In order to speed up some of my scripts I've implemented threading using python. Some scripts now run in 1/10th the time they used to as a result. Here I will try to illustrate some of the key points, hopefully it will be useful to anyone.
#!/usr/bin/python import sys import subprocess from threading import Thread class MyThread(Thread): def __init__(self,server,cmd): Thread.__init__(self) self.server = server self.cmd = cmd self.status = -1 def run(self): proc = subprocess.Popen('ssh %s %s' % (self.server,self.cmd), shell=True, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, ) self.stdout, self.stderr = proc.communicate() servers = ['shell1.example.net','ssh2.mhost.com','examplebox.net'] command = 'uptime' cmdlist =  for srv in servers: run = MyThread(srv,command) cmdlist.append(run) run.start() for c in cmdlist: c.join() print "### %s:n%s" % (c.server,c.stdout), print "## Done"
In my example we loop through servers and for each server we run the specified command on them, in their own thread! 3 servers in the above example, not a big deal, what if you have 20 servers? 40 servers? huge speed improvement.
The script can be easily extended to say... read the servers list in from a configuration file, or accept the 'command' from the command line arguments, (argv[1:]) etc.