapiUrlScanner.py     |  69 ++++----
 system/TestAuthSfa.py          |  68 ++++----
 system/TestBoxQemu.py          |   4 +-
 system/TestKey.py              |  42 ++---
 system/TestMain.py             |  77 +++++----
 system/TestMapper.py           |  54 +++---
 system/TestNode.py             | 202 ++++++++++++----------
 system/TestPlc.py              | 305 +++++++++++++++++----------------
 system/TestSite.py             |  23 +--
 system/TestSlice.py            | 130 +++++++-------
 system/TestSliceSfa.py         | 110 ++++++------
 system/TestSliver.py           |  52 +++---
 system/TestSsh.py              |  42 ++---
 system/TestUser.py             |  42 ++---
 system/TestUserSfa.py          |  35 ++--
 system/tcptest.py              |  12 +-
 system/utils.py                |  52 +++---
 19 files changed, 725 insertions(+), 683 deletions(-)

diff --git a/system/Completer.py b/system/Completer.py
index 943e9c5..d24af01 100755
--- a/system/Completer.py
+++ b/system/Completer.py
@@ -10,9 +10,9 @@ import utils
 ### of a CompleterTask subclass
 class Completer:
     def __init__ (self, tasks, verbose=True, message=None):
-        self.tasks=tasks
-        self.verbose=verbose
-        self.message="({})".format(message) if message else ""
+        self.tasks = tasks
+        self.verbose = verbose
+        self.message = "({})".format(message) if message else ""
     def run (self, timeout_timedelta, silent_timedelta, period):
         begin = datetime.now()
         timeout = begin+timeout_timedelta
@@ -21,28 +21,30 @@ class Completer:
         graceout = datetime.now()+silent_timedelta
         silent_seconds = silent_timedelta.total_seconds()
         silent_minutes = silent_seconds/60
-        period_seconds=int(period.total_seconds())
+        period_seconds = int(period.total_seconds())
         if self.verbose:
             if timeout_seconds >= 120:
-                utils.header("Completer [%d tasks]: max timeout is %d minutes, "
-                             "silent for %d minutes (period is %s s)"%\
-                             (len(self.tasks), timeout_minutes,
-                              silent_minutes, period_seconds))
+                utils.header("Completer [{} tasks]: max timeout is {} minutes, "
+                             "silent for {} minutes (period is {} s)"\
+                             .format(len(self.tasks), timeout_minutes,
+                                     silent_minutes, period_seconds))
             else:
-                utils.header("Completer [%d tasks]: max timeout is %d seconds, "
-                             "silent for %d seconds (period is %s s)"%\
-                             (len(self.tasks), timeout_seconds,
-                              silent_seconds, period_seconds))
-        tasks=self.tasks
+                utils.header("Completer [{} tasks]: max timeout is {} seconds, "
+                             "silent for {} seconds (period is {} s)"\
+                             .format(len(self.tasks), timeout_seconds,
+                                     silent_seconds, period_seconds))
+        tasks = self.tasks
         while tasks:
-            fine=[]
+            fine = []
             for task in tasks:
-                success=task.run (silent=datetime.now() <= graceout)
-                if success: fine.append(task)
-            for task in fine: tasks.remove(task)
+                success = task.run (silent=datetime.now() <= graceout)
+                if success:
+                    fine.append(task)
+            for task in fine:
+                tasks.remove(task)
             if not tasks:
                 if self.verbose:
-                    duration = datetime.now()-begin
+                    duration = datetime.now() - begin
                     print "total completer {} {}s".format(self.message,
                                                           int(duration.total_seconds()))
                 return True
@@ -51,7 +53,7 @@ class Completer:
                     task.failure_epilogue()
                 return False
             if self.verbose:
-                print '%ds..'%period_seconds,
+                print '{}s..'.format(period_seconds),
             time.sleep(period_seconds)
         # in case we're empty 
         return True
@@ -72,42 +74,47 @@ class Completer:
 
 class CompleterTask:
     def run (self, silent):
-        result=self.actual_run()
+        result = self.actual_run()
         if silent:
             print '+' if result else '.',
             sys.stdout.flush()
         else:
-            print self.message(),"->","OK" if result else "KO"
+            print self.message(), "->", "OK" if result else "KO"
         return result
-    def message (self): return "you-need-to-redefine-message"
-    def failure_epilogue (self): print "you-need-to-redefine-failure_epilogue"
+
+    def message (self):
+        return "you-need-to-redefine-message"
+
+    def failure_epilogue (self):
+        print "you-need-to-redefine-failure_epilogue"
 
 # random result
 class TaskTest (CompleterTask):
-    counter=1
+    counter = 1
     def __init__ (self,max):
         import random
-        self.counter=TaskTest.counter
-        TaskTest.counter+=1
-        self.delay=random.random()*max
-        self.fire=datetime.now()+timedelta(seconds=self.delay)
+        self.counter = TaskTest.counter
+        TaskTest.counter += 1
+        self.delay = random.random()*max
+        self.fire = datetime.now() + timedelta(seconds=self.delay)
     def actual_run(self):
-        return datetime.now()>=self.fire
+        return datetime.now() >= self.fire
     def message (self):
-        return "Task %d - delay was %d s"%(self.counter,self.delay)
+        return "Task {} - delay was {}s".format(self.counter, self.delay)
 
-    def failure_epilogue (self): print "BOTTOM LINE: FAILURE with task (%s)"%self.counter
+    def failure_epilogue (self):
+        print "BOTTOM LINE: FAILURE with task ({})".format(self.counter)
 
 def main ():
     import sys
-    if len(sys.argv)!=6:
+    if len(sys.argv) != 6:
         print "Usage: <command> number_tasks max_random timeout_s silent_s period_s"
         sys.exit(1)
-    [number,max,timeout,silent,period]= [ int(x) for x in sys.argv[1:]]
+    [number, max, timeout, silent, period] = [ int(x) for x in sys.argv[1:]]
     tasks = [ TaskTest(max) for i in range(number)]
-    success=Completer(tasks,verbose=True).run(timedelta(seconds=timeout),
-                                              timedelta(seconds=silent),
-                                              timedelta(seconds=period))
+    success = Completer(tasks,verbose=True).run(timedelta(seconds=timeout),
+                                                timedelta(seconds=silent),
+                                                timedelta(seconds=period))
     print "OVERALL",success
 
 if __name__ == '__main__':
diff --git a/system/LocalSubstrate.inria.py b/system/LocalSubstrate.inria.py
index a4f1359..2767f32 100755
--- a/system/LocalSubstrate.inria.py
+++ b/system/LocalSubstrate.inria.py
@@ -20,9 +20,7 @@ class OnelabSubstrate (Substrate):
 
    # the experimental lxc-based build box
    def build_lxc_boxes_spec (self):
-# velvet needs attention
-#      return [ 'liquid', 'reed', 'velvet' ]
-# reed out of the pool, liquid only used for the last f18 build      
+# liquid only used for the last f18 build      
       return [ 'buzzcocks', 'liquid' ]
 
    # the lxc-capable box for PLCs
@@ -35,7 +33,7 @@ class OnelabSubstrate (Substrate):
 
    # vplc01 to 40
    def vplc_ips (self):
-      return [  ( 'vplc%02d'%i,                 # DNS name
+      return [  ( 'vplc{:02d}'.format(i),       # DNS name
                   'unused')                     # MAC address 
                 for i in range(1,41) ] 
 
@@ -65,8 +63,8 @@ class OnelabSubstrate (Substrate):
 
    # the nodes pool has a MAC address as user-data (3rd elt in tuple)
    def vnode_ips (self):
-      return [ ( 'vnode%02d'%i,                 # DNS name               
-                 '02:34:56:00:00:%02d'%i)       # MAC address
+      return [ ( 'vnode{:02d}'.format(i),            # DNS name               
+                 '02:34:56:00:00:{:02d}'.format(i))  # MAC address
                for i in range(1,21) ] 
    
    # local network settings
diff --git a/system/PlcapiUrlScanner.py b/system/PlcapiUrlScanner.py
index c790bd9..2beef07 100755
--- a/system/PlcapiUrlScanner.py
+++ b/system/PlcapiUrlScanner.py
@@ -13,50 +13,57 @@ class PlcapiUrlScanner:
 
     # turns out the config has an ip but no name..
     def __init__ (self, auth, hostname=None, ip=None, verbose=False):
-        self.auth=auth
+        self.auth = auth
         if not hostname and not ip:
-            raise Exception,"PlcapiUrlScanner needs _some_ input"
+            raise Exception, "PlcapiUrlScanner needs _some_ input"
         if hostname:
             if not ip: 
-                try:    ip=socket.gethostbyname(hostname)
+                try:
+                    ip = socket.gethostbyname(hostname)
                 except: 
-                    hostname="%s.pl.sophia.inria.fr"%hostname
-                    ip=socket.gethostbyname(hostname)
+                    hostname = "{}.pl.sophia.inria.fr".format(hostname)
+                    ip = socket.gethostbyname(hostname)
         else:
-            if not hostname: hostname=socket.gethostbyaddr(ip)[0]
-        self.hostname=hostname
-        self.ip=ip
-        self.verbose=verbose
+            hostname=socket.gethostbyaddr(ip)[0]
+        self.hostname = hostname
+        self.ip = ip
+        self.verbose = verbose
         
-    def try_url (self,url):
+    def try_url (self, url):
         try:
             xmlrpclib.ServerProxy (url, verbose=self.verbose, allow_none=True).GetNodes(self.auth)
-            print 'YES',url
+            print 'YES', url
             return True
         except xmlrpclib.ProtocolError as e:
-            print '... (http error %s)'%e.errcode,url
+            print '... (http error {})'.format(e.errcode), url
             return False
         except Exception as e:
-            print '---',type(e).__name__,url,e
-            if self.verbose: traceback.print_exc()
+            print '---', type(e).__name__, url, e
+            if self.verbose:
+                traceback.print_exc()
             return False
 
     def try_url_required (self, url, required):
-        result=self.try_url(url)
-        if required and not result:     return False
-        else:                           return True
+        result = self.try_url(url)
+        if required and not result:
+            return False
+        else:
+            return True
 
     def scan(self):
-        overall=True
+        overall = True
         for protocol in ['http','https']:
             for dest in [ self.hostname, self.ip ]:
-                for port in [ '',':80',':443']:
-                    for path in ['PLCAPI','PLCAPI/']:
-                        if protocol=='http' and port==':443': continue
-                        if protocol=='https' and port==':80': continue
+                for port in [ '', ':80', ':443']:
+                    for path in ['PLCAPI', 'PLCAPI/']:
+                        if protocol=='http' and port==':443':
+                            continue
+                        if protocol=='https' and port==':80':
+                            continue
                         required = (protocol=='https') and (path=='PLCAPI/')
-                        url="%s://%s%s/%s"%(protocol,dest,port,path)
-                        if not self.try_url_required (url,required): overall=False
+                        url="{}://{}{}/{}".format(protocol, dest, port, path)
+                        if not self.try_url_required (url,required):
+                            overall=False
         return overall
 
 from optparse import OptionParser
@@ -65,15 +72,15 @@ import sys
 auth={'AuthMethod':'password','Username':'root@test.onelab.eu','AuthString':'test++'}
 
 def main ():
-    usage="%prog hostname"
-    parser=OptionParser()
-    parser.add_option("-v","--verbose",dest='verbose',action='store_true',default=False)
-    (options,args)=parser.parse_args()
-    if len(args)!=1:
+    usage = "%prog hostname"
+    parser = OptionParser()
+    parser.add_option("-v", "--verbose", dest='verbose', action='store_true', default=False)
+    (options,args) = parser.parse_args()
+    if len(args) != 1:
         parser.print_help()
         sys.exit(1)
-    hostname=args[0]
-    success=PlcapiUrlScanner (auth=auth, hostname=hostname,verbose=options.verbose).scan()
+    hostname = args[0]
+    success = PlcapiUrlScanner (auth=auth, hostname=hostname,verbose=options.verbose).scan()
     sys.exit(0 if success else -1)
 
 if __name__ == '__main__':
diff --git a/system/TestAuthSfa.py b/system/TestAuthSfa.py
index 6d3d542..2b1ac5f 100644
--- a/system/TestAuthSfa.py
+++ b/system/TestAuthSfa.py
@@ -14,8 +14,8 @@ def slice_sfa_mapper (method):
         # used to map on several slices...
         overall=True
         slice_method = TestSliceSfa.__dict__[method.__name__]
-        slice_spec=self.auth_sfa_spec['slice_spec']
-        test_slice_sfa = TestSliceSfa(self,slice_spec)
+        slice_spec = self.auth_sfa_spec['slice_spec']
+        test_slice_sfa = TestSliceSfa(self, slice_spec)
         if not slice_method(test_slice_sfa, *args, **kwds): overall=False
         return overall
     # restore the doc text
@@ -32,25 +32,25 @@ def user_sfa_mapper (method):
             if not user_method(test_user_sfa, *args, **kwds): overall=False
         return overall
     # restore the doc text
-    actual.__doc__=TestUserSfa.__dict__[method.__name__].__doc__
+    actual.__doc__ = TestUserSfa.__dict__[method.__name__].__doc__
     return actual
 
 
 class TestAuthSfa:
 
-    def __init__ (self,test_plc,auth_sfa_spec):
-	self.test_plc=test_plc
-	self.auth_sfa_spec=auth_sfa_spec
-        self.test_ssh=TestSsh(self.test_plc.test_ssh)
+    def __init__ (self, test_plc, auth_sfa_spec):
+	self.test_plc = test_plc
+	self.auth_sfa_spec = auth_sfa_spec
+        self.test_ssh = TestSsh(self.test_plc.test_ssh)
 #        # shortcuts
-        self.login_base=self.auth_sfa_spec['login_base']
-#        self.piuser=self.auth_sfa_spec['piuser']
-#        self.regularuser=self.auth_sfa_spec['regularuser']
+        self.login_base = self.auth_sfa_spec['login_base']
+#        self.piuser = self.auth_sfa_spec['piuser']
+#        self.regularuser = self.auth_sfa_spec['regularuser']
     
     def rspec_style (self): return self.auth_sfa_spec['rspec_style']
 
     def sfi_path (self):
-        return "/root/sfi/%s"%(self.rspec_style())
+        return "/root/sfi/{}".format(self.rspec_style())
 
     # the hrn for the root authority
     def root_hrn (self):
@@ -58,11 +58,11 @@ class TestAuthSfa:
 
     # the hrn for the auth/site
     def auth_hrn (self):
-        return "%s.%s"%(self.root_hrn(),self.login_base)
+        return "{}.{}".format(self.root_hrn(), self.login_base)
 
     # something in this site (users typically); for use by classes for subobjects
     def obj_hrn (self, name):
-        return "%s.%s"%(self.auth_hrn(),name)
+        return "{}.{}".format(self.auth_hrn(), name)
 
     def regular_user_hrn(self):
         return self.obj_hrn(self.auth_sfa_spec['user_spec']['name'])
@@ -89,30 +89,30 @@ class TestAuthSfa:
                 fileconf=open(file_name,'w')
                 fileconf.write (contents)
                 fileconf.close()
-                utils.header ("(Over)wrote %s"%file_name)
+                utils.header ("(Over)wrote {}".format(file_name))
         #
 	file_name=dir_name + os.sep + 'sfi_config'
         fileconf=open(file_name,'w')
 	SFI_AUTH=self.auth_hrn()
-        fileconf.write ("SFI_AUTH='%s'"%SFI_AUTH)
+        fileconf.write ("SFI_AUTH='{}'".format(SFI_AUTH))
 	fileconf.write('\n')
         # default is to run as a PI
 	SFI_USER=self.obj_hrn(self.auth_sfa_spec['pi_spec']['name'])
-        fileconf.write ("SFI_USER='%s'"%SFI_USER)
+        fileconf.write("SFI_USER='{}'".format(SFI_USER))
 	fileconf.write('\n')
-	SFI_REGISTRY='http://%s:%s/'%(sfa_spec['settings']['SFA_REGISTRY_HOST'],12345)
-        fileconf.write ("SFI_REGISTRY='%s'"%SFI_REGISTRY)
+	SFI_REGISTRY='http://{}:{}/'.format(sfa_spec['settings']['SFA_REGISTRY_HOST'], 12345)
+        fileconf.write("SFI_REGISTRY='{}'".format(SFI_REGISTRY))
 	fileconf.write('\n')
-	SFI_SM='http://%s:%s/'%(sfa_spec['settings']['SFA_SM_HOST'],sfa_spec['sfi-connects-to-port'])
-        fileconf.write ("SFI_SM='%s'"%SFI_SM)
+	SFI_SM='http://{}:{}/'.format(sfa_spec['settings']['SFA_SM_HOST'], sfa_spec['sfi-connects-to-port'])
+        fileconf.write("SFI_SM='{}'".format(SFI_SM))
 	fileconf.write('\n')
         fileconf.close()
-        utils.header ("(Over)wrote %s"%file_name)
+        utils.header ("(Over)wrote {}".format(file_name))
 
     # using sfaadmin to bootstrap
     def sfa_register_site (self, options):
         "bootstrap a site using sfaadmin"
-        command="sfaadmin reg register -t authority -x %s"%self.auth_hrn()
+        command="sfaadmin reg register -t authority -x {}".format(self.auth_hrn())
         return self.test_plc.run_in_guest(command)==0
 
     def sfa_register_pi (self, options):
@@ -122,19 +122,19 @@ class TestAuthSfa:
         pi_mail=pi_spec['email']
         # as installed by sfi_config
         pi_key=os.path.join(self.sfi_path(),self.obj_hrn(pi_spec['name']+'.pub'))
-        command="sfaadmin reg register -t user -x %s --email %s --key %s"%(pi_hrn,pi_mail,pi_key)
+        command="sfaadmin reg register -t user -x {} --email {} --key {}".format(pi_hrn, pi_mail, pi_key)
         if self.test_plc.run_in_guest(command)!=0: return False
-        command="sfaadmin reg update -t authority -x %s --pi %s"%(self.auth_hrn(),pi_hrn)
-        return self.test_plc.run_in_guest(command)==0
+        command="sfaadmin reg update -t authority -x {} --pi {}".format(self.auth_hrn(), pi_hrn)
+        return self.test_plc.run_in_guest(command) == 0
 
     # run as pi
     def sfi_pi (self, command):
         pi_name=self.auth_sfa_spec['pi_spec']['name']
-        return "sfi -d %s -u %s %s"%(self.sfi_path(),self.obj_hrn(pi_name), command,)
+        return "sfi -d {} -u {} {}".format(self.sfi_path(), self.obj_hrn(pi_name), command)
     # the sfi command line option to run as a regular user
     def sfi_user (self, command):
         user_name=self.auth_sfa_spec['user_spec']['name']
-        return "sfi -d %s -u %s %s"%(self.sfi_path(),self.obj_hrn(user_name), command,)
+        return "sfi -d {} -u {} {}".format(self.sfi_path(), self.obj_hrn(user_name), command)
 
