expose stack trace in error message when node is considered unresponsive

[nepi.git] / src / nepi / resources / linux / node.py

diff --git a/src/nepi/resources/linux/node.py b/src/nepi/resources/linux/node.py
index ff19bbb..0896ed0 100644 (file)
--- a/src/nepi/resources/linux/node.py
+++ b/src/nepi/resources/linux/node.py
@@ -3,9 +3,8 @@
 #    Copyright (C) 2013 INRIA
 #
 #    This program is free software: you can redistribute it and/or modify
 #    Copyright (C) 2013 INRIA
 #
 #    This program is free software: you can redistribute it and/or modify

-#    it under the terms of the GNU General Public License as published by
-#    the Free Software Foundation, either version 3 of the License, or
-#    (at your option) any later version.
+#    it under the terms of the GNU General Public License version 2 as
+#    published by the Free Software Foundation;

 #
 #    This program is distributed in the hope that it will be useful,
 #    but WITHOUT ANY WARRANTY; without even the implied warranty of
 #
 #    This program is distributed in the hope that it will be useful,
 #    but WITHOUT ANY WARRANTY; without even the implied warranty of


@@ -18,8 +17,8 @@
 # Author: Alina Quereilhac <alina.quereilhac@inria.fr>
 
 from nepi.execution.attribute import Attribute, Flags, Types
 # Author: Alina Quereilhac <alina.quereilhac@inria.fr>
 
 from nepi.execution.attribute import Attribute, Flags, Types

-from nepi.execution.resource import ResourceManager, clsinit_copy, \
-        ResourceState
+from nepi.execution.resource import (ResourceManager, clsinit_copy, 
+                                     ResourceState)

 from nepi.resources.linux import rpmfuncs, debfuncs 
 from nepi.util import sshfuncs, execfuncs
 from nepi.util.sshfuncs import ProcStatus
 from nepi.resources.linux import rpmfuncs, debfuncs 
 from nepi.util import sshfuncs, execfuncs
 from nepi.util.sshfuncs import ProcStatus


@@ -28,7 +27,6 @@ import collections
 import os
 import random
 import re
 import os
 import random
 import re

-import socket

 import tempfile
 import time
 import threading
 import tempfile
 import time
 import threading


@@ -51,12 +49,12 @@ class OSType:
     """
     Supported flavors of Linux OS
     """
     """
     Supported flavors of Linux OS
     """

-    FEDORA_8 = "f8"
-    FEDORA_12 = "f12"
-    FEDORA_14 = "f14"
-    FEDORA = "fedora"
-    UBUNTU = "ubuntu"
-    DEBIAN = "debian"
+    DEBIAN = 1 
+    UBUNTU = 1 << 1 
+    FEDORA = 1 << 2
+    FEDORA_8 = 1 << 3 | FEDORA 
+    FEDORA_12 = 1 << 4 | FEDORA 
+    FEDORA_14 = 1 << 5 | FEDORA 

 
 @clsinit_copy
 class LinuxNode(ResourceManager):
 
 @clsinit_copy
 class LinuxNode(ResourceManager):


@@ -149,69 +147,81 @@ class LinuxNode(ResourceManager):
 
     @classmethod
     def _register_attributes(cls):
 
     @classmethod
     def _register_attributes(cls):

-        hostname = Attribute("hostname", "Hostname of the machine",
-                flags = Flags.Design)
+        cls._register_attribute(Attribute(
+            "hostname", "Hostname of the machine",
+            flags = Flags.Design))

 
 

-        username = Attribute("username", "Local account username", 
-                flags = Flags.Credential)
+        cls._register_attribute(Attribute(
+            "username", "Local account username", 
+            flags = Flags.Credential))

 
 

-        port = Attribute("port", "SSH port", flags = Flags.Design)
+        cls._register_attribute(Attribute(
+            "port", "SSH port",
+            flags = Flags.Design))

         
         

-        home = Attribute("home",
-                "Experiment home directory to store all experiment related files",
-                flags = Flags.Design)
+        cls._register_attribute(Attribute(
+            "home",
+            "Experiment home directory to store all experiment related files",
+            flags = Flags.Design))

         
         

-        identity = Attribute("identity", "SSH identity file",
-                flags = Flags.Credential)
+        cls._register_attribute(Attribute(
+            "identity", "SSH identity file",
+            flags = Flags.Credential))

         
         

-        server_key = Attribute("serverKey", "Server public key", 
-                flags = Flags.Design)
+        cls._register_attribute(Attribute(
+            "serverKey", "Server public key", 
+            flags = Flags.Design))

         
         

-        clean_home = Attribute("cleanHome", "Remove all nepi files and directories "
-                " from node home folder before starting experiment", 
-                type = Types.Bool,
-                default = False,
-                flags = Flags.Design)
-
-        clean_experiment = Attribute("cleanExperiment", "Remove all files and directories " 
-                " from a previous same experiment, before the new experiment starts", 
-                type = Types.Bool,
-                default = False,
-                flags = Flags.Design)
+        cls._register_attribute(Attribute(
+            "cleanHome",
+            "Remove all nepi files and directories "
+            " from node home folder before starting experiment", 
+            type = Types.Bool,
+            default = False,
+            flags = Flags.Design))
+
+        cls._register_attribute(Attribute(
+            "cleanExperiment", "Remove all files and directories " 
+            " from a previous same experiment, before the new experiment starts", 
+            type = Types.Bool,
+            default = False,
+            flags = Flags.Design))

