+### this returns the kind of virtualization on the node
+# either 'vs' or 'lxc'
+# also caches it in /etc/planetlab/virt for next calls
+# could be promoted to core nm if need be
+virt_stamp="/etc/planetlab/virt"
+def get_node_virt ():
+ try:
+ return file(virt_stamp).read().strip()
+ except:
+ pass
+ logger.log("Computing virt..")
+ try:
+ if subprocess.call ([ 'vserver', '--help' ]) ==0: virt='vs'
+ else: virt='lxc'
+ except:
+ virt='lxc'
+ with file(virt_stamp,"w") as f:
+ f.write(virt)
+ return virt
+
+### this return True or False to indicate that systemctl is present on that box
+# cache result in memory as _has_systemctl
+_has_systemctl=None
+def has_systemctl ():
+ global _has_systemctl
+ if _has_systemctl is None:
+ _has_systemctl = (subprocess.call([ 'systemctl', '--help' ]) == 0)
+ return _has_systemctl
+
+# how to run a command in a slice
+# now this is a painful matter
+# the problem is with capsh that forces a bash command to be injected in its exec'ed command
+# so because lxcsu uses capsh, you cannot exec anything else than bash
+# bottom line is, what actually needs to be called is
+# vs: vserver exec slicename command and its arguments
+# lxc: lxcsu slicename "command and its arguments"
+# which, OK, is no big deal as long as the command is simple enough,
+# but do not stretch it with arguments that have spaces or need quoting as that will become a nightmare
+def command_in_slice (slicename, argv):
+ virt=get_node_virt()
+ if virt=='vs':
+ return [ 'vserver', slicename, 'exec', ] + argv
+ elif virt=='lxc':
+ # wrap up argv in a single string for -c
+ return [ 'lxcsu', slicename, ] + [ " ".join(argv) ]
+ logger.log("command_in_slice: WARNING: could not find a valid virt")
+ return argv
+
+####################
+def init_signals ():
+ def handler (signum, frame):
+ logger.log("Received signal %d - exiting"%signum)
+ os._exit(1)
+ signal.signal(signal.SIGHUP,handler)
+ signal.signal(signal.SIGQUIT,handler)
+ signal.signal(signal.SIGINT,handler)
+ signal.signal(signal.SIGTERM,handler)