     # user management
     @user_sfa_mapper
@@ -146,38 +146,38 @@ class TestAuthSfa:
 
     def sfa_remove_user_from_slice (self, options):
         "remove regular user from slice"
-        command="update -t slice -x %s -r none"%(self.slice_hrn())
+        command="update -t slice -x {} -r none".format(self.slice_hrn())
         # xxx should check result other than visually
         return self.test_plc.run_in_guest(self.sfi_pi(command))==0
 
     def sfa_insert_user_in_slice (self, options):
         "defines regular user as unique user in slice"
-        command="update -t slice -x %s -r %s"%(self.slice_hrn(),self.regular_user_hrn())
+        command="update -t slice -x {} -r {}".format(self.slice_hrn(), self.regular_user_hrn())
         # xxx should check result other than visually
         return self.test_plc.run_in_guest(self.sfi_pi(command))==0
 
     def sfi_list (self, options):
         "run (as regular user) sfi list (on Registry)"
 	return \
-            self.test_plc.run_in_guest(self.sfi_user("list -r %s"%self.root_hrn()))==0 and \
-            self.test_plc.run_in_guest(self.sfi_user("list %s"%(self.auth_hrn())))==0
+            self.test_plc.run_in_guest(self.sfi_user("list -r {}".format(self.root_hrn()))) == 0 and \
+            self.test_plc.run_in_guest(self.sfi_user("list {}".format(self.auth_hrn()))) == 0
 
     def sfi_show_site (self, options):
         "run (as regular user) sfi show (on Registry)"
 	return \
-            self.test_plc.run_in_guest(self.sfi_user("show %s"%(self.auth_hrn())))==0
+            self.test_plc.run_in_guest(self.sfi_user("show {}".format(self.auth_hrn()))) == 0
 
 
     def sfi_show_slice (self, options):
         "run (as PI) sfi show -n <slice> (on Registry)"
         return \
-            self.test_plc.run_in_guest(self.sfi_pi("show -n %s"%self.slice_hrn()))==0
+            self.test_plc.run_in_guest(self.sfi_pi("show -n {}".format(self.slice_hrn()))) == 0
 
     # checks if self.regular_user is found in registry's reg-researchers
     def sfi_show_slice_researchers (self, options):
         "run (as PI) sfi show <slice> -k researcher -k reg-researchers (on Registry)"
         return \
-            self.test_plc.run_in_guest(self.sfi_pi("show %s -k researcher -k reg-researchers"%self.slice_hrn()))==0
+            self.test_plc.run_in_guest(self.sfi_pi("show {} -k researcher -k reg-researchers".format(self.slice_hrn()))) == 0
         
 
     # those are step names exposed as methods of TestPlc, hence the _sfa
diff --git a/system/TestBoxQemu.py b/system/TestBoxQemu.py
index 6d118a1..641a8dc 100644
--- a/system/TestBoxQemu.py
+++ b/system/TestBoxQemu.py
@@ -26,7 +26,7 @@ class TestBoxQemu:
         return self.test_ssh.is_local()
     
     def run_in_buildname (self,command,background=False, dry_run=False):
-        message="On %s: running %s"%(self.hostname(),command)
+        message="On {}: running {}".format(self.hostname(), command)
         if background: message += " &"
         utils.header(message)
         return self.test_ssh.run_in_buildname (command,background, dry_run)
@@ -43,7 +43,7 @@ class TestBoxQemu:
 
     # we need at least one nodename, as template-qemu is not synced on remote testboxes
     def qemu_kill_all(self,nodedir):
-        self.run_in_buildname("%s/qemu-kill-node"%nodedir)
+        self.run_in_buildname("{}/qemu-kill-node".format(nodedir))
         return True
 
     def qemu_list_all(self):
diff --git a/system/TestKey.py b/system/TestKey.py
index 4ff08ff..2f4958d 100644
--- a/system/TestKey.py
+++ b/system/TestKey.py
@@ -7,44 +7,30 @@ from TestSsh import TestSsh
 
 class TestKey:
 
-    def __init__ (self,test_plc,key_spec):
-	self.test_plc=test_plc
-	self.key_spec=key_spec
-        self.test_ssh=TestSsh(self.test_plc.test_ssh)
+    def __init__ (self, test_plc, key_spec):
+	self.test_plc = test_plc
+	self.key_spec = key_spec
+        self.test_ssh = TestSsh(self.test_plc.test_ssh)
         
     def name(self):
         return self.key_spec['key_name']
 
     def publicpath(self):
-        return "keys/%s.pub"%(self.name())
+        return "keys/{}.pub".format(self.name())
     def privatepath(self):
-        return "keys/%s.rsa"%(self.name())
+        return "keys/{}.rsa".format(self.name())
 
-#Not tested yet, don't know if needed
-#    def store_remote_key(self,hostname):
-#        pub=self.publicpath()
-#        priv=self.privatepath()
-#        utils.header("Storing key %s in %s into %s "%(self.name(),pub,hostname))
-#        dir=os.path.dirname(pub)
-#        self.test_ssh.run("mkdir %s"%dir)
-#        self.test_ssh.run("cat %s >> %s"%(self.key_spec['key_fields']['key'],pub))
-#        self.test_ssh.run("cat %s >> %s"%(self.key_spec['private'],priv))
-#        self.test_ssh.run("chmod %s 0400"%priv)
-#        self.test_ssh.run("chmod %s 0444"%pub)
-            
     def store_key(self):
-        pub=self.publicpath()
-        priv=self.privatepath()
-        utils.header("Storing key %s in %s"%(self.name(),pub))
-        dir=os.path.dirname(pub)
+        pub = self.publicpath()
+        priv = self.privatepath()
+        utils.header("Storing key {} in {}".format(self.name(), pub))
+        dir = os.path.dirname(pub)
         if not os.path.isdir(dir):
             os.mkdir(dir)
-        f=open(pub,"w")
-        f.write(self.key_spec['key_fields']['key'])
-        f.close()
-        f=open(priv,"w")
-        f.write(self.key_spec['private'])
-        f.close()
+        with open(pub,"w") as f:
+            f.write(self.key_spec['key_fields']['key'])
+        with open(priv,"w") as f:
+            f.write(self.key_spec['private'])
         os.chmod(priv,0400)
         os.chmod(pub,0444)
             
diff --git a/system/TestMain.py b/system/TestMain.py
index 01bf6cd..0518e1b 100755
--- a/system/TestMain.py
+++ b/system/TestMain.py
@@ -40,7 +40,7 @@ class Step:
             try:
                 self.substeps = sequences[self.internal()]
             except Exception,e:
-                print "macro step %s not found in macros.py (%s) - exiting" % (self.display(),e)
+                print "macro step {} not found in macros.py ({}) - exiting".format(self.display(),e)
                 raise
 
     def print_doc (self, level=0):
@@ -124,8 +124,8 @@ class TestMain:
             print self.steps_message
         else:
             # steps mentioned on the command line
-            if self.options.args:
-                scopes = [("Argument steps",self.options.args)]
+            if self.options.steps:
+                scopes = [("Argument steps",self.options.steps)]
             else:
                 scopes = [("Default steps", TestPlc.default_steps)]
                 if self.options.all_steps:
@@ -149,14 +149,15 @@ class TestMain:
 arch-rpms-url defaults to the last value used, as stored in arg-arch-rpms-url,
    no default
 config defaults to the last value used, as stored in arg-config,
-   or %r
-ips_vnode, ips_vplc and ips_qemu defaults to the last value used, as stored in arg-ips-{bplc,vplc,bnode,vnode},
+   or {}
+ips_vnode, ips_vplc and ips_qemu defaults to the last value used, 
+   as stored in arg-ips-{{bplc,vplc,bnode,vnode}},
    default is to use IP scanning
 steps refer to a method in TestPlc or to a step_* module
 
 run with -l to see a list of available steps
 ===
-"""%(TestMain.default_config)
+""".format(TestMain.default_config)
 
         parser = ArgumentParser(usage = usage)
         parser.add_argument("-u", "--url", action="store",  dest="arch_rpms_url", 
@@ -253,7 +254,7 @@ run with -l to see a list of available steps
                         parsed = [x.strip() for x in parsed]
                     else:               # strings and booleans
                         if len(parsed) != 1:
-                            print "%s - error when parsing %s" % (sys.argv[1],path)
+                            print "{} - error when parsing {}".format(sys.argv[1], path)
                             sys.exit(1)
                         parsed = parsed[0].strip()
                         if is_bool:
@@ -264,7 +265,7 @@ run with -l to see a list of available steps
                         setattr(self.options, recname, default)
                     else:
                         print "Cannot determine", recname
-                        print "Run %s --help for help" % sys.argv[0]                        
+                        print "Run {} --help for help".format(sys.argv[0])
                         sys.exit(1)
 
             # save for next run
@@ -275,7 +276,7 @@ run with -l to see a list of available steps
             else:                       # strings and booleans - just call str()
                 fsave.write(str(getattr(self.options, recname)) + "\n")
             fsave.close()
-#            utils.header('Saved %s into %s'%(recname,filename))
+#            utils.header('Saved {} into {}'.format(recname, filename))
 
             # lists need be reversed
             # I suspect this is useful for the various pools but for config, it's painful
@@ -283,7 +284,7 @@ run with -l to see a list of available steps
                 getattr(self.options, recname).reverse()
 
             if self.options.verbose:
-                utils.header('* Using %s = %s' % (recname, getattr(self.options, recname)))
+                utils.header('* Using {} = {}'.format(recname, getattr(self.options, recname)))
 
         # hack : if sfa is not among the published rpms, skip these tests
         TestPlc.check_whether_build_has_sfa(self.options.arch_rpms_url)
@@ -341,7 +342,7 @@ run with -l to see a list of available steps
                 all_plc_specs = m.config(all_plc_specs, self.options)
             except :
                 traceback.print_exc()
-                print 'Cannot load config %s -- ignored' % modulename
+                print 'Cannot load config {} -- ignored'.format(modulename)
                 raise
 
         # provision on local substrate
@@ -350,18 +351,18 @@ run with -l to see a list of available steps
         # remember substrate IP address(es) for next run
         ips_bplc_file = open('arg-ips-bplc', 'w')
         for plc_spec in all_plc_specs:
-            ips_bplc_file.write("%s\n" % plc_spec['host_box'])
+            ips_bplc_file.write("{}\n".format(plc_spec['host_box']))
         ips_bplc_file.close()
         ips_vplc_file = open('arg-ips-vplc', 'w')
         for plc_spec in all_plc_specs:
-            ips_vplc_file.write("%s\n" % plc_spec['settings']['PLC_API_HOST'])
+            ips_vplc_file.write("{}\n".format(plc_spec['settings']['PLC_API_HOST']))
         ips_vplc_file.close()
         # ditto for nodes
         ips_bnode_file = open('arg-ips-bnode', 'w')
         for plc_spec in all_plc_specs:
             for site_spec in plc_spec['sites']:
                 for node_spec in site_spec['nodes']:
-                    ips_bnode_file.write("%s\n" % node_spec['host_box'])
+                    ips_bnode_file.write("{}\n".format(node_spec['host_box']))
         ips_bnode_file.close()
         ips_vnode_file = open('arg-ips-vnode','w')
         for plc_spec in all_plc_specs:
@@ -369,7 +370,7 @@ run with -l to see a list of available steps
                 for node_spec in site_spec['nodes']:
                     # back to normal (unqualified) form
                     stripped = node_spec['node_fields']['hostname'].split('.')[0]
-                    ips_vnode_file.write("%s\n" % stripped)
+                    ips_vnode_file.write("{}\n".format(stripped))
         ips_vnode_file.close()
 
         # build a TestPlc object from the result, passing options
@@ -418,7 +419,7 @@ run with -l to see a list of available steps
                         cross = True
                     all_step_infos.append ( (substep, method, force, cross, qualifier, ) )
             except :
-                utils.header("********** FAILED step %s (NOT FOUND) -- won't be run" % step)
+                utils.header("********** FAILED step {} (NOT FOUND) -- won't be run".format(step))
                 traceback.print_exc()
                 overall_result = 'FAILURE'
             
@@ -435,8 +436,8 @@ run with -l to see a list of available steps
 
         # do all steps on all plcs
         TIME_FORMAT = "%H-%M-%S"
-        TRACE_FORMAT = "TRACE: %(plc_counter)d %(begin)s->%(seconds)ss=%(duration)s " + \
-                       "status=%(status)s step=%(stepname)s plc=%(plcname)s force=%(force)s\n"
+        TRACE_FORMAT = "TRACE: {plc_counter:d} {begin}->{seconds}s={duration}s " + \
+                       "status={status} step={stepname} plc={plcname} force={force}\n"
         for stepname, method, force, cross, qualifier in all_step_infos:
             plc_counter = 0
             for spec, plc_obj in all_plcs:
@@ -456,12 +457,12 @@ run with -l to see a list of available steps
                     if self.options.interactive:
                         prompting = True
                         while prompting:
-                            msg="%d Run step %s on %s [r](un)/d(ry_run)/p(roceed)/s(kip)/q(uit) ? " % \
-                                (plc_counter,stepname,plcname)
+                            msg="{:d} Run step {} on {} [r](un)/d(ry_run)/p(roceed)/s(kip)/q(uit) ? "\
+                                .format(plc_counter, stepname, plcname)
                             answer = raw_input(msg).strip().lower() or "r"
                             answer = answer[0]
                             if answer in ['s','n']:     # skip/no/next
-                                print '%s on %s skipped' % (stepname, plcname)
+                                print '{} on {} skipped'.format(stepname, plcname)
                                 prompting = False
                                 skip_step = True
                             elif answer in ['q','b']:   # quit/bye
@@ -491,9 +492,9 @@ run with -l to see a list of available steps
                     try:
                         force_msg = ""
                         if force and spec['failed_step']:
-                            force_msg=" (forced after %s has failed)" % spec['failed_step']
-                        utils.header("********** %d RUNNING step %s%s on plc %s" % \
-                                     (plc_counter, stepname, force_msg, plcname))
+                            force_msg=" (forced after {} has failed)".format(spec['failed_step'])
+                        utils.header("********** {:d} RUNNING step {}{} on plc {}"\
+                                     .format(plc_counter, stepname, force_msg, plcname))
                         if not cross:
                             step_result = method(plc_obj)
                         else:
@@ -507,42 +508,42 @@ run with -l to see a list of available steps
                                 # do not overwrite if FAILURE
                                 if overall_result == 'SUCCESS': 
                                     overall_result = 'IGNORED'
-                            utils.header('********** %d IGNORED (%s) step %s on %s' % \
-                                         (plc_counter, msg, stepname, plcname))
-                            status="%s[I]" % msg
+                            utils.header('********** {} IGNORED ({}) step {} on {}'\
+                                         .format(plc_counter, msg, stepname, plcname))
+                            status="{}[I]".format(msg)
                         elif step_result:
-                            utils.header('********** %d SUCCESSFUL step %s on %s' % \
-                                         (plc_counter, stepname, plcname))
+                            utils.header('********** {:d} SUCCESSFUL step {} on {}'\
+                                         .format(plc_counter, stepname, plcname))
                             status = "OK"
                         else:
                             overall_result = 'FAILURE'
                             spec['failed_step'] = stepname
-                            utils.header('********** %d FAILED step %s on %s (discarded from further steps)' % \
-                                         (plc_counter, stepname, plcname))
+                            utils.header('********** {:d} FAILED step {} on {} (discarded from further steps)'\
+                                         .format(plc_counter, stepname, plcname))
                             status = "KO"
                     except:
                         overall_result = 'FAILURE'
                         spec['failed_step'] = stepname
                         traceback.print_exc()
-                        utils.header ('********** %d FAILED (exception) step %s on %s (discarded from further steps)' % \
-                                      (plc_counter, stepname, plcname))
+                        utils.header ('********** {} FAILED (exception) step {} on {} (discarded from further steps)'\
+                                      .format(plc_counter, stepname, plcname))
                         status = "KO"
 
                 # do not run, just display it's skipped
                 else:
-                    why = "has failed %s" % spec['failed_step']
-                    utils.header("********** %d SKIPPED Step %s on %s (%s)" % \
-                                 (plc_counter, stepname, plcname, why))
+                    why = "has failed {}".format(spec['failed_step'])
+                    utils.header("********** {} SKIPPED Step {} on {} ({})"\
+                                 .format(plc_counter, stepname, plcname, why))
                     status = "UNDEF"
                 if not self.options.dry_run:
                     delay = datetime.now()-beg_time
                     seconds = int(delay.total_seconds())
                     duration = str(delay)
                     # always do this on stdout
-                    print TRACE_FORMAT % locals()
+                    print TRACE_FORMAT.format(**locals())
                     # duplicate on trace_file if provided
                     if self.options.trace_file:
-                        trace.write(TRACE_FORMAT % locals())
+                        trace.write(TRACE_FORMAT.format(**locals()))
                         trace.flush()
 
         if self.options.trace_file and not self.options.dry_run:
diff --git a/system/TestMapper.py b/system/TestMapper.py
index 7d0547f..9a8ea67 100644
--- a/system/TestMapper.py
+++ b/system/TestMapper.py
@@ -13,73 +13,75 @@ import utils
 
 class TestMapper:
 
-    def __init__ (self,plcs,options):
-        self.plcs=plcs
-        self.options=options
+    def __init__(self,plcs,options):
+        self.plcs = plcs
+        self.options = options
 
     @staticmethod
-    def plc_name (plc):
+    def plc_name(plc):
         return plc['name']
 
     @staticmethod
-    def node_name (node):
+    def node_name(node):
         return node['name']
 
-    def node_names (self):
-        result=[]
+    def node_names(self):
+        result = []
         for plc in self.plcs:
             for site in plc['sites']:
                 for node in site['nodes']:
                     result.append(node['name'])
         return result
 