         
         

-        clean_processes = Attribute("cleanProcesses", 
-                "Kill all running processes before starting experiment",
-                type = Types.Bool,
-                default = False,
-                flags = Flags.Design)
+        cls._register_attribute(Attribute(
+            "cleanProcesses", 
+            "Kill all running processes before starting experiment",
+            type = Types.Bool,
+            default = False,
+            flags = Flags.Design))

         
         

-        tear_down = Attribute("tearDown", "Bash script to be executed before " + \
-                "releasing the resource",
-                flags = Flags.Design)
-
-        gateway_user = Attribute("gatewayUser", "Gateway account username",
-                flags = Flags.Design)
-
-        gateway = Attribute("gateway", "Hostname of the gateway machine",
-                flags = Flags.Design)
-
-        ip = Attribute("ip", "Linux host public IP address. "
-                   "Must not be modified by the user unless hostname is 'localhost'",
-                    flags = Flags.Design)
-
-        cls._register_attribute(hostname)
-        cls._register_attribute(username)
-        cls._register_attribute(port)
-        cls._register_attribute(home)
-        cls._register_attribute(identity)
-        cls._register_attribute(server_key)
-        cls._register_attribute(clean_home)
-        cls._register_attribute(clean_experiment)
-        cls._register_attribute(clean_processes)
-        cls._register_attribute(tear_down)
-        cls._register_attribute(gateway_user)
-        cls._register_attribute(gateway)
-        cls._register_attribute(ip)
+        cls._register_attribute(Attribute(
+            "cleanProcessesAfter", 
+            """Kill all running processes after starting experiment
+            This might be dangerous when using user root""",
+            type = Types.Bool,
+            default = True,
+            flags = Flags.Design))
+        
+        cls._register_attribute(Attribute(
+            "tearDown",
+            "Bash script to be executed before releasing the resource",
+            flags = Flags.Design))
+
+        cls._register_attribute(Attribute(
+            "gatewayUser",
+            "Gateway account username",
+            flags = Flags.Design))
+
+        cls._register_attribute(Attribute(
+            "gateway",
+            "Hostname of the gateway machine",
+            flags = Flags.Design))
+
+        cls._register_attribute(Attribute(
+            "ip",
+            "Linux host public IP address. "
+            "Must not be modified by the user unless hostname is 'localhost'",
+            flags = Flags.Design))

 
     def __init__(self, ec, guid):
         super(LinuxNode, self).__init__(ec, guid)
 
     def __init__(self, ec, guid):
         super(LinuxNode, self).__init__(ec, guid)


@@ -227,17 +237,17 @@ class LinuxNode(ResourceManager):
         # of a file or folder prior to its creation, and another 
         # application creating the same file or folder in between.
         self._node_lock = threading.Lock()
         # of a file or folder prior to its creation, and another 
         # application creating the same file or folder in between.
         self._node_lock = threading.Lock()

-    
+        

     def log_message(self, msg):
     def log_message(self, msg):

-        return " guid %d - host %s - %s " % (self.guid, 
-                self.get("hostname"), msg)
+        return " guid {} - host {} - {} "\
+            .format(self.guid, self.get("hostname"), msg)

 
     @property
     def home_dir(self):
         home = self.get("home") or ""
         if not home.startswith("/"):
 
     @property
     def home_dir(self):
         home = self.get("home") or ""
         if not home.startswith("/"):

-           home = os.path.join(self._home_dir, home) 
-        return home
+            home = os.path.join(self._home_dir, home) 
+            return home

 
     @property
     def nepi_home(self):
 
     @property
     def nepi_home(self):


@@ -273,7 +283,7 @@ class LinuxNode(ResourceManager):
 
     @property
     def node_home(self):
 
     @property
     def node_home(self):

-        return os.path.join(self.exp_home, "node-%d" % self.guid)
+        return os.path.join(self.exp_home, "node-{}".format(self.guid))

 
     @property
     def run_home(self):
 
     @property
     def run_home(self):


@@ -291,22 +301,22 @@ class LinuxNode(ResourceManager):
 
         out = self.get_os()
 
 
         out = self.get_os()
 

-        if out.find("Fedora release 8") == 0:
-            self._os = OSType.FEDORA_8
-        elif out.find("Fedora release 12") == 0:
-            self._os = OSType.FEDORA_12
-        elif out.find("Fedora release 14") == 0:
-            self._os = OSType.FEDORA_14
-        elif out.find("Fedora release") == 0:
-            self._os = OSType.FEDORA
-        elif out.find("Debian") == 0: 
+        if out.find("Debian") == 0: 

             self._os = OSType.DEBIAN
         elif out.find("Ubuntu") ==0:
             self._os = OSType.UBUNTU
             self._os = OSType.DEBIAN
         elif out.find("Ubuntu") ==0:
             self._os = OSType.UBUNTU

+        elif out.find("Fedora release") == 0:
+            self._os = OSType.FEDORA
+            if out.find("Fedora release 8") == 0:
+                self._os = OSType.FEDORA_8
+            elif out.find("Fedora release 12") == 0:
+                self._os = OSType.FEDORA_12
+            elif out.find("Fedora release 14") == 0:
+                self._os = OSType.FEDORA_14

         else:
             msg = "Unsupported OS"
             self.error(msg, out)
         else:
             msg = "Unsupported OS"
             self.error(msg, out)