-    def apply_first_map (self, type, name, obj, maplist):
+    def apply_first_map(self, type, name, obj, maplist):
         for (map_pattern,rename_dict) in maplist:
             if utils.match (name,map_pattern):
                 if self.options.verbose:
-                    utils.header("TestMapper/%s : applying rules '%s' on %s"%(type,map_pattern,name))
+                    utils.header("TestMapper/{} : applying rules '{}' on {}"\
+                                 .format(type, map_pattern, name))
                 for (k,v) in rename_dict.iteritems():
                     # apply : separator
-                    path=k.split(':')
+                    path = k.split(':')
                     # step down but last step in path
-                    o=obj
+                    o = obj
                     for step in path[:-1]:
                         if not o.has_key(step):
-                            o[step]={}
+                            o[step] = {}
                             if self.options.verbose:
-                                utils.header ("WARNING : created step %s in path %s on %s %s"%(
-                                        step,path,type,name))
-                        o=o[step]
+                                utils.header ("WARNING : created step {} in path {} on {} {}"\
+                                              .format(step,path,type,name))
+                        o = o[step]
                     # last step is the one for side-effect
-                    step=path[-1]
+                    step = path[-1]
                     if self.options.verbose:
                         if not o.has_key(step):
-                            utils.header ("WARNING : inserting key %s for path %s on %s %s"%(
-                                    step,path,type,name))
+                            utils.header ("WARNING : inserting key {} for path {} on {} {}"\
+                                          .format(step, path, type, name))
                     # apply formatting if '%s' found in the value
                     if v is None:
                         if self.options.verbose: print "TestMapper WARNING - None value - ignored, key=",k
                         continue
-                    if v.find('%s')>=0:
-                        v=v%obj[k]
+                    if v.find('%s') >= 0:
+                        v = v % obj[k]
                     if self.options.verbose:
-                        print("TestMapper, rewriting %s: %s into %s"%(name,k,v))
-                    o[step]=v
+                        print("TestMapper, rewriting {}: {} into {}"\
+                              .format(name, k, v))
+                    o[step] = v
                 # only apply first rule
                 return
 
-    def map (self,mapper):
+    def map(self, mapper):
 
         plc_maps  = mapper.get('plc',[])
         node_maps = mapper.get('node',[])
 
         for plc in self.plcs:
-            name=TestMapper.plc_name(plc)
-            self.apply_first_map ('plc',name,plc,plc_maps)
+            name = TestMapper.plc_name(plc)
+            self.apply_first_map('plc', name, plc, plc_maps)
 
             for site in plc['sites']:
                 for node in site['nodes']:
                     nodename = TestMapper.node_name(node)
-                    self.apply_first_map('node',nodename,node,node_maps)
+                    self.apply_first_map('node', nodename, node, node_maps)
 
         return self.plcs
diff --git a/system/TestNode.py b/system/TestNode.py
index 6bf40ad..cdbf071 100644
--- a/system/TestNode.py
+++ b/system/TestNode.py
@@ -10,35 +10,39 @@ from TestSsh import TestSsh
 from Completer import CompleterTask
 
 class CompleterTaskNodeSsh (CompleterTask):
-    def __init__ (self, hostname, qemuname, local_key, command=None, boot_state="boot", expected=True, dry_run=False):
-        self.hostname=hostname
-        self.qemuname=qemuname
-        self.boot_state=boot_state
-        self.local_key=local_key
-        self.command=command if command is not None else "hostname;uname -a"
-        self.expected=expected
+    def __init__ (self, hostname, qemuname, local_key, command=None,
+                  boot_state="boot", expected=True, dry_run=False):
+        self.hostname = hostname
+        self.qemuname = qemuname
+        self.boot_state = boot_state
+        self.local_key = local_key
+        self.command = command if command is not None else "hostname;uname -a"
+        self.expected = expected
         self.dry_run = dry_run
-        self.test_ssh =  TestSsh (self.hostname,key=self.local_key)
+        self.test_ssh =  TestSsh (self.hostname, key=self.local_key)
     def run (self, silent):
         command = self.test_ssh.actual_command(self.command)
         retcod = utils.system (command, silent=silent, dry_run=self.dry_run)
-        if self.expected:       return retcod == 0
-        else:                   return retcod != 0
+        if self.expected:
+            return retcod == 0
+        else:
+            return retcod != 0
     def failure_epilogue (self):
-        print "Cannot reach %s in %s mode"%(self.hostname, self.boot_state)
+        print "Cannot reach {} in {} mode".format(self.hostname, self.boot_state)
 
 class TestNode:
 
-    def __init__ (self,test_plc,test_site,node_spec):
-	self.test_plc=test_plc
-	self.test_site=test_site
-	self.node_spec=node_spec
+    def __init__ (self, test_plc, test_site, node_spec):
+	self.test_plc = test_plc
+	self.test_site = test_site
+	self.node_spec = node_spec
         
     def name(self):
         return self.node_spec['node_fields']['hostname']
     
     def dry_run (self):
         return self.test_plc.options.dry_run
+
     @staticmethod
     def is_qemu_model (model):
         return model.find("qemu") >= 0
@@ -56,9 +60,9 @@ class TestNode:
         
     def nodedir (self):
         if self.is_qemu():
-            return "qemu-%s"%self.name()
+            return "qemu-{}".format(self.name())
         else:
-            return "real-%s"%self.name()
+            return "real-{}".format(self.name())
 
     # this returns a hostname
     def host_box (self):
@@ -84,12 +88,12 @@ class TestNode:
         user_spec = self.test_site.locate_user(ownername)
         test_user = TestUser(self.test_plc,self.test_site,user_spec)
         userauth = test_user.auth()
-        utils.header("node %s created by user %s"%(self.name(),test_user.name()))
-        rootauth=self.test_plc.auth_root()
-        server = self.test_plc.apiserver
-        node_id=server.AddNode(userauth,
-                               self.test_site.site_spec['site_fields']['login_base'],
-                               self.node_spec['node_fields'])
+        utils.header("node {} created by user {}".format(self.name(), test_user.name()))
+        rootauth = self.test_plc.auth_root()
+        server  =  self.test_plc.apiserver
+        node_id = server.AddNode(userauth,
+                                 self.test_site.site_spec['site_fields']['login_base'],
+                                 self.node_spec['node_fields'])
         server.SetNodePlainBootstrapfs(userauth,
                                        self.node_spec['node_fields']['hostname'],
                                        'YES')
@@ -107,8 +111,8 @@ class TestNode:
             server.UpdateNode (userauth, self.name(), self.node_spec['node_fields_nint'])
             interface_id = server.AddInterface (userauth, self.name(),self.node_spec['interface_fields_nint'])
             server.AddIpAddress (userauth, interface_id, self.node_spec['ipaddress_fields'])
-            route_fields=self.node_spec['route_fields']
-            route_fields['interface_id']=interface_id
+            route_fields = self.node_spec['route_fields']
+            route_fields['interface_id'] = interface_id
             server.AddRoute (userauth, node_id, self.node_spec['route_fields'])
             pass
         # populate network interfaces - others
@@ -119,7 +123,7 @@ class TestNode:
                     for (attribute,value) in interface['settings'].iteritems():
                         # locate node network
                         interface = server.GetInterfaces(userauth,{'ip':interface['interface_fields']['ip']})[0]
-                        interface_id=interface['interface_id']
+                        interface_id = interface['interface_id']
                         # locate or create node network attribute type
                         try:
                             interface_tagtype = server.GetTagTypes(userauth,{'name':attribute})[0]
@@ -137,33 +141,34 @@ class TestNode:
             test_user = TestUser(self.test_plc,self.test_site,user_spec)
             auth = test_user.auth()
         except:
-            auth=self.test_plc.auth_root()
+            auth = self.test_plc.auth_root()
         self.test_plc.apiserver.DeleteNode(auth,self.name())
 
     # Do most of the stuff locally - will be pushed on host_box - *not* the plc - later if needed
     def qemu_local_init(self):
         "all nodes : init a clean local directory for holding node-dep stuff like iso image..."
-        utils.system("rm -rf %s"%self.nodedir())
-        utils.system("mkdir %s"%self.nodedir())
+        utils.system("rm -rf {}".format(self.nodedir()))
+        utils.system("mkdir {}".format(self.nodedir()))
         if not self.is_qemu():
             return True
-        return utils.system("rsync -v -a --exclude .svn template-qemu/ %s/"%self.nodedir())==0
+        return utils.system("rsync -v -a --exclude .svn template-qemu/ {}/"\
+                            .format(self.nodedir())) == 0
 
     def bootcd(self):
         "all nodes: invoke GetBootMedium and store result locally"
-        utils.header("Calling GetBootMedium for %s"%self.name())
+        utils.header("Calling GetBootMedium for {}".format(self.name()))
         options = []
         if self.is_qemu():
             options.append('serial')
             options.append('no-hangcheck')
             options.append('systemd-debug')
-        encoded=self.test_plc.apiserver.GetBootMedium(self.test_plc.auth_root(), 
-                                                      self.name(), 'node-iso', '', options)
+        encoded = self.test_plc.apiserver.GetBootMedium(self.test_plc.auth_root(), 
+                                                        self.name(), 'node-iso', '', options)
         if (encoded == ''):
             raise Exception, 'GetBootmedium failed'
 
-        filename="%s/%s.iso"%(self.nodedir(),self.name())
-        utils.header('Storing boot medium into %s'%filename)
+        filename = "{}/{}.iso".format(self.nodedir(), self.name())
+        utils.header('Storing boot medium into {}'.format(filename))
         if self.dry_run():
             print "Dry_run: skipped writing of iso image"
             return True
@@ -194,7 +199,7 @@ class TestNode:
         if self.dry_run():
             print "Dry_run: skipped getting current node state"
             return True
-        state=self.test_plc.apiserver.GetNodes(self.test_plc.auth_root(), self.name(), ['boot_state'])[0]['boot_state']
+        state = self.test_plc.apiserver.GetNodes(self.test_plc.auth_root(), self.name(), ['boot_state'])[0]['boot_state']
         print self.name(),':',state
         return True
     
@@ -202,28 +207,28 @@ class TestNode:
         "all nodes: compute qemu config qemu.conf and store it locally"
         if not self.is_qemu():
             return
-        mac=self.node_spec['interface_fields']['mac']
-        hostname=self.node_spec['node_fields']['hostname']
-        ip=self.node_spec['interface_fields']['ip']
-        auth=self.test_plc.auth_root()
-        target_arch=self.test_plc.apiserver.GetPlcRelease(auth)['build']['target-arch']
-        conf_filename="%s/qemu.conf"%(self.nodedir())
+        mac = self.node_spec['interface_fields']['mac']
+        hostname = self.node_spec['node_fields']['hostname']
+        ip = self.node_spec['interface_fields']['ip']
+        auth = self.test_plc.auth_root()
+        target_arch = self.test_plc.apiserver.GetPlcRelease(auth)['build']['target-arch']
+        conf_filename = "{}/qemu.conf".format(self.nodedir())
         if self.dry_run():
             print "dry_run: skipped actual storage of qemu.conf"
             return True
-        utils.header('Storing qemu config for %s in %s'%(self.name(),conf_filename))
-        file=open(conf_filename,'w')
-        file.write('MACADDR=%s\n'%mac)
-        file.write('NODE_ISO=%s.iso\n'%self.name())
-        file.write('HOSTNAME=%s\n'%hostname)
-        file.write('IP=%s\n'%ip)
-        file.write('TARGET_ARCH=%s\n'%target_arch)
-        file.close()
+        utils.header('Storing qemu config for {} in {}'.format(self.name(), conf_filename))
+        with open(conf_filename,'w') as f:
+            file.write('MACADDR={}\n'.format(mac))
+            file.write('NODE_ISO={}.iso\n'.format(self.name()))
+            file.write('HOSTNAME={}\n'.format(hostname))
+            file.write('IP={}\n'.format(ip))
+            file.write('TARGET_ARCH={}\n'.format(target_arch))
         return True
 
     def qemu_clean (self):
-        utils.header("Cleaning up qemu for host %s on box %s"%(self.name(),self.test_box().hostname()))
-        dry_run=self.dry_run()
+        utils.header("Cleaning up qemu for host {} on box {}"\
+                     .format(self.name(),self.test_box().hostname()))
+        dry_run = self.dry_run()
         self.test_box().rmdir(self.nodedir(), dry_run=dry_run)
         return True
 
@@ -232,40 +237,47 @@ class TestNode:
         # if relevant, push the qemu area onto the host box
         if self.test_box().is_local():
             return True
-        dry_run=self.dry_run()
-        utils.header ("Cleaning any former sequel of %s on %s"%(self.name(),self.host_box()))
-        utils.header ("Transferring configuration files for node %s onto %s"%(self.name(),self.host_box()))
-        return self.test_box().copy(self.nodedir(),recursive=True,dry_run=dry_run)==0
+        dry_run = self.dry_run()
+        utils.header ("Cleaning any former sequel of {} on {}"\
+                      .format(self.name(), self.host_box()))
+        utils.header ("Transferring configuration files for node {} onto {}"\
+                      .format(self.name(), self.host_box()))
+        return self.test_box().copy(self.nodedir(), recursive=True, dry_run=dry_run) == 0
             
     def qemu_start (self):
         "all nodes: start the qemu instance (also runs qemu-bridge-init start)"
-        model=self.node_spec['node_fields']['model']
+        model = self.node_spec['node_fields']['model']
         #starting the Qemu nodes before 
         if self.is_qemu():
             self.start_qemu()
         else:
-            utils.header("TestNode.qemu_start : %s model %s taken as real node"%(self.name(),model))
+            utils.header("TestNode.qemu_start : {} model {} taken as real node"\
+                         .format(self.name(), model))
         return True
 
     def qemu_timestamp (self):
         "all nodes: start the qemu instance (also runs qemu-bridge-init start)"
         test_box = self.test_box()
-        test_box.run_in_buildname("mkdir -p %s"%self.nodedir(), dry_run=self.dry_run())
-        now=int(time.time())
-        return test_box.run_in_buildname("echo %d > %s/timestamp"%(now,self.nodedir()), dry_run=self.dry_run())==0
+        test_box.run_in_buildname("mkdir -p {}".format(self.nodedir()), dry_run=self.dry_run())
+        now = int(time.time())
+        return test_box.run_in_buildname("echo {:d} > {}/timestamp"\
+                                         .format(now, self.nodedir()), dry_run=self.dry_run()) == 0
 
     def start_qemu (self):
         test_box = self.test_box()
-        utils.header("Starting qemu node %s on %s"%(self.name(),test_box.hostname()))
+        utils.header("Starting qemu node {} on {}".format(self.name(), test_box.hostname()))
 
-        test_box.run_in_buildname("%s/qemu-bridge-init start >> %s/log.txt"%(self.nodedir(),self.nodedir()),
+        test_box.run_in_buildname("{}/qemu-bridge-init start >> {}/log.txt"\
+                                  .format(self.nodedir(), self.nodedir()),
                                   dry_run=self.dry_run())
         # kick it off in background, as it would otherwise hang
-        test_box.run_in_buildname("%s/qemu-start-node 2>&1 >> %s/log.txt"%(self.nodedir(),self.nodedir()))
+        test_box.run_in_buildname("{}/qemu-start-node 2>&1 >> {}/log.txt"\
+                                  .format(self.nodedir(), self.nodedir()))
 
     def list_qemu (self):
-        utils.header("Listing qemu for host %s on box %s"%(self.name(),self.test_box().hostname()))
-        command="%s/qemu-kill-node -l %s"%(self.nodedir(),self.name())
+        utils.header("Listing qemu for host {} on box {}"\
+                     .format(self.name(), self.test_box().hostname()))
+        command = "{}/qemu-kill-node -l {}".format(self.nodedir(), self.name())
         self.test_box().run_in_buildname(command, dry_run=self.dry_run())
         return True
 
@@ -273,16 +285,17 @@ class TestNode:
         #Prepare the log file before killing the nodes
         test_box = self.test_box()
         # kill the right processes 
-        utils.header("Stopping qemu for node %s on box %s"%(self.name(),self.test_box().hostname()))
-        command="%s/qemu-kill-node %s"%(self.nodedir(),self.name())
+        utils.header("Stopping qemu for node {} on box {}"\
+                     .format(self.name(), self.test_box().hostname()))
+        command = "{}/qemu-kill-node {}".format(self.nodedir(),self.name())
         self.test_box().run_in_buildname(command, dry_run=self.dry_run())
         return True
 
     def gather_qemu_logs (self):
         if not self.is_qemu():
             return True
-        remote_log="%s/log.txt"%self.nodedir()
-        local_log="logs/node.qemu.%s.txt"%self.name()
+        remote_log = "{}/log.txt".format(self.nodedir())
+        local_log = "logs/node.qemu.{}.txt".format(self.name())
         self.test_box().test_ssh.fetch(remote_log,local_log,dry_run=self.dry_run())
 
     def keys_clear_known_hosts (self):
@@ -292,17 +305,17 @@ class TestNode:
 
     def create_test_ssh(self):
         # get the plc's keys for entering the node
-        vservername=self.test_plc.vservername
+        vservername = self.test_plc.vservername
 ###        # assuming we've run testplc.fetch_keys()
-###        key = "keys/%(vservername)s.rsa"%locals()
+###        key = "keys/{vservername}.rsa".format(**locals())
         # fetch_keys doesn't grab the root key anymore
         key = "keys/key_admin.rsa"
         return TestSsh(self.name(), buildname=self.buildname(), key=key)
 
     def check_hooks (self):
         extensions = [ 'py','pl','sh' ]
-        path='hooks/node'
-        scripts=utils.locate_hooks_scripts ('node '+self.name(), path,extensions)
+        path = 'hooks/node'
+        scripts = utils.locate_hooks_scripts ('node '+self.name(), path,extensions)
         overall = True
         for script in scripts:
             if not self.check_hooks_script (script):
@@ -311,38 +324,41 @@ class TestNode:
 
     def check_hooks_script (self,local_script):
         # push the script on the node's root context
-        script_name=os.path.basename(local_script)
-        utils.header ("NODE hook %s (%s)"%(script_name,self.name()))
-        test_ssh=self.create_test_ssh()
+        script_name = os.path.basename(local_script)
+        utils.header ("NODE hook {} ({})".format(script_name, self.name()))
+        test_ssh = self.create_test_ssh()
         test_ssh.copy_home(local_script)
         if test_ssh.run("./"+script_name) != 0:
-            utils.header ("WARNING: node hooks check script %s FAILED (ignored)"%script_name)
+            utils.header ("WARNING: node hooks check script {} FAILED (ignored)"\
+                          .format(script_name))
             #return False
             return True
         else:
-            utils.header ("SUCCESS: node hook %s OK"%script_name)
+            utils.header ("SUCCESS: node hook {} OK".format(script_name))
             return True
 
     def has_libvirt (self):
-        test_ssh=self.create_test_ssh()
-        return test_ssh.run ("rpm -q --quiet libvirt-client")==0
+        test_ssh = self.create_test_ssh()
+        return test_ssh.run ("rpm -q --quiet libvirt-client") == 0
 
-    def _check_system_slice (self, slicename,dry_run=False):
-        sitename=self.test_plc.plc_spec['settings']['PLC_SLICE_PREFIX']
-        vservername="%s_%s"%(sitename,slicename)
-        test_ssh=self.create_test_ssh()
+    def _check_system_slice (self, slicename, dry_run=False):
+        sitename = self.test_plc.plc_spec['settings']['PLC_SLICE_PREFIX']
+        vservername = "{}_{}".format(sitename, slicename)
+        test_ssh = self.create_test_ssh()
         if self.has_libvirt():
-            utils.header("Checking system slice %s using virsh"%slicename)
-            return test_ssh.run("virsh --connect lxc:// list | grep -q ' %s '"%vservername,
-                                dry_run=dry_run)==0
+            utils.header("Checking system slice {} using virsh".format(slicename))
+            return test_ssh.run("virsh --connect lxc:// list | grep -q ' {} '".format(vservername),
+                                dry_run = dry_run) == 0
         else:
-            (retcod,output)=utils.output_of(test_ssh.actual_command("cat /vservers/%s/etc/slicefamily 2> /dev/null")%vservername)
+            (retcod,output) = \
+                    utils.output_of(test_ssh.actual_command("cat /vservers/{}/etc/slicefamily 2> /dev/null")\
+                                    .format(vservername))
             # get last line only as ssh pollutes the output
-            slicefamily=output.split("\n")[-1]
-            utils.header("Found slicefamily '%s'for slice %s"%(slicefamily,slicename))
+            slicefamily = output.split("\n")[-1]
+            utils.header("Found slicefamily '{}'for slice {}".format(slicefamily,slicename))
             if retcod != 0: 
                 return False
-            utils.header("Checking system slice %s using vserver-stat"%slicename)
-            return test_ssh.run("vserver-stat | grep %s"%vservername,dry_run=dry_run)==0
+            utils.header("Checking system slice {} using vserver-stat".format(slicename))
+            return test_ssh.run("vserver-stat | grep {}".format(vservername), dry_run=dry_run) == 0
         
         
diff --git a/system/TestPlc.py b/system/TestPlc.py
index a60f619..9788085 100644
--- a/system/TestPlc.py
+++ b/system/TestPlc.py
@@ -30,7 +30,7 @@ has_sfa_cache_filename="sfa-cache"
 # step methods must take (self) and return a boolean (options is a member of the class)
 
 def standby(minutes, dry_run):
-    utils.header('Entering StandBy for %d mn'%minutes)
+    utils.header('Entering StandBy for {:d} mn'.format(minutes))
     if dry_run:
         print 'dry_run'
     else:
@@ -92,7 +92,7 @@ def ignore_result(method):
         ref_name = method.__name__.replace('_ignore', '').replace('force_', '')
         ref_method = TestPlc.__dict__[ref_name]
         result = ref_method(self)
-        print "Actual (but ignored) result for %(ref_name)s is %(result)s" % locals()
+        print "Actual (but ignored) result for {ref_name} is {result}".format(**locals())
         return Ignored(result)
     name = method.__name__.replace('_ignore', '').replace('force_', '')
     ignoring.__name__ = name
@@ -228,12 +228,12 @@ class TestPlc:
     def _has_sfa_cached(rpms_url):
         if os.path.isfile(has_sfa_cache_filename):
             cached = file(has_sfa_cache_filename).read() == "yes"
-            utils.header("build provides SFA (cached):%s" % cached)
+            utils.header("build provides SFA (cached):{}".format(cached))
             return cached
         # warning, we're now building 'sface' so let's be a bit more picky
         # full builds are expected to return with 0 here
         utils.header("Checking if build provides SFA package...")
-        retcod = os.system("curl --silent %s/ | grep -q sfa-"%rpms_url) == 0
+        retcod = os.system("curl --silent {}/ | grep -q sfa-".format(rpms_url)) == 0
         encoded = 'yes' if retcod else 'no'
         with open(has_sfa_cache_filename,'w')as out:
             out.write(encoded)
@@ -259,7 +259,7 @@ class TestPlc:
 	self.test_ssh = TestSsh(self.plc_spec['host_box'], self.options.buildname)
         self.vserverip = plc_spec['vserverip']
         self.vservername = plc_spec['vservername']
-        self.url = "https://%s:443/PLCAPI/" % plc_spec['vserverip']
+        self.url = "https://{}:443/PLCAPI/".format(plc_spec['vserverip'])
 	self.apiserver = TestApiserver(self.url, options.dry_run)
         (self.ssh_node_boot_timeout, self.ssh_node_boot_silent) = plc_spec['ssh_node_boot_timers']
         (self.ssh_node_debug_timeout, self.ssh_node_debug_silent) = plc_spec['ssh_node_debug_timers']
@@ -269,7 +269,7 @@ class TestPlc:
 
     def name(self):
         name = self.plc_spec['name']
-        return "%s.%s" % (name,self.vservername)
+        return "{}.{}".format(name,self.vservername)
 
     def hostname(self):
         return self.plc_spec['host_box']
@@ -308,27 +308,27 @@ class TestPlc:
     def host_to_guest(self, command):
         vservername = self.vservername
         personality = self.options.personality
-        raw = "%(personality)s virsh -c lxc:/// lxc-enter-namespace %(vservername)s" % locals()
+        raw = "{personality} virsh -c lxc:/// lxc-enter-namespace {vservername}".format(**locals())
         # f14 still needs some extra help
         if self.options.fcdistro == 'f14':
-            raw +=" -- /usr/bin/env PATH=/bin:/sbin:/usr/bin:/usr/sbin %(command)s" % locals()
+            raw +=" -- /usr/bin/env PATH=/bin:/sbin:/usr/bin:/usr/sbin {command}".format(**locals())
         else:
-            raw +=" -- /usr/bin/env %(command)s" % locals()
+            raw +=" -- /usr/bin/env {command}".format(**locals())
         return raw
     
     # this /vservers thing is legacy...
     def vm_root_in_host(self):
-        return "/vservers/%s/" % (self.vservername)
+        return "/vservers/{}/".format(self.vservername)
 
     def vm_timestamp_path(self):
-        return "/vservers/%s/%s.timestamp" % (self.vservername,self.vservername)
+        return "/vservers/{}/{}.timestamp".format(self.vservername, self.vservername)
 
     #start/stop the vserver
     def start_guest_in_host(self):
-        return "virsh -c lxc:/// start %s" % (self.vservername)
+        return "virsh -c lxc:/// start {}".format(self.vservername)
     
     def stop_guest_in_host(self):
-        return "virsh -c lxc:/// destroy %s" % (self.vservername)
+        return "virsh -c lxc:/// destroy {}".format(self.vservername)
     
     # xxx quick n dirty
     def run_in_guest_piped(self,local,remote):
@@ -338,13 +338,13 @@ class TestPlc:
     def yum_check_installed(self, rpms):
         if isinstance(rpms, list): 
             rpms=" ".join(rpms)
-        return self.run_in_guest("rpm -q %s"%rpms) == 0
+        return self.run_in_guest("rpm -q {}".format(rpms)) == 0
         
     # does a yum install in the vs, ignore yum retcod, check with rpm
     def yum_install(self, rpms):
         if isinstance(rpms, list): 
             rpms=" ".join(rpms)
-        self.run_in_guest("yum -y install %s" % rpms)
+        self.run_in_guest("yum -y install {}".format(rpms))
         # yum-complete-transaction comes with yum-utils, that is in vtest.pkgs
         self.run_in_guest("yum-complete-transaction -y")
         return self.yum_check_installed(rpms)
@@ -362,27 +362,27 @@ class TestPlc:
                 return site
             if site['site_fields']['login_base'] == sitename:
                 return site
-        raise Exception,"Cannot locate site %s" % sitename
+        raise Exception,"Cannot locate site {}".format(sitename)
         
     def locate_node(self, nodename):
         for site in self.plc_spec['sites']:
             for node in site['nodes']:
                 if node['name'] == nodename:
                     return site, node
-        raise Exception, "Cannot locate node %s" % nodename
+        raise Exception, "Cannot locate node {}".format(nodename)
         
     def locate_hostname(self, hostname):
         for site in self.plc_spec['sites']:
             for node in site['nodes']:
                 if node['node_fields']['hostname'] == hostname:
                     return(site, node)
-        raise Exception,"Cannot locate hostname %s" % hostname
+        raise Exception,"Cannot locate hostname {}".format(hostname)
         
     def locate_key(self, key_name):
         for key in self.plc_spec['keys']:
             if key['key_name'] == key_name:
                 return key
-        raise Exception,"Cannot locate key %s" % key_name
+        raise Exception,"Cannot locate key {}".format(key_name)
 
     def locate_private_key_from_key_names(self, key_names):
         # locate the first avail. key
@@ -403,7 +403,7 @@ class TestPlc:
         for slice in self.plc_spec['slices']:
             if slice['slice_fields']['name'] == slicename:
                 return slice
-        raise Exception,"Cannot locate slice %s" % slicename
+        raise Exception,"Cannot locate slice {}".format(slicename)
 
     def all_sliver_objs(self):
         result = []
@@ -521,20 +521,20 @@ class TestPlc:
         "print cut'n paste-able stuff to export env variables to your shell"
         # guess local domain from hostname
         if TestPlc.exported_id > 1: 
-            print "export GUESTHOSTNAME%d=%s" % (TestPlc.exported_id, self.plc_spec['vservername'])
+            print "export GUESTHOSTNAME{:d}={}".format(TestPlc.exported_id, self.plc_spec['vservername'])
             return True
         TestPlc.exported_id += 1
         domain = socket.gethostname().split('.',1)[1]
-        fqdn   = "%s.%s" % (self.plc_spec['host_box'], domain)
-        print "export BUILD=%s" % self.options.buildname
-        print "export PLCHOSTLXC=%s" % fqdn
-        print "export GUESTNAME=%s" % self.plc_spec['vservername']
+        fqdn   = "{}.{}".format(self.plc_spec['host_box'], domain)
+        print "export BUILD={}".format(self.options.buildname)
+        print "export PLCHOSTLXC={}".format(fqdn)
+        print "export GUESTNAME={}".format(self.plc_spec['vservername'])
         vplcname = self.plc_spec['vservername'].split('-')[-1]
-        print "export GUESTHOSTNAME=%s.%s"%(vplcname, domain)
+        print "export GUESTHOSTNAME={}.{}".format(vplcname, domain)
         # find hostname of first node
         hostname, qemubox = self.all_node_infos()[0]
-        print "export KVMHOST=%s.%s" % (qemubox, domain)
-        print "export NODE=%s" % (hostname)
+        print "export KVMHOST={}.{}".format(qemubox, domain)
+        print "export NODE={}".format(hostname)
         return True
 
     # entry point
@@ -616,7 +616,7 @@ class TestPlc:
                 print '+       ',k,v
 
     def display_node_spec(self, node):
-        print "+           node=%s host_box=%s" % (node['name'],node['host_box']),
+        print "+           node={} host_box={}".format(node['name'], node['host_box']),
         print "hostname=", node['node_fields']['hostname'],
         print "ip=", node['interface_fields']['ip']
         if self.options.verbose:
@@ -631,17 +631,17 @@ class TestPlc:
     def display_mapping_plc(plc_spec):
         print '+ MyPLC',plc_spec['name']
         # WARNING this would not be right for lxc-based PLC's - should be harmless though
-        print '+\tvserver address = root@%s:/vservers/%s' % (plc_spec['host_box'], plc_spec['vservername'])
-        print '+\tIP = %s/%s' % (plc_spec['settings']['PLC_API_HOST'], plc_spec['vserverip'])
+        print '+\tvserver address = root@{}:/vservers/{}'.format(plc_spec['host_box'], plc_spec['vservername'])
+        print '+\tIP = {}/{}'.format(plc_spec['settings']['PLC_API_HOST'], plc_spec['vserverip'])
         for site_spec in plc_spec['sites']:
             for node_spec in site_spec['nodes']:
                 TestPlc.display_mapping_node(node_spec)
 
     @staticmethod
     def display_mapping_node(node_spec):
-        print '+   NODE %s' % (node_spec['name'])
-        print '+\tqemu box %s' % node_spec['host_box']
-        print '+\thostname=%s' % node_spec['node_fields']['hostname']
+        print '+   NODE {}'.format(node_spec['name'])
+        print '+\tqemu box {}'.format(node_spec['host_box'])
+        print '+\thostname={}'.format(node_spec['node_fields']['hostname'])
 
     # write a timestamp in /vservers/<>.timestamp
     # cannot be inside the vserver, that causes vserver .. build to cough
@@ -652,18 +652,18 @@ class TestPlc:
         # a first approx. is to store the timestamp close to the VM root like vs does
         stamp_path = self.vm_timestamp_path()
         stamp_dir = os.path.dirname(stamp_path)
-        utils.system(self.test_ssh.actual_command("mkdir -p %s" % stamp_dir))
-        return utils.system(self.test_ssh.actual_command("echo %d > %s" % (now, stamp_path))) == 0
+        utils.system(self.test_ssh.actual_command("mkdir -p {}".format(stamp_dir)))
+        return utils.system(self.test_ssh.actual_command("echo {:d} > {}".format(now, stamp_path))) == 0
         
     # this is called inconditionnally at the beginning of the test sequence 
     # just in case this is a rerun, so if the vm is not running it's fine
     def plcvm_delete(self):
         "vserver delete the test myplc"
         stamp_path = self.vm_timestamp_path()
-        self.run_in_host("rm -f %s" % stamp_path)
-        self.run_in_host("virsh -c lxc:// destroy %s" % self.vservername)
-        self.run_in_host("virsh -c lxc:// undefine %s" % self.vservername)
-        self.run_in_host("rm -fr /vservers/%s" % self.vservername)
+        self.run_in_host("rm -f {}".format(stamp_path))
+        self.run_in_host("virsh -c lxc:// destroy {}".format(self.vservername))
+        self.run_in_host("virsh -c lxc:// undefine {}".format(self.vservername))
+        self.run_in_host("rm -fr /vservers/{}".format(self.vservername))
         return True
 
     ### install
@@ -696,19 +696,19 @@ class TestPlc:
         script = "lbuild-initvm.sh"
         script_options = ""
         # pass the vbuild-nightly options to [lv]test-initvm
-        script_options += " -p %s" % self.options.personality
-        script_options += " -d %s" % self.options.pldistro
-        script_options += " -f %s" % self.options.fcdistro
-        script_options += " -r %s" % repo_url
+        script_options += " -p {}".format(self.options.personality)
+        script_options += " -d {}".format(self.options.pldistro)
+        script_options += " -f {}".format(self.options.fcdistro)
+        script_options += " -r {}".format(repo_url)
         vserver_name = self.vservername
         try:
             vserver_hostname = socket.gethostbyaddr(self.vserverip)[0]
-            script_options += " -n %s" % vserver_hostname
+            script_options += " -n {}".format(vserver_hostname)
         except:
-            print "Cannot reverse lookup %s" % self.vserverip
+            print "Cannot reverse lookup {}".format(self.vserverip)
             print "This is considered fatal, as this might pollute the test results"
             return False
-        create_vserver="%(build_dir)s/%(script)s %(script_options)s %(vserver_name)s" % locals()
+        create_vserver="{build_dir}/{script} {script_options} {vserver_name}".format(**locals())
         return self.run_in_host(create_vserver) == 0
 
     ### install_rpm 
@@ -725,14 +725,14 @@ class TestPlc:
         elif self.options.personality == "linux64":
             arch = "x86_64"
         else:
-            raise Exception, "Unsupported personality %r"%self.options.personality
-        nodefamily = "%s-%s-%s" % (self.options.pldistro, self.options.fcdistro, arch)
+            raise Exception, "Unsupported personality {}".format(self.options.personality)
+        nodefamily = "{}-{}-{}".format(self.options.pldistro, self.options.fcdistro, arch)
 
         pkgs_list=[]
-        pkgs_list.append("slicerepo-%s" % nodefamily)
+        pkgs_list.append("slicerepo-{}".format(nodefamily))
         pkgs_list.append("myplc")
-        pkgs_list.append("noderepo-%s" % nodefamily)
-        pkgs_list.append("nodeimage-%s-plain" % nodefamily)
+        pkgs_list.append("noderepo-{}".format(nodefamily))
+        pkgs_list.append("nodeimage-{}-plain".format(nodefamily))
         pkgs_string=" ".join(pkgs_list)
         return self.yum_install(pkgs_list)
 
@@ -744,15 +744,15 @@ class TestPlc:
     ### 
     def plc_configure(self):
         "run plc-config-tty"
-        tmpname = '%s.plc-config-tty' % self.name()
+        tmpname = '{}.plc-config-tty'.format(self.name())
         with open(tmpname,'w') as fileconf:
             for (var,value) in self.plc_spec['settings'].iteritems():
-                fileconf.write('e %s\n%s\n'%(var,value))
+                fileconf.write('e {}\n{}\n'.format(var, value))
             fileconf.write('w\n')
             fileconf.write('q\n')
-        utils.system('cat %s' % tmpname)
-        self.run_in_guest_piped('cat %s' % tmpname, 'plc-config-tty')
-        utils.system('rm %s' % tmpname)
+        utils.system('cat {}'.format(tmpname))
+        self.run_in_guest_piped('cat {}'.format(tmpname), 'plc-config-tty')
+        utils.system('rm {}'.format(tmpname))
         return True
 