-            raise RuntimeError, "%s - %s " %( msg, out )
+            raise RuntimeError("{} - {} ".format(msg, out))

 
         return self._os
 
 
         return self._os
 


@@ -318,23 +328,22 @@ class LinuxNode(ResourceManager):
         out = ""
         try:
             (out, err), proc = self.execute("cat /etc/issue", 
         out = ""
         try:
             (out, err), proc = self.execute("cat /etc/issue", 

-                    with_lock = True,
-                    blocking = True)
+                                            with_lock = True,
+                                            blocking = True)

         except:
             trace = traceback.format_exc()
         except:
             trace = traceback.format_exc()

-            msg = "Error detecting OS: %s " % trace
+            msg = "Error detecting OS: {} ".format(trace)

             self.error(msg, out, err)
             self.error(msg, out, err)

-        
+    

         return out
 
     @property
     def use_deb(self):
         return out
 
     @property
     def use_deb(self):

-        return self.os in [OSType.DEBIAN, OSType.UBUNTU]
+        return (self.os & (OSType.DEBIAN|OSType.UBUNTU))

 
     @property
     def use_rpm(self):
 
     @property
     def use_rpm(self):

-        return self.os in [OSType.FEDORA_12, OSType.FEDORA_14, OSType.FEDORA_8,
-                OSType.FEDORA]
+        return (self.os & OSType.FEDORA)

 
     @property
     def localhost(self):
 
     @property
     def localhost(self):


@@ -343,7 +352,8 @@ class LinuxNode(ResourceManager):
     def do_provision(self):
         # check if host is alive
         if not self.is_alive():
     def do_provision(self):
         # check if host is alive
         if not self.is_alive():

-            msg = "Deploy failed. Unresponsive node %s" % self.get("hostname")
+            trace = traceback.format_exc()
+            msg = "Deploy failed. Unresponsive node {} -- traceback {}".format(self.get("hostname"), trace)

             self.error(msg)
             raise RuntimeError, msg
 
             self.error(msg)
             raise RuntimeError, msg
 


@@ -354,33 +364,28 @@ class LinuxNode(ResourceManager):
 
         if self.get("cleanHome"):
             self.clean_home()
 
         if self.get("cleanHome"):
             self.clean_home()

- 
+            

         if self.get("cleanExperiment"):
             self.clean_experiment()
         if self.get("cleanExperiment"):
             self.clean_experiment()

-    
+            

         # Create shared directory structure and node home directory
         paths = [self.lib_dir, 
         # Create shared directory structure and node home directory
         paths = [self.lib_dir, 

-            self.bin_dir, 
-            self.src_dir, 
-            self.share_dir, 
-            self.node_home]
+                 self.bin_dir, 
+                 self.src_dir, 
+                 self.share_dir, 
+                 self.node_home]

 
         self.mkdir(paths)
 
         # Get Public IP address if possible
         if not self.get("ip"):
 
         self.mkdir(paths)
 
         # Get Public IP address if possible
         if not self.get("ip"):

-            ip = None
-
-            if self.localhost:
-                ip = socket.gethostbyname(socket.gethostname())
-            else:
-                try:
-                    ip = socket.gethostbyname(self.get("hostname"))
-                except:
-                    msg = "DNS can not resolve hostname %s" % self.get("hostname") 
-                    self.debug(msg)
-
-            self.set("ip", ip)
+            try:
+                ip = sshfuncs.gethostbyname(self.get("hostname"))
+                self.set("ip", ip)
+            except:
+                if self.get("gateway") is None:
+                    msg = "Local DNS can not resolve hostname {}".format(self.get("hostname"))
+                    self.error(msg)

 
         super(LinuxNode, self).do_provision()
 
 
         super(LinuxNode, self).do_provision()
 


@@ -414,7 +419,8 @@ class LinuxNode(ResourceManager):
         if tear_down:
             self.execute(tear_down)
 
         if tear_down:
             self.execute(tear_down)
 

-        self.clean_processes()
+        if self.get("cleanProcessesAfter"):
+            self.clean_processes()

 
         super(LinuxNode, self).do_release()
 
 
         super(LinuxNode, self).do_release()
 


@@ -430,7 +436,8 @@ class LinuxNode(ResourceManager):
         
         if self.get("username") != 'root':
             cmd = ("sudo -S killall tcpdump || /bin/true ; " +
         
         if self.get("username") != 'root':
             cmd = ("sudo -S killall tcpdump || /bin/true ; " +

-                "sudo -S killall -u %s || /bin/true ; " % self.get("username"))
+                   "sudo -S kill -9 $(ps aux | grep '[.]nepi' | awk '{print $2}') || /bin/true ; " +
+                   "sudo -S killall -u {} || /bin/true ; ".format(self.get("username")))

         else:
             if self.state >= ResourceState.READY:
                 import pickle
         else:
             if self.state >= ResourceState.READY:
                 import pickle


@@ -446,14 +453,14 @@ class LinuxNode(ResourceManager):
                     kill_pids = ' '.join(dict(kill_pids).keys())
 
                     cmd = ("killall tcpdump || /bin/true ; " +
                     kill_pids = ' '.join(dict(kill_pids).keys())
 
                     cmd = ("killall tcpdump || /bin/true ; " +

-                        "kill $(ps aux | grep '[n]epi' | awk '{print $2}') || /bin/true ; " +
-                        "kill %s || /bin/true ; " % kill_pids)
+                           "kill $(ps aux | grep '[.]nepi' | awk '{print $2}') || /bin/true ; " +
+                           "kill {} || /bin/true ; ".format(kill_pids))

                 else:
                     cmd = ("killall tcpdump || /bin/true ; " +
                 else:
                     cmd = ("killall tcpdump || /bin/true ; " +

-                        "kill $(ps aux | grep '[n]epi' | awk '{print $2}') || /bin/true ; ")
+                           "kill $(ps aux | grep '[.]nepi' | awk '{print $2}') || /bin/true ; ")

             else:
                 cmd = ("killall tcpdump || /bin/true ; " +
             else:
                 cmd = ("killall tcpdump || /bin/true ; " +

-                    "kill $(ps aux | grep '[n]epi' | awk '{print $2}') || /bin/true ; ")
+                       "kill $(ps aux | grep '[.]nepi' | awk '{print $2}') || /bin/true ; ")

 
         (out, err), proc = self.execute(cmd, retry = 1, with_lock = True)
 
 
         (out, err), proc = self.execute(cmd, retry = 1, with_lock = True)
 


@@ -462,8 +469,8 @@ class LinuxNode(ResourceManager):
         """
         self.info("Cleaning up home")
         
         """
         self.info("Cleaning up home")
         

-        cmd = "cd %s ; find . -maxdepth 1 -name \.nepi -execdir rm -rf {} + " % (
-                self.home_dir )
+        cmd = "cd {} ; find . -maxdepth 1 -name \.nepi -execdir rm -rf {{}} + "\
+              .format(self.home_dir)

 
         return self.execute(cmd, with_lock = True)
 
 
         return self.execute(cmd, with_lock = True)
 


@@ -474,33 +481,33 @@ class LinuxNode(ResourceManager):
         """
         self.info("Cleaning up experiment files")
         
         """
         self.info("Cleaning up experiment files")
         

-        cmd = "cd %s ; find . -maxdepth 1 -name '%s' -execdir rm -rf {} + " % (
-                self.exp_dir,
-                self.ec.exp_id )
-            
+        cmd = "cd {} ; find . -maxdepth 1 -name '{}' -execdir rm -rf {{}} + "\
+              .format(self.exp_dir, self.ec.exp_id)
+        

         return self.execute(cmd, with_lock = True)
 
     def execute(self, command,
         return self.execute(cmd, with_lock = True)
 
     def execute(self, command,

-            sudo = False,
-            env = None,
-            tty = False,
-            forward_x11 = False,
-            retry = 3,
-            connect_timeout = 30,
-            strict_host_checking = False,
-            persistent = True,
-            blocking = True,
-            with_lock = False
-            ):
+                sudo = False,
+                env = None,
+                tty = False,
+                forward_x11 = False,
+                retry = 3,
+                connect_timeout = 30,
+                strict_host_checking = False,
+                persistent = True,
+                blocking = True,
+                with_lock = False
+    ):

         """ Notice that this invocation will block until the
         execution finishes. If this is not the desired behavior,
         use 'run' instead."""
 
         if self.localhost:
         """ Notice that this invocation will block until the
         execution finishes. If this is not the desired behavior,
         use 'run' instead."""
 
         if self.localhost:

-            (out, err), proc = execfuncs.lexec(command, 
-                    user = self.get("username"), # still problem with localhost
-                    sudo = sudo,
-                    env = env)
+            (out, err), proc = execfuncs.lexec(
+                command, 
+                user = self.get("username"), # still problem with localhost
+                sudo = sudo,
+                env = env)

         else:
             if with_lock:
                 # If the execute command is blocking, we don't want to keep
         else:
             if with_lock:
                 # If the execute command is blocking, we don't want to keep


@@ -527,7 +534,7 @@ class LinuxNode(ResourceManager):
                         persistent = persistent,
                         blocking = blocking, 
                         strict_host_checking = strict_host_checking
                         persistent = persistent,
                         blocking = blocking, 
                         strict_host_checking = strict_host_checking

-                        )
+                    )

             else:
                 (out, err), proc = sshfuncs.rexec(
                     command, 
             else:
                 (out, err), proc = sshfuncs.rexec(
                     command, 


@@ -548,7 +555,7 @@ class LinuxNode(ResourceManager):
                     persistent = persistent,
                     blocking = blocking, 
                     strict_host_checking = strict_host_checking
                     persistent = persistent,
                     blocking = blocking, 
                     strict_host_checking = strict_host_checking

-                    )
+                )

 
         return (out, err), proc
 
 
         return (out, err), proc
 


@@ -562,16 +569,17 @@ class LinuxNode(ResourceManager):
             tty = False,
             strict_host_checking = False):
         
             tty = False,
             strict_host_checking = False):
         

-        self.debug("Running command '%s'" % command)
+        self.debug("Running command '{}'".format(command))

         
         if self.localhost:
         
         if self.localhost:

-            (out, err), proc = execfuncs.lspawn(command, pidfile,
-                    home = home, 
-                    create_home = create_home, 
-                    stdin = stdin or '/dev/null',
-                    stdout = stdout or '/dev/null',
-                    stderr = stderr or '/dev/null',
-                    sudo = sudo) 
+            (out, err), proc = execfuncs.lspawn(
+                command, pidfile,
+                home = home, 
+                create_home = create_home, 
+                stdin = stdin or '/dev/null',
+                stdout = stdout or '/dev/null',
+                stderr = stderr or '/dev/null',
+                sudo = sudo) 

         else:
             with self._node_lock:
                 (out, err), proc = sshfuncs.rspawn(
         else:
             with self._node_lock:
                 (out, err), proc = sshfuncs.rspawn(