 # f14 is a bit odd in this respect, although this worked fine in guests up to f18
@@ -770,13 +770,13 @@ class TestPlc:
     def start_stop_service(self, service, start_or_stop):
         "utility to start/stop a service with the special trick for f14"
         if self.options.fcdistro != 'f14':
-            return self.run_in_guest("service %s %s" % (service, start_or_stop)) == 0
+            return self.run_in_guest("service {} {}".format(service, start_or_stop)) == 0
         else:
             # patch /sbin/service so it does not reset environment
             self.run_in_guest('sed -i -e \\"s,env -i,env,\\" /sbin/service')
             # this is because our own scripts in turn call service 
-            return self.run_in_guest("SYSTEMCTL_SKIP_REDIRECT=true service %s %s" % \
-                                     (service, start_or_stop)) == 0
+            return self.run_in_guest("SYSTEMCTL_SKIP_REDIRECT=true service {} {}"\
+                                     .format(service, start_or_stop)) == 0
 
     def plc_start(self):
         "service plc start"
@@ -820,8 +820,8 @@ class TestPlc:
         overall = True
         prefix = 'debug_ssh_key'
         for ext in ['pub', 'rsa'] :
-            src = "%(vm_root)s/etc/planetlab/%(prefix)s.%(ext)s" % locals()
-            dst = "keys/%(vservername)s-debug.%(ext)s" % locals()
+            src = "{vm_root}/etc/planetlab/{prefix}.{ext}".format(**locals())
+            dst = "keys/{vservername}-debug.{ext}".format(**locals())
             if self.test_ssh.fetch(src, dst) != 0:
                 overall=False
         return overall
@@ -838,13 +838,13 @@ class TestPlc:
         for site_spec in self.plc_spec['sites']:
             test_site = TestSite(self,site_spec)
             if (action != "add"):
-                utils.header("Deleting site %s in %s" % (test_site.name(), self.name()))
+                utils.header("Deleting site {} in {}".format(test_site.name(), self.name()))
                 test_site.delete_site()
                 # deleted with the site
                 #test_site.delete_users()
                 continue
             else:
-                utils.header("Creating site %s & users in %s" % (test_site.name(), self.name()))
+                utils.header("Creating site {} & users in {}".format(test_site.name(), self.name()))
                 test_site.create_site()
                 test_site.create_users()
         return True
@@ -873,15 +873,15 @@ class TestPlc:
         for site_spec in self.plc_spec['sites']:
             test_site = TestSite(self, site_spec)
             if action != "add":
-                utils.header("Deleting nodes in site %s" % test_site.name())
+                utils.header("Deleting nodes in site {}".format(test_site.name()))
                 for node_spec in site_spec['nodes']:
                     test_node = TestNode(self, test_site, node_spec)
-                    utils.header("Deleting %s" % test_node.name())
+                    utils.header("Deleting {}".format(test_node.name()))
                     test_node.delete_node()
             else:
-                utils.header("Creating nodes for site %s in %s" % (test_site.name(), self.name()))
+                utils.header("Creating nodes for site {} in {}".format(test_site.name(), self.name()))
                 for node_spec in site_spec['nodes']:
-                    utils.pprint('Creating node %s' % node_spec, node_spec)
+                    utils.pprint('Creating node {}'.format(node_spec), node_spec)
                     test_node = TestNode(self, test_site, node_spec)
                     test_node.create_node()
         return True
@@ -929,20 +929,20 @@ class TestPlc:
             lease_addition = self.apiserver.AddLeases(self.auth_root(), nodes, lease_spec['slice'],
                                                       lease_spec['t_from'],lease_spec['t_until'])
             if lease_addition['errors']:
-                utils.header("Cannot create leases, %s"%lease_addition['errors'])
+                utils.header("Cannot create leases, {}".format(lease_addition['errors']))
                 ok = False
             else:
-                utils.header('Leases on nodes %r for %s from %d (%s) until %d (%s)' % \
-                              (nodes, lease_spec['slice'],
-                               lease_spec['t_from'],  TestPlc.timestamp_printable(lease_spec['t_from']),
-                               lease_spec['t_until'], TestPlc.timestamp_printable(lease_spec['t_until'])))
+                utils.header('Leases on nodes {} for {} from {:d} ({}) until {:d} ({})'\
+                             .format(nodes, lease_spec['slice'],
+                                     lease_spec['t_from'],  TestPlc.timestamp_printable(lease_spec['t_from']),
+                                     lease_spec['t_until'], TestPlc.timestamp_printable(lease_spec['t_until'])))
                 
         return ok
 
     def delete_leases(self):
         "remove all leases in the myplc side"
         lease_ids = [ l['lease_id'] for l in self.apiserver.GetLeases(self.auth_root())]
-        utils.header("Cleaning leases %r" % lease_ids)
+        utils.header("Cleaning leases {}".format(lease_ids))
         self.apiserver.DeleteLeases(self.auth_root(), lease_ids)
         return True
 
@@ -953,10 +953,10 @@ class TestPlc:
         for l in leases:
             current = l['t_until'] >= now
             if self.options.verbose or current:
-                utils.header("%s %s from %s until %s" % \
-                             (l['hostname'], l['name'],
-                              TestPlc.timestamp_printable(l['t_from']), 
-                              TestPlc.timestamp_printable(l['t_until'])))
+                utils.header("{} {} from {} until {}"\
+                             .format(l['hostname'], l['name'],
+                                     TestPlc.timestamp_printable(l['t_from']), 
+                                     TestPlc.timestamp_printable(l['t_until'])))
         return True
 
     # create nodegroups if needed, and populate
@@ -988,7 +988,7 @@ class TestPlc:
                 else:
                     tag_type_id = self.apiserver.AddTagType(auth,
                                                             {'tagname' : nodegroupname,
-                                                             'description' : 'for nodegroup %s' % nodegroupname,
+                                                             'description' : 'for nodegroup {}'.format(nodegroupname),
                                                              'category' : 'test'})
                 print 'located tag (type)', nodegroupname, 'as', tag_type_id
                 # create nodegroup
@@ -1076,16 +1076,16 @@ class TestPlc:
                 except:
                     return False
             def message(self):
-                return "CompleterTaskBootState with node %s" % self.hostname
+                return "CompleterTaskBootState with node {}".format(self.hostname)
             def failure_epilogue(self):
-                print "node %s in state %s - expected %s" %\
-                    (self.hostname, self.last_boot_state, target_boot_state)
+                print "node {} in state {} - expected {}"\
+                    .format(self.hostname, self.last_boot_state, target_boot_state)
                 
         timeout = timedelta(minutes=timeout_minutes)
         graceout = timedelta(minutes=silent_minutes)
         period   = timedelta(seconds=period_seconds)
         # the nodes that haven't checked yet - start with a full list and shrink over time
-        utils.header("checking nodes boot state (expected %s)" % target_boot_state)
+        utils.header("checking nodes boot state (expected {})".format(target_boot_state))
         tasks = [ CompleterTaskBootState(self,hostname) \
                       for (hostname,_) in self.all_node_infos() ]
         message = 'check_boot_state={}'.format(target_boot_state)
@@ -1105,10 +1105,10 @@ class TestPlc:
             def __init__(self, hostname):
                 self.hostname = hostname
             def run(self, silent):
-                command="ping -c 1 -w 1 %s >& /dev/null" % self.hostname
+                command="ping -c 1 -w 1 {} >& /dev/null".format(self.hostname)
                 return utils.system(command, silent=silent) == 0
             def failure_epilogue(self):
-                print "Cannot ping node with name %s" % self.hostname
+                print "Cannot ping node with name {}".format(self.hostname)
         timeout = timedelta(seconds = timeout_seconds)
         graceout = timeout
         period = timedelta(seconds = period_seconds)
@@ -1130,12 +1130,12 @@ class TestPlc:
         if debug: 
             message = "debug"
             completer_message = 'ssh_node_debug'
-            local_key = "keys/%(vservername)s-debug.rsa" % locals()
+            local_key = "keys/{vservername}-debug.rsa".format(**locals())
         else: 
             message = "boot"
             completer_message = 'ssh_node_boot'
 	    local_key = "keys/key_admin.rsa"
-        utils.header("checking ssh access to nodes (expected in %s mode)" % message)
+        utils.header("checking ssh access to nodes (expected in {} mode)".format(message))
         node_infos = self.all_node_infos()
         tasks = [ CompleterTaskNodeSsh(nodename, qemuname, local_key,
                                         boot_state=message, dry_run=self.options.dry_run) \
@@ -1194,10 +1194,10 @@ class TestPlc:
             def actual_run(self):
                 return self.test_sliver.check_initscript_stamp(self.stamp)
             def message(self):
-                return "initscript checker for %s" % self.test_sliver.name()
+                return "initscript checker for {}".format(self.test_sliver.name())
             def failure_epilogue(self):
-                print "initscript stamp %s not found in sliver %s"%\
-                    (self.stamp, self.test_sliver.name())
+                print "initscript stamp {} not found in sliver {}"\
+                    .format(self.stamp, self.test_sliver.name())
             
         tasks = []
         for slice_spec in self.plc_spec['slices']:
@@ -1224,7 +1224,7 @@ class TestPlc:
     def initscripts(self):
         "create initscripts with PLCAPI"
         for initscript in self.plc_spec['initscripts']:
-            utils.pprint('Adding Initscript in plc %s' % self.plc_spec['name'], initscript)
+            utils.pprint('Adding Initscript in plc {}'.format(self.plc_spec['name']), initscript)
             self.apiserver.AddInitScript(self.auth_root(), initscript['initscript_fields'])
         return True
 
@@ -1232,7 +1232,7 @@ class TestPlc:
         "delete initscripts with PLCAPI"
         for initscript in self.plc_spec['initscripts']:
             initscript_name = initscript['initscript_fields']['name']
-            print('Attempting to delete %s in plc %s' % (initscript_name, self.plc_spec['name']))
+            print('Attempting to delete {} in plc {}'.format(initscript_name, self.plc_spec['name']))
             try:
                 self.apiserver.DeleteInitScript(self.auth_root(), initscript_name)
                 print initscript_name, 'deleted'
@@ -1306,11 +1306,11 @@ class TestPlc:
 
     def _speed_up_slices(self, p, r):
         # create the template on the server-side 
-        template = "%s.nodemanager" % self.name()
+        template = "{}.nodemanager".format(self.name())
         with open(template,"w") as template_file:
-            template_file.write('OPTIONS="-p %s -r %s -d"\n'%(p,r))
+            template_file.write('OPTIONS="-p {} -r {} -d"\n'.format(p, r))
         in_vm = "/var/www/html/PlanetLabConf/nodemanager"
-        remote = "%s/%s" % (self.vm_root_in_host(), in_vm)
+        remote = "{}/{}".format(self.vm_root_in_host(), in_vm)
         self.test_ssh.copy_abs(template, remote)
         # Add a conf file
         if not self.apiserver.GetConfFiles(self.auth_root(),
@@ -1323,11 +1323,11 @@ class TestPlc:
 
     def debug_nodemanager(self):
         "sets verbose mode for nodemanager, and speeds up cycle even more (needs speed_up_slices first)"
-        template = "%s.nodemanager" % self.name()
+        template = "{}.nodemanager".format(self.name())
         with open(template,"w") as template_file:
             template_file.write('OPTIONS="-p 10 -r 6 -v -d"\n')
         in_vm = "/var/www/html/PlanetLabConf/nodemanager"
-        remote = "%s/%s" % (self.vm_root_in_host(), in_vm)
+        remote = "{}/{}".format(self.vm_root_in_host(), in_vm)
         self.test_ssh.copy_abs(template, remote)
         return True
 
@@ -1344,7 +1344,7 @@ class TestPlc:
                 return plc.locate_sliver_obj(nodename, slicename)
             except:
                 pass
-        raise Exception, "Cannot locate sliver %s@%s among all PLCs" % (nodename, slicename)
+        raise Exception, "Cannot locate sliver {}@{} among all PLCs".format(nodename, slicename)
 
     # implement this one as a cross step so that we can take advantage of different nodes
     # in multi-plcs mode
@@ -1363,9 +1363,9 @@ class TestPlc:
             def actual_run(self):
                 return self.test_sliver.check_tcp_ready(port = 9999)
             def message(self):
-                return "network ready checker for %s" % self.test_sliver.name()
+                return "network ready checker for {}".format(self.test_sliver.name())
             def failure_epilogue(self):
-                print "could not bind port from sliver %s" % self.test_sliver.name()
+                print "could not bind port from sliver {}".format(self.test_sliver.name())
 
         sliver_specs = {}
         tasks = []
@@ -1374,10 +1374,10 @@ class TestPlc:
             # locate the TestSliver instances involved, and cache them in the spec instance
             spec['s_sliver'] = self.locate_sliver_obj_cross(spec['server_node'], spec['server_slice'], other_plcs)
             spec['c_sliver'] = self.locate_sliver_obj_cross(spec['client_node'], spec['client_slice'], other_plcs)
-            message = "Will check TCP between s=%s and c=%s" % \
-                      (spec['s_sliver'].name(), spec['c_sliver'].name())
+            message = "Will check TCP between s={} and c={}"\
+                      .format(spec['s_sliver'].name(), spec['c_sliver'].name())
             if 'client_connect' in spec:
-                message += " (using %s)" % spec['client_connect']
+                message += " (using {})".format(spec['client_connect'])
             utils.header(message)
             # we need to check network presence in both slivers, but also
             # avoid to insert a sliver several times
@@ -1434,9 +1434,9 @@ class TestPlc:
             def actual_run(self): 
                 return self.test_node._check_system_slice(slicename, dry_run=self.dry_run)
             def message(self): 
-                return "System slice %s @ %s" % (slicename, self.test_node.name())
+                return "System slice {} @ {}".format(slicename, self.test_node.name())
             def failure_epilogue(self): 
-                print "COULD not find system slice %s @ %s"%(slicename, self.test_node.name())
+                print "COULD not find system slice {} @ {}".format(slicename, self.test_node.name())
         timeout = timedelta(minutes=timeout_minutes)
         silent  = timedelta(0)
         period  = timedelta(seconds=period_seconds)
@@ -1448,7 +1448,7 @@ class TestPlc:
         "runs PLCAPI stress test, that checks Add/Update/Delete on all types - preserves contents"
         # install the stress-test in the plc image
         location = "/usr/share/plc_api/plcsh_stress_test.py"
-        remote = "%s/%s" % (self.vm_root_in_host(), location)
+        remote = "{}/{}".format(self.vm_root_in_host(), location)
         self.test_ssh.copy_abs("plcsh_stress_test.py", remote)
         command = location
         command += " -- --check"
@@ -1503,16 +1503,17 @@ class TestPlc:
         utils.header("********** Regular yum failed - special workaround in place, 2nd chance")
         code, cached_rpm_path = \
                 utils.output_of(self.actual_command_in_guest('find /var/cache/yum -name sfa-client\*.rpm'))
-        utils.header("rpm_path=<<%s>>" % rpm_path)
+        utils.header("rpm_path=<<{}>>".format(rpm_path))
         # just for checking 
-        self.run_in_guest("rpm -i %s" % cached_rpm_path)
+        self.run_in_guest("rpm -i {}".format(cached_rpm_path))
         return self.yum_check_installed("sfa-client")
 
     def sfa_dbclean(self):
         "thoroughly wipes off the SFA database"
         return self.run_in_guest("sfaadmin reg nuke") == 0 or \
             self.run_in_guest("sfa-nuke.py") == 0 or \
-            self.run_in_guest("sfa-nuke-plc.py") == 0
+            self.run_in_guest("sfa-nuke-plc.py") == 0 or \
+            self.run_in_guest("sfaadmin registry nuke") == 0             
 
     def sfa_fsclean(self):
         "cleanup /etc/sfa/trusted_roots and /var/lib/sfa"
@@ -1529,7 +1530,7 @@ class TestPlc:
             try:
                 self.apiserver.DeleteSite(self.auth_root(),login_base)
             except:
-                print "Site %s already absent from PLC db"%login_base
+                print "Site {} already absent from PLC db".format(login_base)
 
             for spec_name in ['pi_spec','user_spec']:
                 user_spec = auth_sfa_spec[spec_name]
@@ -1538,7 +1539,7 @@ class TestPlc:
                     self.apiserver.DeletePerson(self.auth_root(),username)
                 except: 
                     # this in fact is expected as sites delete their members
-                    #print "User %s already absent from PLC db"%username
+                    #print "User {} already absent from PLC db".format(username)
                     pass
 
         print "REMEMBER TO RUN sfa_import AGAIN"
@@ -1575,28 +1576,28 @@ class TestPlc:
 
     ###
     def confdir(self):
-        dirname = "conf.%s" % self.plc_spec['name']
+        dirname = "conf.{}".format(self.plc_spec['name'])
         if not os.path.isdir(dirname):
-            utils.system("mkdir -p %s" % dirname)
+            utils.system("mkdir -p {}".format(dirname))
         if not os.path.isdir(dirname):
-            raise Exception,"Cannot create config dir for plc %s" % self.name()
+            raise Exception,"Cannot create config dir for plc {}".format(self.name())
         return dirname
 
     def conffile(self, filename):
-        return "%s/%s" % (self.confdir(),filename)
+        return "{}/{}".format(self.confdir(), filename)
     def confsubdir(self, dirname, clean, dry_run=False):
-        subdirname = "%s/%s" % (self.confdir(),dirname)
+        subdirname = "{}/{}".format(self.confdir(), dirname)
         if clean:
-            utils.system("rm -rf %s" % subdirname)
+            utils.system("rm -rf {}".format(subdirname))
         if not os.path.isdir(subdirname): 
-            utils.system("mkdir -p %s" % subdirname)
+            utils.system("mkdir -p {}".format(subdirname))
         if not dry_run and not os.path.isdir(subdirname):
-            raise "Cannot create config subdir %s for plc %s" % (dirname,self.name())
+            raise "Cannot create config subdir {} for plc {}".format(dirname, self.name())
         return subdirname
         
     def conffile_clean(self, filename):
         filename=self.conffile(filename)
-        return utils.system("rm -rf %s" % filename)==0
+        return utils.system("rm -rf {}".format(filename))==0
     
     ###
     def sfa_configure(self):
@@ -1604,22 +1605,22 @@ class TestPlc:
         tmpname = self.conffile("sfa-config-tty")
         with open(tmpname,'w') as fileconf:
             for (var,value) in self.plc_spec['sfa']['settings'].iteritems():
-                fileconf.write('e %s\n%s\n'%(var,value))
+                fileconf.write('e {}\n{}\n'.format(var, value))
             fileconf.write('w\n')
             fileconf.write('R\n')
             fileconf.write('q\n')
-        utils.system('cat %s' % tmpname)
-        self.run_in_guest_piped('cat %s' % tmpname, 'sfa-config-tty')
+        utils.system('cat {}'.format(tmpname))
+        self.run_in_guest_piped('cat {}'.format(tmpname), 'sfa-config-tty')
         return True
 
     def aggregate_xml_line(self):
         port = self.plc_spec['sfa']['neighbours-port']
-        return '<aggregate addr="%s" hrn="%s" port="%r"/>' % \
-            (self.vserverip, self.plc_spec['sfa']['settings']['SFA_REGISTRY_ROOT_AUTH'], port)
+        return '<aggregate addr="{}" hrn="{}" port="{}"/>'\
+            .format(self.vserverip, self.plc_spec['sfa']['settings']['SFA_REGISTRY_ROOT_AUTH'], port)
 
     def registry_xml_line(self):
-        return '<registry addr="%s" hrn="%s" port="12345"/>' % \
-            (self.vserverip, self.plc_spec['sfa']['settings']['SFA_REGISTRY_ROOT_AUTH'])
+        return '<registry addr="{}" hrn="{}" port="12345"/>'\
+            .format(self.vserverip, self.plc_spec['sfa']['settings']['SFA_REGISTRY_ROOT_AUTH'])
 
 
     # a cross step that takes all other plcs in argument
@@ -1630,18 +1631,18 @@ class TestPlc:
             return True
         agg_fname = self.conffile("agg.xml")
         with open(agg_fname,"w") as out:
-            out.write("<aggregates>%s</aggregates>\n" % \
-                      " ".join([ plc.aggregate_xml_line() for plc in other_plcs ]))
-        utils.header("(Over)wrote %s" % agg_fname)
+            out.write("<aggregates>{}</aggregates>\n"\
+                      .format(" ".join([ plc.aggregate_xml_line() for plc in other_plcs ])))
+        utils.header("(Over)wrote {}".format(agg_fname))
         reg_fname=self.conffile("reg.xml")
         with open(reg_fname,"w") as out:
-            out.write("<registries>%s</registries>\n" % \
-                      " ".join([ plc.registry_xml_line() for plc in other_plcs ]))
-        utils.header("(Over)wrote %s" % reg_fname)
+            out.write("<registries>{}</registries>\n"\
+                      .format(" ".join([ plc.registry_xml_line() for plc in other_plcs ])))
+        utils.header("(Over)wrote {}".format(reg_fname))
         return self.test_ssh.copy_abs(agg_fname,
-                                      '/%s/etc/sfa/aggregates.xml' % self.vm_root_in_host()) == 0 \
+                                      '/{}/etc/sfa/aggregates.xml'.format(self.vm_root_in_host())) == 0 \
            and self.test_ssh.copy_abs(reg_fname,
-                                      '/%s/etc/sfa/registries.xml' % self.vm_root_in_host()) == 0
+                                      '/{}/etc/sfa/registries.xml'.format(self.vm_root_in_host())) == 0
 
     def sfa_import(self):
         "use sfaadmin to import from plc"
@@ -1663,12 +1664,12 @@ class TestPlc:
         for slice_spec in self.plc_spec['sfa']['auth_sfa_specs']:
             test_slice = TestAuthSfa(self, slice_spec)
             dir_basename = os.path.basename(test_slice.sfi_path())
-            dir_name = self.confsubdir("dot-sfi/%s" % dir_basename,
+            dir_name = self.confsubdir("dot-sfi/{}".format(dir_basename),
                                        clean=True, dry_run=self.options.dry_run)
             test_slice.sfi_configure(dir_name)
             # push into the remote /root/sfi area
             location = test_slice.sfi_path()
-            remote = "%s/%s" % (self.vm_root_in_host(), location)
+            remote = "{}/{}".format(self.vm_root_in_host(), location)
             self.test_ssh.mkdir(remote, abs=True)
             # need to strip last level or remote otherwise we get an extra dir level
             self.test_ssh.copy_abs(dir_name, os.path.dirname(remote), recursive=True)
@@ -1687,7 +1688,7 @@ class TestPlc:
         for slice_spec in self.plc_spec['sfa']['auth_sfa_specs']:
             test_slice = TestAuthSfa(self, slice_spec)
             in_vm = test_slice.sfi_path()
-            remote = "%s/%s" % (self.vm_root_in_host(), in_vm)
+            remote = "{}/{}".format(self.vm_root_in_host(), in_vm)
             if self.test_ssh.copy_abs(filename, remote) !=0:
                 overall = False
         return overall
@@ -1751,7 +1752,7 @@ class TestPlc:
         "creates random entries in the PLCAPI"
         # install the stress-test in the plc image
         location = "/usr/share/plc_api/plcsh_stress_test.py"
-        remote = "%s/%s" % (self.vm_root_in_host(), location)
+        remote = "{}/{}".format(self.vm_root_in_host(), location)
         self.test_ssh.copy_abs("plcsh_stress_test.py", remote)
         command = location
         command += " -- --preserve --short-names"
@@ -1809,29 +1810,29 @@ class TestPlc:
     def gather_slivers_var_logs(self):
         for test_sliver in self.all_sliver_objs():
             remote = test_sliver.tar_var_logs()
-            utils.system("mkdir -p logs/sliver.var-log.%s" % test_sliver.name())
-            command = remote + " | tar -C logs/sliver.var-log.%s -xf -" % test_sliver.name()
+            utils.system("mkdir -p logs/sliver.var-log.{}".format(test_sliver.name()))
+            command = remote + " | tar -C logs/sliver.var-log.{} -xf -".format(test_sliver.name())
             utils.system(command)
         return True
 
     def gather_var_logs(self):
-        utils.system("mkdir -p logs/myplc.var-log.%s" % self.name())
+        utils.system("mkdir -p logs/myplc.var-log.{}".format(self.name()))
         to_plc = self.actual_command_in_guest("tar -C /var/log/ -cf - .")        
-        command = to_plc + "| tar -C logs/myplc.var-log.%s -xf -" % self.name()
+        command = to_plc + "| tar -C logs/myplc.var-log.{} -xf -".format(self.name())
         utils.system(command)
-        command = "chmod a+r,a+x logs/myplc.var-log.%s/httpd" % self.name()
+        command = "chmod a+r,a+x logs/myplc.var-log.{}/httpd".format(self.name())
         utils.system(command)
 
     def gather_pgsql_logs(self):
-        utils.system("mkdir -p logs/myplc.pgsql-log.%s" % self.name())
+        utils.system("mkdir -p logs/myplc.pgsql-log.{}".format(self.name()))
         to_plc = self.actual_command_in_guest("tar -C /var/lib/pgsql/data/pg_log/ -cf - .")        
-        command = to_plc + "| tar -C logs/myplc.pgsql-log.%s -xf -" % self.name()
+        command = to_plc + "| tar -C logs/myplc.pgsql-log.{} -xf -".format(self.name())
         utils.system(command)
 
     def gather_root_sfi(self):
-        utils.system("mkdir -p logs/sfi.%s"%self.name())
+        utils.system("mkdir -p logs/sfi.{}".format(self.name()))
         to_plc = self.actual_command_in_guest("tar -C /root/sfi/ -cf - .")        
-        command = to_plc + "| tar -C logs/sfi.%s -xf -"%self.name()
+        command = to_plc + "| tar -C logs/sfi.{} -xf -".format(self.name())
         utils.system(command)
 
     def gather_nodes_var_logs(self):
@@ -1841,8 +1842,8 @@ class TestPlc:
                 test_node = TestNode(self, test_site, node_spec)
                 test_ssh = TestSsh(test_node.name(), key="keys/key_admin.rsa")
                 command = test_ssh.actual_command("tar -C /var/log -cf - .")
-                command = command + "| tar -C logs/node.var-log.%s -xf -" % test_node.name()
-                utils.system("mkdir -p logs/node.var-log.%s" % test_node.name())
+                command = command + "| tar -C logs/node.var-log.{} -xf -".format(test_node.name())
+                utils.system("mkdir -p logs/node.var-log.{}".format(test_node.name()))
                 utils.system(command)
 
 
@@ -1857,13 +1858,13 @@ class TestPlc:
             t = datetime.now()
             d = t.date()
             name = str(d)
-        return "/root/%s-%s.sql" % (database, name)
+        return "/root/{}-{}.sql".format(database, name)
 
     def plc_db_dump(self):
         'dump the planetlab5 DB in /root in the PLC - filename has time'
         dump=self.dbfile("planetab5")
         self.run_in_guest('pg_dump -U pgsqluser planetlab5 -f '+ dump)
-        utils.header('Dumped planetlab5 database in %s' % dump)
+        utils.header('Dumped planetlab5 database in {}'.format(dump))
         return True
 
     def plc_db_restore(self):
diff --git a/system/TestSite.py b/system/TestSite.py
index 324861e..f4d6cf2 100644
--- a/system/TestSite.py
+++ b/system/TestSite.py
@@ -13,9 +13,9 @@ from TestKey import TestKey
 
 class TestSite:
 
-    def __init__ (self,test_plc,site_spec):
-	self.test_plc=test_plc
-	self.site_spec=site_spec
+    def __init__ (self, test_plc, site_spec):
+	self.test_plc = test_plc
+	self.site_spec = site_spec
         
     def name(self):
         return self.site_spec['site_fields']['login_base']
@@ -24,38 +24,39 @@ class TestSite:
         print self.test_plc.auth_root()
         self.test_plc.apiserver.AddSite(self.test_plc.auth_root(),
                                         self.site_spec['site_fields'])
-        self.test_plc.apiserver.AddSiteAddress(self.test_plc.auth_root(),self.name(),
+        self.test_plc.apiserver.AddSiteAddress(self.test_plc.auth_root(),
+                                               self.name(),
                                                self.site_spec['address_fields'])
             
     def create_users (self):
         for user_spec in self.site_spec['users']:
-            test_user=TestUser(self.test_plc,self,user_spec)
+            test_user = TestUser(self.test_plc, self, user_spec)
             test_user.create_user()
             test_user.add_keys()            
 
     def delete_site (self):
         print self.test_plc.auth_root()
-        self.test_plc.apiserver.DeleteSite(self.test_plc.auth_root(),self.name())
+        self.test_plc.apiserver.DeleteSite(self.test_plc.auth_root(), self.name())
         return True
             
     def delete_users(self):
         for user_spec in self.site_spec['users']:
-            test_user=TestUser(self.test_plc,self,user_spec)
+            test_user = TestUser(self.test_plc, self, user_spec)
             test_user.delete_user()
 
-    def locate_user (self,username):
+    def locate_user (self, username):
         for user in self.site_spec['users']:
             if user['name'] == username:
                 return user
             if user['user_fields']['email'] == username:
                 return user
-        raise Exception,"Cannot locate user %s"%username
+        raise Exception,"Cannot locate user {}".format(username)
         
-    def locate_node (self,nodename):
+    def locate_node (self, nodename):
         for node in self.site_spec['nodes']:
             if node['name'] == nodename:
                 return node
-        raise Exception,"Cannot locate node %s"%nodename
+        raise Exception,"Cannot locate node {}".format(nodename)
         
            
     
diff --git a/system/TestSlice.py b/system/TestSlice.py
index f7e406b..3f2c5ff 100644
--- a/system/TestSlice.py
+++ b/system/TestSlice.py
@@ -15,13 +15,14 @@ from Completer import CompleterTask
 class CompleterTaskSliceSsh (CompleterTask):
 
     def __init__ (self, test_plc, hostname, slicename, private_key,command, expected, dry_run):
-        self.test_plc=test_plc
-        self.hostname=hostname
-        self.slicename=slicename
-        self.private_key=private_key
-        self.command=command
-        self.dry_run=dry_run
-        self.expected=expected
+        self.test_plc = test_plc
+        self.hostname = hostname
+        self.slicename = slicename
+        self.private_key = private_key
+        self.command = command
+        self.dry_run = dry_run
+        self.expected = expected
+
     def run (self, silent): 
         (site_spec,node_spec) = self.test_plc.locate_hostname(self.hostname)
         test_ssh = TestSsh (self.hostname,key=self.private_key,username=self.slicename)
@@ -30,31 +31,33 @@ class CompleterTaskSliceSsh (CompleterTask):
         if self.dry_run: return True
         if self.expected:       return retcod==0
         else:                   return retcod!=0
+
     def failure_epilogue (self):
         if self.expected:
-            print "Could not ssh into sliver %s@%s"%(self.slicename,self.hostname)
+            print "Could not ssh into sliver {}@{}".format(self.slicename, self.hostname)
         else:
-            print "Could still ssh into sliver%s@%s (that was expected to be down)"%(self.slicename,self.hostname)
+            print "Could still ssh into sliver{}@{} (that was expected to be down)"\
+                .format(self.slicename, self.hostname)
 
 class TestSlice:
 
-    def __init__ (self,test_plc,test_site,slice_spec):
-	self.test_plc=test_plc
-        self.test_site=test_site
-	self.slice_spec=slice_spec
-        self.test_ssh=TestSsh(self.test_plc.test_ssh)
+    def __init__ (self, test_plc, test_site, slice_spec):
+	self.test_plc = test_plc
+        self.test_site = test_site
+	self.slice_spec = slice_spec
+        self.test_ssh = TestSsh(self.test_plc.test_ssh)
         
     def name(self):
         return self.slice_spec['slice_fields']['name']
     
-    def get_slice(self,slice_name):
+    def get_slice(self, slice_name):
         for slice_spec in self.test_plc.plc_spec['slices']:
-            if(slice_spec['slice_fields']['name']== slice_name):
+            if slice_spec['slice_fields']['name'] == slice_name:
                 return slice_spec
 
     def owner_auth(self):
         owner_spec = self.test_site.locate_user(self.slice_spec['owner'])
-        return TestUser(self,self.test_site,owner_spec).auth()
+        return TestUser(self, self.test_site, owner_spec).auth()
 
     def slice_name (self):
         return self.slice_spec['slice_fields']['name']
@@ -64,29 +67,31 @@ class TestSlice:
         auth = self.owner_auth()
         slice_fields = self.slice_spec['slice_fields']
         slice_name = slice_fields['name']
-        utils.header("Creating slice %s"%slice_name)
-        self.test_plc.apiserver.AddSlice(auth,slice_fields)
+        utils.header("Creating slice {}".format(slice_name))
+        self.test_plc.apiserver.AddSlice(auth, slice_fields)
         for username in self.slice_spec['usernames']:
-                user_spec=self.test_site.locate_user(username)
-                test_user=TestUser(self,self.test_site,user_spec)
+                user_spec = self.test_site.locate_user(username)
+                test_user = TestUser(self,self.test_site,user_spec)
                 self.test_plc.apiserver.AddPersonToSlice(auth, test_user.name(), slice_name)
         # add initscript code or name as appropriate
         if self.slice_spec.has_key('initscriptcode'):
-            iscode=self.slice_spec['initscriptcode']
-            utils.header("Adding initscript code %s in %s"%(iscode,slice_name))
-            self.test_plc.apiserver.AddSliceTag(self.test_plc.auth_root(), slice_name,'initscript_code',iscode)
+            iscode = self.slice_spec['initscriptcode']
+            utils.header("Adding initscript code {} in {}".format(iscode, slice_name))
+            self.test_plc.apiserver.AddSliceTag(self.test_plc.auth_root(), slice_name,
+                                                'initscript_code', iscode)
         elif self.slice_spec.has_key('initscriptname'):
-            isname=self.slice_spec['initscriptname']
-            utils.header("Adding initscript name %s in %s"%(isname,slice_name))
-            self.test_plc.apiserver.AddSliceTag(self.test_plc.auth_root(), slice_name,'initscript',isname)
+            isname = self.slice_spec['initscriptname']
+            utils.header("Adding initscript name {} in {}".format(isname, slice_name))
+            self.test_plc.apiserver.AddSliceTag(self.test_plc.auth_root(), slice_name,
+                                                'initscript', isname)
         if 'omf-friendly' in self.slice_spec:
-            utils.header("Making slice %s OMF-friendly"%slice_name)
-            self.test_plc.apiserver.AddSliceTag(self.test_plc.auth_root(), slice_name,'vref','omf')
-            self.test_plc.apiserver.AddSliceTag(self.test_plc.auth_root(), slice_name,'omf_control','yes')
+            utils.header("Making slice {} OMF-friendly".format(slice_name))
+            self.test_plc.apiserver.AddSliceTag(self.test_plc.auth_root(), slice_name, 'vref', 'omf')
+            self.test_plc.apiserver.AddSliceTag(self.test_plc.auth_root(), slice_name, 'omf_control', 'yes')
 # setting vref directly like this was useful for multi-arch tests long ago - see wifilab
 # however this should rather use other tags by now, so we drop this for now
 #        if self.slice_spec.has_key ('vref'):
-#            vref_value=self.slice_spec['vref']
+#            vref_value = self.slice_spec['vref']
 #            self.test_plc.apiserver.AddSliceTag(self.test_plc.auth_root(), slice_name,'vref',vref_value)
         # epilogue
         self.add_nodes()
@@ -96,14 +101,14 @@ class TestSlice:
         auth = self.owner_auth()
         slice_fields = self.slice_spec['slice_fields']
         slice_name = slice_fields['name']
-        vsys_tags = self.test_plc.apiserver.GetSliceTags (auth,{'tagname':'vsys','name':slice_name})
-        values=[ st['value'] for st in vsys_tags ]
-        expected=self.test_plc.plc_spec['expected_vsys_tags']
+        vsys_tags = self.test_plc.apiserver.GetSliceTags (auth, {'tagname' : 'vsys', 'name' : slice_name})
+        values = [st['value'] for st in vsys_tags]
+        expected = self.test_plc.plc_spec['expected_vsys_tags']
         result = set(values) == set(expected)
         if not result:
-            print 'Check vsys defaults with slice %s'%slice_name
-            print 'Expected %s'%expected
-            print 'Got %s'%values
+            print 'Check vsys defaults with slice {}'.format(slice_name)
+            print 'Expected {}'.format(expected)
+            print 'Got {}'.format(values)
         return result
 
     # just add the nodes and handle tags
@@ -115,25 +120,25 @@ class TestSlice:
             node_spec=self.test_site.locate_node(nodename)
             test_node=TestNode(self.test_plc,self.test_site,node_spec)
             hostnames += [test_node.name()]
-        utils.header("Adding %r in %s"%(hostnames,slice_name))
+        utils.header("Adding {} in {}".format(hostnames, slice_name))
         self.test_plc.apiserver.AddSliceToNodes(auth, slice_name, hostnames)
         
     # trash the slice altogether
     def delete_slice(self):
         auth = self.owner_auth()
         slice_name = self.slice_name()
-        utils.header("Deleting slice %s"%slice_name)
+        utils.header("Deleting slice {}".format(slice_name))
         self.test_plc.apiserver.DeleteSlice(auth,slice_name)
 
     # keep the slice alive and just delete nodes
     def delete_nodes (self):
         auth = self.owner_auth()
         slice_name = self.slice_name()
-        print 'retrieving slice %s'%slice_name
+        print 'retrieving slice {}'.format(slice_name)
         slice=self.test_plc.apiserver.GetSlices(auth,slice_name)[0]
         node_ids=slice['node_ids']
-        utils.header ("Deleting %d nodes from slice %s"%\
-                          (len(node_ids),slice_name))
+        utils.header ("Deleting {} nodes from slice {}"\
+                      .format(len(node_ids), slice_name))
         self.test_plc.apiserver.DeleteSliceFromNodes (auth,slice_name, node_ids)
 
     def locate_private_key(self):
@@ -162,17 +167,17 @@ class TestSlice:
 #        graceout = timedelta(minutes=silent_minutes)
 #        period   = timedelta(seconds=period_seconds)
         if not command:
-            command="echo hostname ; hostname; echo id; id; echo uname -a ; uname -a"
+            command = "echo hostname ; hostname; echo id; id; echo uname -a ; uname -a"
         # locate a key
-        private_key=self.locate_private_key()
+        private_key = self.locate_private_key()
         if not private_key :
-            utils.header("WARNING: Cannot find a valid key for slice %s"%self.name())
+            utils.header("WARNING: Cannot find a valid key for slice {}".format(self.name()))
             return False
 