@@ -593,7 +601,7 @@ class LinuxNode(ResourceManager):
                     server_key = self.get("serverKey"),
                     tty = tty,
                     strict_host_checking = strict_host_checking
                     server_key = self.get("serverKey"),
                     tty = tty,
                     strict_host_checking = strict_host_checking

-                    )
+                )

 
         return (out, err), proc
 
 
         return (out, err), proc
 


@@ -613,7 +621,7 @@ class LinuxNode(ResourceManager):
                     identity = self.get("identity"),
                     server_key = self.get("serverKey"),
                     strict_host_checking = False
                     identity = self.get("identity"),
                     server_key = self.get("serverKey"),
                     strict_host_checking = False

-                    )
+                )

         
         return pidtuple
 
         
         return pidtuple
 


@@ -623,17 +631,17 @@ class LinuxNode(ResourceManager):
         else:
             with self._node_lock:
                 status = sshfuncs.rstatus(
         else:
             with self._node_lock:
                 status = sshfuncs.rstatus(

-                        pid, ppid,
-                        host = self.get("hostname"),
-                        user = self.get("username"),
-                        port = self.get("port"),
-                        gwuser = self.get("gatewayUser"),
-                        gw = self.get("gateway"),
-                        agent = True,
-                        identity = self.get("identity"),
-                        server_key = self.get("serverKey"),
-                        strict_host_checking = False
-                        )
+                    pid, ppid,
+                    host = self.get("hostname"),
+                    user = self.get("username"),
+                    port = self.get("port"),
+                    gwuser = self.get("gatewayUser"),
+                    gw = self.get("gateway"),
+                    agent = True,
+                    identity = self.get("identity"),
+                    server_key = self.get("serverKey"),
+                    strict_host_checking = False
+                )

            
         return status
     
            
         return status
     


@@ -659,14 +667,15 @@ class LinuxNode(ResourceManager):
                         identity = self.get("identity"),
                         server_key = self.get("serverKey"),
                         strict_host_checking = False
                         identity = self.get("identity"),
                         server_key = self.get("serverKey"),
                         strict_host_checking = False

-                        )
+                    )

 
         return (out, err), proc
 
     def copy(self, src, dst):
         if self.localhost:
 
         return (out, err), proc
 
     def copy(self, src, dst):
         if self.localhost:

-            (out, err), proc = execfuncs.lcopy(src, dst, 
-                    recursive = True)
+            (out, err), proc = execfuncs.lcopy(
+                src, dst, 
+                recursive = True)

         else:
             with self._node_lock:
                 (out, err), proc = sshfuncs.rcopy(
         else:
             with self._node_lock:
                 (out, err), proc = sshfuncs.rcopy(


@@ -682,7 +691,7 @@ class LinuxNode(ResourceManager):
         return (out, err), proc
 
     def upload(self, src, dst, text = False, overwrite = True,
         return (out, err), proc
 
     def upload(self, src, dst, text = False, overwrite = True,

-            raise_on_error = True):
+               raise_on_error = True):

         """ Copy content to destination
 
         src  string with the content to copy. Can be:
         """ Copy content to destination
 
         src  string with the content to copy. Can be:


@@ -719,7 +728,7 @@ class LinuxNode(ResourceManager):
 
         if not self.localhost:
             # Build destination as <user>@<server>:<path>
 
         if not self.localhost:
             # Build destination as <user>@<server>:<path>

-            dst = "%s@%s:%s" % (self.get("username"), self.get("hostname"), dst)
+            dst = "{}@{}:{}".format(self.get("username"), self.get("hostname"), dst)

 
         ((out, err), proc) = self.copy(src, dst)
 
 
         ((out, err), proc) = self.copy(src, dst)
 


@@ -728,10 +737,10 @@ class LinuxNode(ResourceManager):
             os.remove(f.name)
 
         if err:
             os.remove(f.name)
 
         if err:

-            msg = " Failed to upload files - src: %s dst: %s" %  (";".join(src), dst) 
+            msg = " Failed to upload files - src: {} dst: {}".format(";".join(src), dst)

             self.error(msg, out, err)
             
             self.error(msg, out, err)
             

-            msg = "%s out: %s err: %s" % (msg, out, err)
+            msg = "{} out: {} err: {}".format(msg, out, err)

             if raise_on_error:
                 raise RuntimeError, msg
 
             if raise_on_error:
                 raise RuntimeError, msg
 


@@ -740,12 +749,12 @@ class LinuxNode(ResourceManager):
     def download(self, src, dst, raise_on_error = True):
         if not self.localhost:
             # Build destination as <user>@<server>:<path>
     def download(self, src, dst, raise_on_error = True):
         if not self.localhost:
             # Build destination as <user>@<server>:<path>

-            src = "%s@%s:%s" % (self.get("username"), self.get("hostname"), src)
+            src = "{}@{}:{}".format(self.get("username"), self.get("hostname"), src)

 
         ((out, err), proc) = self.copy(src, dst)
 
         if err:
 
         ((out, err), proc) = self.copy(src, dst)
 
         if err:

-            msg = " Failed to download files - src: %s dst: %s" %  (";".join(src), dst) 
+            msg = " Failed to download files - src: {} dst: {}".format(";".join(src), dst) 

             self.error(msg, out, err)
 
             if raise_on_error:
             self.error(msg, out, err)
 
             if raise_on_error:


@@ -766,8 +775,9 @@ class LinuxNode(ResourceManager):
 
         return command
 
 
         return command
 

-    def install_packages(self, packages, home, run_home = None,
-            raise_on_error = True):
+    def install_packages(self, packages, home,
+                         run_home = None,
+                         raise_on_error = True):

         """ Install packages in the Linux host.
 