         # convert nodenames to real hostnames
         if expected:    msg="ssh slice access enabled"
         else:           msg="ssh slice access disabled"
-        utils.header("checking for %s -- slice %s"%(msg,self.name()))
+        utils.header("checking for {} -- slice {}".format(msg, self.name()))
 
         tasks=[]
         slicename=self.name()
@@ -198,7 +203,7 @@ class TestSlice:
         # locate a key
         private_key=self.locate_private_key()
         if not private_key :
-            utils.header("WARNING: Cannot find a valid key for slice %s"%self.name())
+            utils.header("WARNING: Cannot find a valid key for slice {}".format(self.name()))
             return False
 
         # convert nodenames to real hostnames
@@ -207,18 +212,24 @@ class TestSlice:
         (site_spec,node_spec) = self.test_plc.locate_node(nodename)
         hostname=node_spec['node_fields']['hostname']
 
-        if expected:    msg="%s to return TRUE from ssh"%command
-        else:           msg="%s to return FALSE from ssh"%command
+        if expected:
+            msg="{} to return TRUE from ssh".format(command)
+        else:
+            msg="{} to return FALSE from ssh".format(command)
             
-        utils.header("checking %s -- slice %s on node %s"%(msg,self.name(),hostname))
+        utils.header("checking {} -- slice {} on node {}".format(msg, self.name(), hostname))
         (site_spec,node_spec) = self.test_plc.locate_hostname(hostname)
         test_ssh = TestSsh (hostname,key=private_key,username=self.name())
         full_command = test_ssh.actual_command(command)
         retcod = utils.system (full_command,silent=True)
-        if getattr(options,'dry_run',None): return True
-        if expected:    success = retcod==0
-        else:           success = retcod!=0
-        if not success: utils.header ("WRONG RESULT for %s"%msg)
+        if getattr(options,'dry_run',None):
+            return True
+        if expected:
+            success = retcod==0
+        else:
+            success = retcod!=0
+        if not success:
+            utils.header ("WRONG RESULT for {}".format(msg))
         return success
 
     # for TestPlc.slice_mapper__tasks
@@ -234,15 +245,16 @@ class TestSlice:
         # use constant admin key
         local_key = "keys/key_admin.rsa"
         node_infos = self.test_plc.all_node_infos()
-        rootfs="/vservers/%s"%self.name()
+        rootfs="/vservers/{}".format(self.name())
         class CompleterTaskRootfs (CompleterTaskNodeSsh):
             def __init__ (self, nodename, qemuname):
                 CompleterTaskNodeSsh.__init__(self,nodename, qemuname, local_key, expected=expected,
-                                              command="ls -d %s"%rootfs)
+                                              command="ls -d {}".format(rootfs))
             def failure_epilogue (self):
                 if expected:
-                    print "Could not stat %s - was expected to be present"%rootfs
+                    print "Could not stat {} - was expected to be present".format(rootfs)
                 else:
-                    print "Sliver rootfs %s still present - this is unexpected"%rootfs
-                    utils.system(self.test_ssh.actual_command("ls -l %s; du -hs %s"%(rootfs,rootfs),dry_run=self.dry_run))
+                    print "Sliver rootfs {} still present - this is unexpected".format(rootfs)
+                    utils.system(self.test_ssh.actual_command("ls -l {rootfs}; du -hs {rootfs}".format(**locals()),
+                                                              dry_run=self.dry_run))
         return [ CompleterTaskRootfs (nodename, qemuname) for (nodename,qemuname) in node_infos ]
diff --git a/system/TestSliceSfa.py b/system/TestSliceSfa.py
index 341f518..f55679a 100644
--- a/system/TestSliceSfa.py
+++ b/system/TestSliceSfa.py
@@ -19,10 +19,10 @@ from TestSlice import CompleterTaskSliceSsh
 class TestSliceSfa:
 
     def __init__ (self, test_auth_sfa, slice_spec):
-        self.test_auth_sfa=test_auth_sfa
-        self.slice_spec=slice_spec
+        self.test_auth_sfa = test_auth_sfa
+        self.slice_spec = slice_spec
         # shortcuts
-        self.test_plc=self.test_auth_sfa.test_plc
+        self.test_plc = self.test_auth_sfa.test_plc
 
     def hrn (self): 
         return self.test_auth_sfa.obj_hrn(self.slice_spec['name'])
@@ -36,19 +36,21 @@ class TestSliceSfa:
     def sfi_user(self,*args,**kwds): return self.test_auth_sfa.sfi_user(*args, **kwds)
 
     def discover_option(self):
-        if self.rspec_style()=='pg': return "-r GENI"
-        else:                        return "-r sfa"
+        if self.rspec_style() == 'pg':
+            return "-r GENI"
+        else:
+            return "-r sfa"
 
     # those are step names exposed as methods of TestPlc, hence the _sfa
 
     # needs to be run as pi
     def sfa_register_slice(self,options):
         "run sfi register (on Registry)"
-        sfi_command="register"
+        sfi_command  = "register"
         sfi_command += " --type slice"
-        sfi_command += " --xrn %s"%self.hrn()
+        sfi_command += " --xrn {}".format(self.hrn())
         for opt in self.slice_spec['register_options']:
-            sfi_command += " %s"%(opt)
+            sfi_command += " {}".format(opt)
 	return self.test_plc.run_in_guest(self.sfi_pi(sfi_command))==0
 
     def sfa_renew_slice(self, options):
@@ -60,45 +62,46 @@ class TestSliceSfa:
         # we expect this to fail on too long term attemps, but to succeed otherwise
         overall=True
         for ( renew_until, expected) in [ (too_late, False), (one_month, True) ] :
-            sfi_command="renew"
-            sfi_command += " %s"%self.hrn()
-            sfi_command += " %s"%renew_until
+            sfi_command = "renew"
+            sfi_command += " {}".format(self.hrn())
+            sfi_command += " {}".format(renew_until)
             succeeded = self.test_plc.run_in_guest(self.sfi_user(sfi_command))==0
-            if succeeded!=expected:
-                utils.header ("Expecting success=%s, got %s"%(expected,succeeded))
+            if succeeded != expected:
+                utils.header ("Expecting success={}, got {}".format(expected, succeeded))
                 # however it turns out sfi renew always returns fine....
                 #overall=False
             # so for helping manual checks:
             # xxx this should use sfa_get_expires below and actually check the expected result
-            sfi_command="show -k hrn -k expires %s"%self.hrn()
+            sfi_command = "show -k hrn -k expires {}".format(self.hrn())
             self.test_plc.run_in_guest(self.sfi_user(sfi_command))
         return overall
 
     def sfa_get_expires (self, options):
-        filename="%s.json"%self.hrn()
+        filename = "{}.json".format(self.hrn())
         # /root/sfi/pg/<>
-        inplc_filename=os.path.join(self.sfi_path(),filename)
+        inplc_filename = os.path.join(self.sfi_path(),filename)
         # /vservers/<>/root/sfi/... - cannot use os.path 
-        inbox_filename="%s%s"%(self.test_plc.vm_root_in_host(),inplc_filename)
-        sfi_command  =""
-        sfi_command += "-R %s --rawformat json"%inplc_filename
+        inbox_filename = "{}{}".format(self.test_plc.vm_root_in_host(), inplc_filename)
+        sfi_command  = ""
+        sfi_command += "-R {} --rawformat json".format(inplc_filename)
         sfi_command += " status"
-        sfi_command += " %s"%self.hrn()
+        sfi_command += " {}".format(self.hrn())
         # cannot find it if sfi status returns an error
         if self.test_plc.run_in_guest (self.sfi_user(sfi_command)) !=0: return
         if self.test_plc.test_ssh.fetch(inbox_filename,filename)!=0: return 
         try:
-            with file(filename) as f: status = json.loads(f.read())
-            value=status['value']
-            sliver=value['geni_slivers'][0]
-            expires=sliver['geni_expires']
-            print " * expiration for %s (first sliver) -> %s"%(self.hrn(),expires)
+            with file(filename) as f:
+                status = json.loads(f.read())
+            value = status['value']
+            sliver = value['geni_slivers'][0]
+            expires = sliver['geni_expires']
+            print " * expiration for {} (first sliver) -> {}".format(self.hrn(), expires)
             return expires
         except:
             traceback.print_exc()
 
     # helper - filename to store a given result
-    def _resname (self,name,ext): return "%s.%s"%(name,ext)
+    def _resname (self,name,ext): return "{}.{}".format(name, ext)
     def adfile (self): return self._resname("ad","rspec")
     def reqfile (self): return self._resname("req","rspec")
     def empty_reqfile (self): return "empty-rspec.xml"
@@ -108,22 +111,25 @@ class TestSliceSfa:
     def sfa_discover(self,options):
         "discover resources into resouces_in.rspec"
         return self.test_plc.run_in_guest(self.sfi_user(\
-                "resources %s -o %s/%s"% (self.discover_option(),self.sfi_path(),self.adfile())))==0
+                "resources {} -o {}/{}"\
+                    .format(self.discover_option(),self.sfi_path(),self.adfile()))) == 0
 
     def sfa_rspec(self,options):
         "invoke sfiListNodes and sfiAddSlivers to prepare a rspec"
-        commands=[
-            "sfiListNodes.py -i %s/%s -o %s/%s"%(self.sfi_path(),self.adfile(),self.sfi_path(),self.nodefile()),
-            "sfiAddSliver.py -i %s/%s -n %s/%s -o %s/%s"%\
-                (self.sfi_path(),self.adfile(),self.sfi_path(),self.nodefile(),self.sfi_path(),self.reqfile()),
+        commands = [
+            "sfiListNodes.py -i {}/{} -o {}/{}".format(self.sfi_path(), self.adfile(),
+                                                       self.sfi_path(), self.nodefile()),
+            "sfiAddSliver.py -i {}/{} -n {}/{} -o {}/{}".format(self.sfi_path(), self.adfile(),
+                                                                self.sfi_path(), self.nodefile(),
+                                                                self.sfi_path(), self.reqfile()),
             ]
         for command in commands:
-            if self.test_plc.run_in_guest(command)!=0: return False
+            if self.test_plc.run_in_guest(command) != 0: return False
         return True
 
     def _sfa_allocate(self,file,options):
-        command=self.sfi_user("allocate %s %s"%(self.hrn(),file))
-        return self.test_plc.run_in_guest(command)==0
+        command = self.sfi_user("allocate {} {}".format(self.hrn(), file))
+        return self.test_plc.run_in_guest(command) == 0
 
     def sfa_allocate(self,options):
         "invoke run sfi allocate (on SM)"
@@ -134,32 +140,33 @@ class TestSliceSfa:
 
     def sfa_provision(self,options):
         "invoke run sfi provision (on SM)"
-        command=self.sfi_user("provision %s"%(self.hrn()))
-        return self.test_plc.run_in_guest(command)==0
+        command = self.sfi_user("provision {}".format(self.hrn()))
+        return self.test_plc.run_in_guest(command) == 0
     # just a synonym
     sfa_provision_empty = sfa_provision
 
     def plc_name (self):
-        return "%s_%s"%(self.test_auth_sfa.login_base,self.slice_spec['name'])
+        return "{}_{}".format(self.test_auth_sfa.login_base, self.slice_spec['name'])
 
     # all local nodes in slice ?
     def sfa_check_slice_plc (self,options):
         "check the slice has been created at the plc - all local nodes should be in slice"
-        slice=self.test_plc.apiserver.GetSlices(self.test_plc.auth_root(), self.plc_name())[0]
-        nodes=self.test_plc.apiserver.GetNodes(self.test_plc.auth_root(), {'peer_id':None})
-        result=True
+        slice = self.test_plc.apiserver.GetSlices(self.test_plc.auth_root(), self.plc_name())[0]
+        nodes = self.test_plc.apiserver.GetNodes(self.test_plc.auth_root(), {'peer_id':None})
+        result = True
         for node in nodes: 
             if node['node_id'] in slice['node_ids']:
-                utils.header("local node %s found in slice %s"%(node['hostname'],slice['name']))
+                utils.header("local node {} found in slice {}".format(node['hostname'], slice['name']))
             else:
-                utils.header("ERROR - local node %s NOT FOUND in slice %s"%(node['hostname'],slice['name']))
-                result=False
+                utils.header("ERROR - local node {} NOT FOUND in slice {}"\
+                             .format(node['hostname'], slice['name']))
+                result = False
         return result
 
     # no node left in slice ?
     def sfa_check_slice_plc_empty (self,options):
         "check the slice have been emptied at the plcs - no node should be in slice"
-        slices=self.test_plc.apiserver.GetSlices(self.test_plc.auth_root(), 
+        slices = self.test_plc.apiserver.GetSlices(self.test_plc.auth_root(), 
                                                  self.plc_name(),
                                                  ['node_ids'])
         return not slices[0]['node_ids']
@@ -174,14 +181,14 @@ class TestSliceSfa:
     # run as pi
     def sfa_delete_slice(self,options):
 	"run sfi delete"
-	self.test_plc.run_in_guest(self.sfi_pi("delete %s"%(self.hrn(),)))
-	return self.test_plc.run_in_guest(self.sfi_pi("remove -t slice %s"%(self.hrn(),)))==0
+	self.test_plc.run_in_guest(self.sfi_pi("delete {}".format(self.hrn())))
+	return self.test_plc.run_in_guest(self.sfi_pi("remove -t slice {}".format(self.hrn()))) == 0
 
     def locate_private_key(self):
         return self.test_plc.locate_private_key_from_key_names ( [ self.slice_spec['key_name'] ] )
 
     # check the resulting sliver
-    def ssh_slice_sfa(self,options,timeout_minutes=40,silent_minutes=0,period_seconds=15):
+    def ssh_slice_sfa(self, options, timeout_minutes=40, silent_minutes=0, period_seconds=15):
 	"tries to ssh-enter the SFA slice"
         timeout  = timedelta(minutes=timeout_minutes)
         graceout = timedelta(minutes=silent_minutes)
@@ -189,7 +196,7 @@ class TestSliceSfa:
         # locate a key
         private_key=self.locate_private_key()
         if not private_key :
-            utils.header("WARNING: Cannot find a valid key for slice %s"%self.name())
+            utils.header("WARNING: Cannot find a valid key for slice {}".format(self.name()))
             return False
         command="echo hostname ; hostname; echo id; id; echo uname -a ; uname -a"
         
@@ -198,6 +205,7 @@ class TestSliceSfa:
         dry_run = getattr(options,'dry_run',False)
         for nodename in self.slice_spec['nodenames']:
             (site_spec,node_spec) = self.test_plc.locate_node(nodename)
-            tasks.append( CompleterTaskSliceSsh(self.test_plc,node_spec['node_fields']['hostname'],
-                                                slicename,private_key,command,expected=True,dry_run=dry_run))
-        return Completer (tasks, message='ssh_slice_sfa').run (timeout, graceout, period)
+            tasks.append( CompleterTaskSliceSsh(self.test_plc, node_spec['node_fields']['hostname'],
+                                                slicename, private_key, command,
+                                                expected=True, dry_run=dry_run))
+        return Completer (tasks, message='ssh_slice_sfa').run(timeout, graceout, period)
diff --git a/system/TestSliver.py b/system/TestSliver.py
index e4f49f7..264e0a3 100644
--- a/system/TestSliver.py
+++ b/system/TestSliver.py
@@ -9,47 +9,47 @@ from TestSsh import TestSsh
 
 class TestSliver:
 
-    def __init__ (self,test_plc,test_node,test_slice):
-        self.test_plc=test_plc
-	self.test_node=test_node
-        self.test_slice=test_slice
+    def __init__(self, test_plc, test_node, test_slice):
+        self.test_plc = test_plc
+	self.test_node = test_node
+        self.test_slice = test_slice
         self.test_ssh = self.create_test_ssh()
 
     def get_privateKey(self):
-        slice_spec=self.test_slice.slice_spec
+        slice_spec = self.test_slice.slice_spec
         try:
-            (found,privatekey)=self.test_slice.locate_key()
-            return (found,privatekey)
+            (found, privatekey) = self.test_slice.locate_key()
+            return (found, privatekey)
         except Exception,e:
             print str(e)
             
     def create_test_ssh(self):
         private_key = self.test_slice.locate_private_key()
         if not private_key:
-            raise Exception,"Cannot find the private key for slice %s"%self.test_slice.name()
-        return TestSsh (self.test_node.name(),key=private_key,username=self.test_slice.name(),
+            raise Exception,"Cannot find the private key for slice {}".format(self.test_slice.name())
+        return TestSsh (self.test_node.name(), key=private_key, username=self.test_slice.name(),
                         # so that copies end up in the home dir
                         buildname=".")
 