         'home' is the directory to upload the package installation script.
         """ Install packages in the Linux host.
 
         'home' is the directory to upload the package installation script.


@@ -778,18 +788,18 @@ class LinuxNode(ResourceManager):
         run_home = run_home or home
 
         (out, err), proc = self.run_and_wait(command, run_home, 
         run_home = run_home or home
 
         (out, err), proc = self.run_and_wait(command, run_home, 

-            shfile = os.path.join(home, "instpkg.sh"),
-            pidfile = "instpkg_pidfile",
-            ecodefile = "instpkg_exitcode",
-            stdout = "instpkg_stdout", 
-            stderr = "instpkg_stderr",
-            overwrite = False,
-            raise_on_error = raise_on_error)
+                                             shfile = os.path.join(home, "instpkg.sh"),
+                                             pidfile = "instpkg_pidfile",
+                                             ecodefile = "instpkg_exitcode",
+                                             stdout = "instpkg_stdout", 
+                                             stderr = "instpkg_stderr",
+                                             overwrite = False,
+                                             raise_on_error = raise_on_error)

 
         return (out, err), proc 
 
     def remove_packages(self, packages, home, run_home = None,
 
         return (out, err), proc 
 
     def remove_packages(self, packages, home, run_home = None,

-            raise_on_error = True):
+                        raise_on_error = True):

         """ Uninstall packages from the Linux host.
 
         'home' is the directory to upload the package un-installation script.
         """ Uninstall packages from the Linux host.
 
         'home' is the directory to upload the package un-installation script.


@@ -807,14 +817,14 @@ class LinuxNode(ResourceManager):
         run_home = run_home or home
 
         (out, err), proc = self.run_and_wait(command, run_home, 
         run_home = run_home or home
 
         (out, err), proc = self.run_and_wait(command, run_home, 

-            shfile = os.path.join(home, "rmpkg.sh"),
-            pidfile = "rmpkg_pidfile",
-            ecodefile = "rmpkg_exitcode",
-            stdout = "rmpkg_stdout", 
-            stderr = "rmpkg_stderr",
-            overwrite = False,
-            raise_on_error = raise_on_error)
-         
+                                             shfile = os.path.join(home, "rmpkg.sh"),
+                                             pidfile = "rmpkg_pidfile",
+                                             ecodefile = "rmpkg_exitcode",
+                                             stdout = "rmpkg_stdout", 
+                                             stderr = "rmpkg_stderr",
+                                             overwrite = False,
+                                             raise_on_error = raise_on_error)
+        

         return (out, err), proc 
 
     def mkdir(self, paths, clean = False):
         return (out, err), proc 
 
     def mkdir(self, paths, clean = False):


@@ -827,7 +837,7 @@ class LinuxNode(ResourceManager):
         if isinstance(paths, str):
             paths = [paths]
 
         if isinstance(paths, str):
             paths = [paths]
 

-        cmd = " ; ".join(map(lambda path: "mkdir -p %s" % path, paths))
+        cmd = " ; ".join(["mkdir -p {}".format(path) for path in paths])

 
         return self.execute(cmd, with_lock = True)
 
 
         return self.execute(cmd, with_lock = True)
 


@@ -839,23 +849,23 @@ class LinuxNode(ResourceManager):
         if isinstance(paths, str):
             paths = [paths]
 
         if isinstance(paths, str):
             paths = [paths]
 

-        cmd = " ; ".join(map(lambda path: "rm -rf %s" % path, paths))
+        cmd = " ; ".join(map(lambda path: "rm -rf {}".format(path), paths))

 
         return self.execute(cmd, with_lock = True)
 
         return self.execute(cmd, with_lock = True)

-        
+    

     def run_and_wait(self, command, home, 
     def run_and_wait(self, command, home, 

-            shfile="cmd.sh",
-            env=None,
-            overwrite=True,
-            wait_run=True,
-            pidfile="pidfile", 
-            ecodefile="exitcode", 
-            stdin=None, 
-            stdout="stdout", 
-            stderr="stderr", 
-            sudo=False,
-            tty=False,
-            raise_on_error=True):
+                     shfile="cmd.sh",
+                     env=None,
+                     overwrite=True,
+                     wait_run=True,
+                     pidfile="pidfile", 
+                     ecodefile="exitcode", 
+                     stdin=None, 
+                     stdout="stdout", 
+                     stderr="stderr", 
+                     sudo=False,
+                     tty=False,
+                     raise_on_error=True):

         """
         Uploads the 'command' to a bash script in the host.
         Then runs the script detached in background in the host, and
         """
         Uploads the 'command' to a bash script in the host.
         Then runs the script detached in background in the host, and


@@ -866,45 +876,45 @@ class LinuxNode(ResourceManager):
             shfile = os.path.join(home, shfile)
 
         self.upload_command(command, 
             shfile = os.path.join(home, shfile)
 
         self.upload_command(command, 

-            shfile = shfile, 
-            ecodefile = ecodefile, 
-            env = env,
-            overwrite = overwrite)
+                            shfile = shfile, 
+                            ecodefile = ecodefile, 
+                            env = env,
+                            overwrite = overwrite)