     def name(self):
-        return "%s@%s"%(self.test_slice.name(),self.test_node.name())
+        return "{}@{}".format(self.test_slice.name(), self.test_node.name())
 
     def check_initscript_stamp(self, stamp):
-        utils.header("Checking for initscript stamp %s on sliver %s"%(stamp, self.name()))
-        return self.test_ssh.run("ls -l /var/tmp/%s.stamp"%stamp)==0
+        utils.header("Checking for initscript stamp {} on sliver {}".format(stamp, self.name()))
+        return self.test_ssh.run("ls -l /var/tmp/{}.stamp".format(stamp)) == 0
     
     def check_tcp_ready (self, port):
-        ready_command = "./tcptest.py ready -p %d"%(port)
+        ready_command = "./tcptest.py ready -p {}".format(port)
         return self.test_ssh.copy("tcptest.py") == 0 and \
             self.test_ssh.run(ready_command) == 0
 
     def run_tcp_server (self, port, timeout=10):
-        server_command = "./tcptest.py server -p %d -t %d"%(port, timeout)
+        server_command = "./tcptest.py server -p {} -t {}".format(port, timeout)
         return self.test_ssh.copy("tcptest.py") == 0 and \
-            self.test_ssh.run(server_command, background=True)==0
+            self.test_ssh.run(server_command, background=True) == 0
 
     def run_tcp_client (self, servername, port, retry=5):
-        client_command="./tcptest.py client -a %s -p %d"%(servername, port)
+        client_command = "./tcptest.py client -a {} -p {}".format(servername, port)
         if self.test_ssh.copy("tcptest.py") != 0:
             return False
         if self.test_ssh.run(client_command) == 0:
@@ -60,15 +60,15 @@ class TestSliver:
     #def tar_var_logs (self):
     #    return self.test_ssh.actual_command("sudo tar -C /var/log -cf - .")
     def tar_var_logs (self):
-        test_ssh=self.test_node.create_test_ssh()
-        dir_to_tar="/vservers/%s/var/log"%self.test_slice.name()
-        return test_ssh.actual_command("tar -C %s -cf - ."%dir_to_tar)
+        test_ssh = self.test_node.create_test_ssh()
+        dir_to_tar = "/vservers/{}/var/log".format(self.test_slice.name())
+        return test_ssh.actual_command("tar -C {} -cf - .".format(dir_to_tar))
     
     def check_hooks (self):
         print 'NOTE: slice hooks check scripts NOT (yet?) run in sudo'
         extensions = [ 'py','pl','sh' ]
-        path='hooks/slice/'
-        scripts=utils.locate_hooks_scripts ('sliver '+self.name(), path,extensions)
+        path = 'hooks/slice/'
+        scripts = utils.locate_hooks_scripts ('sliver '+self.name(), path,extensions)
         overall = True
         for script in scripts:
             if not self.check_hooks_script (script):
@@ -76,15 +76,15 @@ class TestSliver:
         return overall
 
     def check_hooks_script (self,local_script):
-        script_name=os.path.basename(local_script)
-        utils.header ("SLIVER hook %s (%s)"%(script_name,self.name()))
-        test_ssh=self.create_test_ssh()
+        script_name = os.path.basename(local_script)
+        utils.header ("SLIVER hook {} ({})".format(script_name, self.name()))
+        test_ssh = self.create_test_ssh()
         test_ssh.copy_home(local_script)
         if test_ssh.run("./"+script_name) != 0:
-            utils.header ("WARNING: hooks check script %s FAILED (ignored)"%script_name)
+            utils.header ("WARNING: hooks check script {} FAILED (ignored)".format(script_name))
             #return False
             return True
         else:
-            utils.header ("SUCCESS: sliver hook %s OK"%script_name)
+            utils.header ("SUCCESS: sliver hook {} OK".format(script_name))
             return True
     
diff --git a/system/TestSsh.py b/system/TestSsh.py
index 1c5d601..c025e03 100644
--- a/system/TestSsh.py
+++ b/system/TestSsh.py
@@ -45,7 +45,7 @@ class TestSsh:
             remote_ip = socket.gethostbyname(hostname)
             return local_ip == remote_ip
         except:
-            utils.header("WARNING : something wrong in is_local_hostname with hostname=%s"%hostname)
+            utils.header("WARNING : something wrong in is_local_hostname with hostname={}".format(hostname))
             return False
 
     # some boxes have their working space in user's homedir (/root), 
@@ -74,13 +74,13 @@ class TestSsh:
     def key_part(self):
         if not self.key:
             return ""
-        return "-i %s " % self.key
+        return "-i {} ".format(self.key)
 
     def hostname_part(self):
         if not self.username:
             return self.hostname
         else:
-            return "%s@%s" % (self.username,self.hostname)
+            return "{}@{}".format(self.username,self.hostname)
     
     # command gets run on the right box
     def actual_command(self, command, keep_stdin=False, dry_run=False, backslash=True):
@@ -136,7 +136,7 @@ class TestSsh:
         if self.is_local():
             return utils.system(command, background)
         self.create_buildname_once(dry_run)
-        return self.run("cd %s ; %s" % (self.fullname(self.buildname), command),
+        return self.run("cd {} ; {}".format(self.fullname(self.buildname), command),
                         background=background, dry_run=dry_run)
 
     def fullname(self, dirname):
@@ -153,13 +153,13 @@ class TestSsh:
         # ab. paths remain as-is
         if not abs:
             if dirname:
-                dirname = "%s/%s" % (self.buildname,dirname)
+                dirname = "{}/{}".format(self.buildname, dirname)
             else:
                 dirname = self.buildname
             dirname = self.fullname(dirname)
         if dirname == '.':
             return
-        return self.run("mkdir -p %s" % dirname, dry_run=dry_run)
+        return self.run("mkdir -p {}".format(dirname), dry_run=dry_run)
 
     def rmdir(self, dirname=None, dry_run=False):
         if self.is_local():
@@ -167,11 +167,11 @@ class TestSsh:
                 return shutil.rmtree(dirname)
             return 0
         if dirname:
-            dirname = "%s/%s" % (self.buildname,dirname)
+            dirname = "{}/{}".format(self.buildname, dirname)
         else:
             dirname = self.buildname
         dirname = self.fullname(dirname)
-        return self.run("rm -rf %s" % dirname, dry_run=dry_run)
+        return self.run("rm -rf {}".format(dirname), dry_run=dry_run)
 
     def create_buildname_once(self, dry_run):
         if self.is_local():
@@ -193,11 +193,11 @@ class TestSsh:
         if recursive:
             scp_command += "-r "
         scp_command += self.key_part()
-        scp_command += "%s %s:%s/%s" % (local_file, self.hostname_part(),
-                                        self.fullname(self.buildname),
-                                        os.path.basename(local_file) or ".")
+        scp_command += "{} {}:{}/{}".format(local_file, self.hostname_part(),
+                                            self.fullname(self.buildname),
+                                            os.path.basename(local_file) or ".")
         if dry_run:
-            utils.header("DRY RUN TestSsh.copy %s" % scp_command)
+            utils.header("DRY RUN TestSsh.copy {}".format(scp_command))
             # need to be consistent with the non-dry-run mode
             return 0
         return utils.system(scp_command)
@@ -207,15 +207,15 @@ class TestSsh:
         if self.is_local():
             dest = ""
         else:
-            dest = "%s:" % self.hostname_part()
+            dest = "{}:".format(self.hostname_part())
         scp_command = "scp "
         scp_command += TestSsh.std_options
         if recursive:
             scp_command += "-r "
         scp_command += self.key_part()
-        scp_command += "%s %s%s" % (local_file, dest, remote_file)
+        scp_command += "{} {}{}".format(local_file, dest, remote_file)
         if dry_run:
-            utils.header("DRY RUN TestSsh.copy %s" % scp_command)
+            utils.header("DRY RUN TestSsh.copy {}".format(scp_command))
             # need to be consistent with the non-dry-run mode
             return 0
         return utils.system(scp_command)
@@ -228,7 +228,7 @@ class TestSsh:
             command="cp "
             if recursive:
                 command += "-r "
-            command += "%s %s" % (remote_file,local_file)
+            command += "{} {}".format(remote_file, local_file)
         else:
             command = "scp "
             if not dry_run:
@@ -240,9 +240,9 @@ class TestSsh:
             if remote_file.find("/") == 0:
                 remote_path = remote_file
             else:
-                remote_path = "%s/%s" % (self.buildname, remote_file)
+                remote_path = "{}/{}".format(self.buildname, remote_file)
                 remote_path = self.fullname(remote_path)
-            command += "%s:%s %s" % (self.hostname_part(), remote_path, local_file)
+            command += "{}:{} {}".format(self.hostname_part(), remote_path, local_file)
         return utils.system(command)
 
     # this is only to avoid harmless message when host cannot be identified
@@ -250,7 +250,7 @@ class TestSsh:
     # the only place where this is needed is when tring to reach a slice in a node,
     # which is done from the test master box
     def clear_known_hosts(self):
-        known_hosts = "%s/.ssh/known_hosts" % os.getenv("HOME")
-        utils.header("Clearing entry for %s in %s" % (self.hostname, known_hosts))
-        return utils.system("sed -i -e /^%s/d %s" % (self.hostname, known_hosts))
+        known_hosts = "{}/.ssh/known_hosts".format(os.getenv("HOME"))
+        utils.header("Clearing entry for {} in {}".format(self.hostname, known_hosts))
+        return utils.system("sed -i -e /^{}/d {}".format(self.hostname, known_hosts))
         
diff --git a/system/TestUser.py b/system/TestUser.py
index 12728ee..77d4448 100644
--- a/system/TestUser.py
+++ b/system/TestUser.py
@@ -8,42 +8,42 @@ import utils
 
 class TestUser:
 
-    def __init__ (self,test_plc,test_site,user_spec):
-	self.test_plc=test_plc
-	self.test_site=test_site
-	self.user_spec=user_spec
+    def __init__ (self, test_plc, test_site, user_spec):
+	self.test_plc = test_plc
+	self.test_site = test_site
+	self.user_spec = user_spec
 
     def name(self):
         return self.user_spec['user_fields']['email']
 
     def auth (self):
-        person=self.user_spec['user_fields']
-        return {'Username':person['email'],
-                'AuthMethod':'password',
-                'AuthString':person['password'],
-                'Role':self.user_spec['roles'][0],
+        person = self.user_spec['user_fields']
+        return {'Username'   : person['email'],
+                'AuthMethod' : 'password',
+                'AuthString' : person['password'],
+                'Role'       : self.user_spec['roles'][0],
                 }
 
     def create_user (self):
-        user_spec=self.user_spec
-        fields=user_spec['user_fields']
-        auth=self.test_plc.auth_root()
-        utils.header('Adding user %s - roles %r'%(fields['email'],user_spec['roles']))
-        self.test_plc.apiserver.AddPerson(auth,fields)
-        self.test_plc.apiserver.UpdatePerson(auth,fields['email'],{'enabled': True})
+        user_spec = self.user_spec
+        fields = user_spec['user_fields']
+        auth = self.test_plc.auth_root()
+        utils.header('Adding user {} - roles {}'.format(fields['email'], user_spec['roles']))
+        self.test_plc.apiserver.AddPerson(auth, fields)
+        self.test_plc.apiserver.UpdatePerson(auth, fields['email'], {'enabled': True})
         for role in user_spec['roles']:
             self.test_plc.apiserver.AddRoleToPerson(auth,role,fields['email'])
         self.test_plc.apiserver.AddPersonToSite(auth,
-                                             self.name(),
-                                             self.test_site.name())
+                                                self.name(),
+                                                self.test_site.name())
 
     def delete_user(self):
-        auth=self.test_plc.auth_root()
+        auth = self.test_plc.auth_root()
         self.test_plc.apiserver.DeletePerson(auth,self.name())
 
     def add_keys (self):
-        user_spec=self.user_spec
+        user_spec = self.user_spec
         for key_name in user_spec['key_names']:
-            key_spec=self.test_plc.locate_key(key_name)
-            auth=self.auth()
+            key_spec = self.test_plc.locate_key(key_name)
+            auth = self.auth()
             self.test_plc.apiserver.AddPersonKey(auth,self.name(), key_spec['key_fields'])
diff --git a/system/TestUserSfa.py b/system/TestUserSfa.py
index 68530e5..ab73cb9 100644
--- a/system/TestUserSfa.py
+++ b/system/TestUserSfa.py
@@ -8,48 +8,47 @@ import utils
 
 class TestUserSfa:
 
-    def __init__ (self,test_auth_sfa, user_spec):
-        self.test_auth_sfa=test_auth_sfa
-        self.user_spec=user_spec
+    def __init__ (self, test_auth_sfa, user_spec):
+        self.test_auth_sfa = test_auth_sfa
+        self.user_spec = user_spec
         # shortcuts
-        self.test_plc=self.test_auth_sfa.test_plc
-        self.login_base=self.test_auth_sfa.login_base
+        self.test_plc = self.test_auth_sfa.test_plc
+        self.login_base = self.test_auth_sfa.login_base
 
     def sfi_path(self):
         return self.test_auth_sfa.sfi_path()
     def hrn(self):
         return self.test_auth_sfa.obj_hrn(self.user_spec['name'])
-    def sfi_pi(self,*args,**kwds):
+    def sfi_pi(self, *args, **kwds):
         return self.test_auth_sfa.sfi_pi(*args, **kwds)
-    def sfi_user(self,*args,**kwds):
+    def sfi_user(self, *args, **kwds):
         return self.test_auth_sfa.sfi_user(*args, **kwds)
 
     # xxx todo - not the right place any longer - or is it ?
-    def sfa_register_user (self,options):
+    def sfa_register_user (self, options):
         "add a regular user using sfi register"
         user_hrn = self.hrn()
-        command="register"
+        command = "register"
         command += " --type user"
-        command += " --xrn %s"%user_hrn
-        command += " --email %s"%self.user_spec['email']
+        command += " --xrn {}".format(user_hrn)
+        command += " --email {}".format(self.user_spec['email'])
         command += " " + " ".join(self.user_spec['register_options'])
         # handle key separately because of embedded whitespace
         # hack - the user's pubkey is avail from his hrn
-        command += " -k %s/%s.pub"%(self.sfi_path(),user_hrn)
-	return self.test_plc.run_in_guest(self.sfi_pi(command))==0
+        command += " -k {}/{}.pub".format(self.sfi_path(), user_hrn)
+	return self.test_plc.run_in_guest(self.sfi_pi(command)) == 0
 
     def sfa_update_user (self,options):
         "update a user record using sfi update"
         user_hrn = self.hrn()
         command="update"
         command += " --type user"
-        command += " --xrn %s"%user_hrn
+        command += " --xrn {}".format(user_hrn)
         command += " " + " ".join(self.user_spec['update_options'])
-	return self.test_plc.run_in_guest(self.sfi_pi(command))==0
+	return self.test_plc.run_in_guest(self.sfi_pi(command)) == 0
 
     def sfa_delete_user(self,options):
 	"run sfi delete on user record"
         user_hrn = self.hrn()
-        command="remove -t user %s"%user_hrn
-	return \
-            self.test_plc.run_in_guest(self.sfi_pi(command))==0
+        command = "remove -t user {}".format(user_hrn)
+	return self.test_plc.run_in_guest(self.sfi_pi(command)) == 0
diff --git a/system/tcptest.py b/system/tcptest.py
index f1512b6..773ecbe 100755
--- a/system/tcptest.py
+++ b/system/tcptest.py
@@ -12,8 +12,8 @@ import threading
 from optparse import OptionParser    
 
 def myprint(message, id='client'):
-    now=time.strftime("%H:%M:%S", time.localtime())
-    print "*",now,'(%s)' % id, '--',message
+    now = time.strftime("%H:%M:%S", time.localtime())
+    print "* {now} ({id}) -- {message}".format(**locals())
     sys.stdout.flush()
 
 def show_network_status(id):
@@ -127,15 +127,15 @@ class Client:
             mout=i*'ping ' + '\n'
             min=mout.upper()
             if s.send(mout) != len(mout):
-                myprint("cannot send %s"%mout.strip())
+                myprint("cannot send {}".format(mout.strip()))
                 result=False
                 break
             line=s.recv(len(min))
             if line is not line:
-                myprint("unexpected reception\ngot:%s\nexpected: %s",line,min)
-                result=False
+                myprint("unexpected reception\ngot:{}\nexpected: {}".format(line, min))
+                result = False
             else:
-                myprint("OK:%s"%mout.strip())
+                myprint("OK:{}".format(mout.strip()))
             # leave the connection open, but the last one (so 1 iter returns fast)
             if i != options.loops:
                 time.sleep(options.sleep)
diff --git a/system/utils.py b/system/utils.py
index 701ad3f..8143b95 100644
--- a/system/utils.py
+++ b/system/utils.py
@@ -8,37 +8,39 @@ options={}
 
 def init_options(options_arg):
     global options
-    options=options_arg
+    options = options_arg
 
 # how could this accept a list again ?
 def header(message):
-    now=time.strftime("%H:%M:%S", time.localtime())
-    print "*",now,'--',message
+    now = time.strftime("%H:%M:%S", time.localtime())
+    print "*", now, '--', message
 
-def pprint(message,spec,depth=2):
-    now=time.strftime("%H:%M:%S", time.localtime())
-    print ">",now,"--",message
-    PrettyPrinter(indent=8,depth=depth).pprint(spec)
+def pprint(message, spec, depth=2):
+    now = time.strftime("%H:%M:%S", time.localtime())
+    print ">", now, "--", message
+    PrettyPrinter(indent=8, depth=depth).pprint(spec)
 
 
 
 def system(command, background=False, silent=False, dry_run=None):
     dry_run = dry_run if dry_run is not None else getattr(options, 'dry_run', False)
     if dry_run:
-        print 'dry_run:',command
+        print 'dry_run:', command
         return 0
     
     if silent :    
-        if command.find(';')>=0: command = "(%s) 2> /dev/null" % command
+        if command.find(';') >= 0:
+            command = "({}) 2> /dev/null".format(command)
         else: command += " 2> /dev/null"
-    if background: command += " &"
+    if background:
+        command += " &"
     if silent:
         print '.',
         sys.stdout.flush()
     else:
-        now=time.strftime("%H:%M:%S", time.localtime())
+        now = time.strftime("%H:%M:%S", time.localtime())
         # don't show in summary
-        print "->",now,'--',
+        print "->", now, '--',
         sys.stdout.flush()
     if not silent:
         command = "set -x; " + command
@@ -47,36 +49,38 @@ def system(command, background=False, silent=False, dry_run=None):
 ### WARNING : this ALWAYS does its job, even in dry_run mode
 def output_of (command):
     import commands
-    (code,string) = commands.getstatusoutput(command)
-    return (code,string)
+    (code, string) = commands.getstatusoutput(command)
+    return (code, string)
 
 
 # convenience: translating shell-like pattern into regexp
 def match (string, pattern):
     # tmp - there's probably much simpler
     # rewrite * into .*, ? into .
-    pattern=pattern.replace("*",".*")
-    pattern=pattern.replace("?",".")
+    pattern = pattern.replace("*",".*")
+    pattern = pattern.replace("?",".")
     return re.compile(pattern).match(string)
     
 def locate_hooks_scripts (message, path, extensions):
-    print message,'searching',path,'for extensions',extensions
-    scripts=[]
+    print message, 'searching', path, 'for extensions', extensions
+    scripts = []
     for ext in extensions:
         # skip helper programs
-        scripts += glob.glob (path+'/[a-zA-Z]*.'+ext)
+        scripts += glob.glob (path+'/[a-zA-Z]*.' + ext)
     return scripts
     
 # quick & dirty - should probably use the parseroption object instead
 # and move to TestMain as well
 exclude_options_keys = [ 'ensure_value' , 'read_file', 'read_module' ]
 def show_options (message, options):
-    now=time.strftime("%H:%M:%S", time.localtime())
-    print ">",now,"--",message
+    now = time.strftime("%H:%M:%S", time.localtime())
+    print ">", now, "--", message
     for k in dir(options):
-        if k.find("_")==0: continue
-        if k in exclude_options_keys: continue
-        print "    ",k,":",getattr(options,k)
+        if k.find("_") == 0:
+            continue
+        if k in exclude_options_keys:
+            continue
+        print "    ", k, ":", getattr(options, k)
 
 
 
-- 
2.43.0