 
 

-        command = "bash %s" % shfile
+        command = "bash {}".format(shfile)

         # run command in background in remote host
         (out, err), proc = self.run(command, home, 
         # run command in background in remote host
         (out, err), proc = self.run(command, home, 

-                pidfile = pidfile,
-                stdin = stdin, 
-                stdout = stdout, 
-                stderr = stderr, 
-                sudo = sudo,
-                tty = tty)
+                                    pidfile = pidfile,
+                                    stdin = stdin, 
+                                    stdout = stdout, 
+                                    stderr = stderr, 
+                                    sudo = sudo,
+                                    tty = tty)

 
         # check no errors occurred
         if proc.poll():
 
         # check no errors occurred
         if proc.poll():

-            msg = " Failed to run command '%s' " % command
+            msg = " Failed to run command '{}' ".format(command)

             self.error(msg, out, err)
             if raise_on_error:
                 raise RuntimeError, msg
 
         # Wait for pid file to be generated
         pid, ppid = self.wait_pid(
             self.error(msg, out, err)
             if raise_on_error:
                 raise RuntimeError, msg
 
         # Wait for pid file to be generated
         pid, ppid = self.wait_pid(

-                home = home, 
-                pidfile = pidfile, 
-                raise_on_error = raise_on_error)
+            home = home, 
+            pidfile = pidfile, 
+            raise_on_error = raise_on_error)

 
         if wait_run:
             # wait until command finishes to execute
             self.wait_run(pid, ppid)
 
         if wait_run:
             # wait until command finishes to execute
             self.wait_run(pid, ppid)

-          
+            

             (eout, err), proc = self.check_errors(home,
             (eout, err), proc = self.check_errors(home,

-                ecodefile = ecodefile,
-                stderr = stderr)
+                                                  ecodefile = ecodefile,
+                                                  stderr = stderr)

 
             # Out is what was written in the stderr file
             if err:
 
             # Out is what was written in the stderr file
             if err:

-                msg = " Failed to run command '%s' " % command
+                msg = " Failed to run command '{}' ".format(command)

                 self.error(msg, eout, err)
 
                 if raise_on_error:
                 self.error(msg, eout, err)
 
                 if raise_on_error:


@@ -937,22 +947,20 @@ class LinuxNode(ResourceManager):
         return ExitCode.ERROR
 
     def upload_command(self, command, 
         return ExitCode.ERROR
 
     def upload_command(self, command, 

-            shfile="cmd.sh",
-            ecodefile="exitcode",
-            overwrite=True,
-            env=None):
+                       shfile="cmd.sh",
+                       ecodefile="exitcode",
+                       overwrite=True,
+                       env=None):

         """ Saves the command as a bash script file in the remote host, and
         forces to save the exit code of the command execution to the ecodefile
         """
 
         if not (command.strip().endswith(";") or command.strip().endswith("&")):
             command += ";"
         """ Saves the command as a bash script file in the remote host, and
         forces to save the exit code of the command execution to the ecodefile
         """
 
         if not (command.strip().endswith(";") or command.strip().endswith("&")):
             command += ";"

-      
+            

         # The exit code of the command will be stored in ecodefile
         # The exit code of the command will be stored in ecodefile

-        command = " { %(command)s } ; echo $? > %(ecodefile)s ;" % {
-                'command': command,
-                'ecodefile': ecodefile,
-                } 
+        command = " {{ {command} }} ; echo $? > {ecodefile} ;"\
+                  .format(command=command, ecodefile=ecodefile)

 
         # Export environment
         environ = self.format_environment(env)
 
         # Export environment
         environ = self.format_environment(env)


@@ -974,11 +982,11 @@ class LinuxNode(ResourceManager):
         env = re.sub(r'\s+', ' ', env.strip())
 
         sep = ";" if inline else "\n"
         env = re.sub(r'\s+', ' ', env.strip())
 
         sep = ";" if inline else "\n"

-        return sep.join(map(lambda e: " export %s" % e, env.split(" "))) + sep 
+        return sep.join([" export {}".format(e) for e in env.split(" ")]) + sep 

 
     def check_errors(self, home, 
 
     def check_errors(self, home, 

-            ecodefile = "exitcode", 
-            stderr = "stderr"):
+                     ecodefile = "exitcode", 
+                     stderr = "stderr"):

         """ Checks whether errors occurred while running a command.
         It first checks the exit code for the command, and only if the
         exit code is an error one it returns the error output.
         """ Checks whether errors occurred while running a command.
         It first checks the exit code for the command, and only if the
         exit code is an error one it returns the error output.


@@ -991,7 +999,7 @@ class LinuxNode(ResourceManager):
         ecode = self.exitcode(home, ecodefile)
 
         if ecode in [ ExitCode.CORRUPTFILE, ExitCode.ERROR ]:
         ecode = self.exitcode(home, ecodefile)
 
         if ecode in [ ExitCode.CORRUPTFILE, ExitCode.ERROR ]:

-            err = "Error retrieving exit code status from file %s/%s" % (home, ecodefile)
+            err = "Error retrieving exit code status from file {}/{}".format(home, ecodefile)

         elif ecode > 0 or ecode == ExitCode.FILENOTFOUND:
             # The process returned an error code or didn't exist. 
             # Check standard error.
         elif ecode > 0 or ecode == ExitCode.FILENOTFOUND:
             # The process returned an error code or didn't exist. 
             # Check standard error.


@@ -1002,9 +1010,9 @@ class LinuxNode(ResourceManager):
             # (cat returns 1 for error "No such file or directory")
             if ecode == ExitCode.FILENOTFOUND and proc.poll() == 1: 
                 err = "" 
             # (cat returns 1 for error "No such file or directory")
             if ecode == ExitCode.FILENOTFOUND and proc.poll() == 1: 
                 err = "" 

-            
+                

         return ("", err), proc
         return ("", err), proc

- 
+    

     def wait_pid(self, home, pidfile = "pidfile", raise_on_error = False):
         """ Waits until the pid file for the command is generated, 
             and returns the pid and ppid of the process """
     def wait_pid(self, home, pidfile = "pidfile", raise_on_error = False):
         """ Waits until the pid file for the command is generated, 
             and returns the pid and ppid of the process """


@@ -1021,10 +1029,9 @@ class LinuxNode(ResourceManager):
                 time.sleep(delay)
                 delay = delay * 1.5
         else:
                 time.sleep(delay)
                 delay = delay * 1.5
         else:

-            msg = " Failed to get pid for pidfile %s/%s " % (
-                    home, pidfile )
+            msg = " Failed to get pid for pidfile {}/{} ".format(home, pidfile )

             self.error(msg)
             self.error(msg)

-            
+    

             if raise_on_error:
                 raise RuntimeError, msg
 
             if raise_on_error:
                 raise RuntimeError, msg
 


@@ -1052,8 +1059,8 @@ class LinuxNode(ResourceManager):
 
     def check_output(self, home, filename):
         """ Retrives content of file """
 
     def check_output(self, home, filename):
         """ Retrives content of file """

-        (out, err), proc = self.execute("cat %s" % 
-            os.path.join(home, filename), retry = 1, with_lock = True)
+        (out, err), proc = self.execute(
+            "cat {}".format(os.path.join(home, filename)), retry = 1, with_lock = True)

         return (out, err), proc
 
     def is_alive(self):
         return (out, err), proc
 
     def is_alive(self):


@@ -1071,20 +1078,21 @@ class LinuxNode(ResourceManager):
         # until the result is not empty string
         try:
             (out, err), proc = self.execute("echo 'ALIVE'",
         # until the result is not empty string
         try:
             (out, err), proc = self.execute("echo 'ALIVE'",

-                    blocking = True,
-                    with_lock = True)
-    
+                                            blocking = True,
+                                            with_lock = True)
+            

             if out.find("ALIVE") > -1:
                 return True
         except:
             trace = traceback.format_exc()
             if out.find("ALIVE") > -1:
                 return True
         except:
             trace = traceback.format_exc()

-            msg = "Unresponsive host. Error reaching host: %s " % trace
+            msg = "Unresponsive host. Error reaching host: {} ".format(trace)

 
         self.error(msg, out, err)
         return False
 
     def find_home(self):
 
         self.error(msg, out, err)
         return False
 
     def find_home(self):

-        """ Retrieves host home directory
+        """ 
+        Retrieves host home directory

         """
         # The underlying SSH layer will sometimes return an empty
         # output (even if the command was executed without errors).
         """
         # The underlying SSH layer will sometimes return an empty
         # output (even if the command was executed without errors).


@@ -1093,14 +1101,14 @@ class LinuxNode(ResourceManager):
         msg = "Impossible to retrieve HOME directory"
         try:
             (out, err), proc = self.execute("echo ${HOME}",
         msg = "Impossible to retrieve HOME directory"
         try:
             (out, err), proc = self.execute("echo ${HOME}",

-                    blocking = True,
-                    with_lock = True)
-    
+                                            blocking = True,
+                                            with_lock = True)
+            

             if out.strip() != "":
                 self._home_dir =  out.strip()
         except:
             trace = traceback.format_exc()
             if out.strip() != "":
                 self._home_dir =  out.strip()
         except:
             trace = traceback.format_exc()

-            msg = "Impossible to retrieve HOME directory %s" % trace
+            msg = "Impossible to retrieve HOME directory {}".format(trace)

 
         if not self._home_dir:
             self.error(msg)
 
         if not self._home_dir:
             self.error(msg)


@@ -1110,17 +1118,17 @@ class LinuxNode(ResourceManager):
         """ Removes files that already exist in the Linux host from src list
         """
         # construct a dictionary with { dst: src }
         """ Removes files that already exist in the Linux host from src list
         """
         # construct a dictionary with { dst: src }

-        dests = dict(map(lambda s: (os.path.join(dst, os.path.basename(s)), s), src)) \
-                    if len(src) > 1 else dict({dst: src[0]})
+        dests = { os.path.join(dst, os.path.basename(s)) : s for s in src } \
+                if len(src) > 1 else {dst: src[0]}

 
         command = []
         for d in dests.keys():
 
         command = []
         for d in dests.keys():

-            command.append(" [ -f %(dst)s ] && echo '%(dst)s' " % {'dst' : d} )
+            command.append(" [ -f {dst} ] && echo '{dst}' ".format(dst=d) )

 
         command = ";".join(command)
 
         (out, err), proc = self.execute(command, retry = 1, with_lock = True)
 
         command = ";".join(command)
 
         (out, err), proc = self.execute(command, retry = 1, with_lock = True)

-    
+        

         for d in dests.keys():
             if out.find(d) > -1:
                 del dests[d]
         for d in dests.keys():
             if out.find(d) > -1:
                 del dests[d]