I am having some problems getting libvirt under python to work properly. I can setup new domains by using the createLinux() function, but when I attempt to use defineXML() it fails with no reason given other then "virDomainDefineXML() failed". I am using the same XML file for both functions. This is on a Ubuntu 7.04 server running python 2.5 & libvirt 0.1.8 (from the ubuntu universe repo). Here is my test code: import libvirt import sys import xml import random try: conn = libvirt.open(None) except Exception, e: print e if conn == None: print 'Failed to open connection to the hypervisor' sys.exit(1) create = True if create: xmlfile = open('webserv.xml') xmldesc = xmlfile.read() xmlfile.close() try: # webserv = conn.createLinux(xmldesc, 0) webserv = conn.defineXML(xmldesc) except Exception, e: print 'Failed to create webserv: %s' % e sys.exit(1) if webserv is None: print 'whoops this shouldnt happen!' conn.create(webserv) try: print "Domain 0: id %d running %s" % (webserv.ID(), webserv.OSType()) print webserv.info() print webserv.XMLDesc(0) except Exception, e: print e #webserv.shutdown() And the XML file: <domain type='xen' > <name>webserv</name> <os> <type>linux</type> <kernel>/boot/vmlinuz-2.6.19-4-generic-amd64</kernel> <initrd>/boot/initrd.img-2.6.19-4-generic-amd64</initrd> <root>/dev/hda1</root> </os> <memory>1024</memory> <vcpu>1</vcpu> <on_poweroff>destroy</on_poweroff> <on_reboot>restart</on_reboot> <on_crash>restart</on_crash> <devices> <interface type='bridge'> <source bridge='xenbr0'/> <mac address='00:16:3e:24:27:a5'/> <script path='vif-bridge'/> </interface> <graphics type='vnc' port='5902'/> <disk type='file' device='disk'> <driver name='tap' type='aio'/> <source file='/virtual/images/webserv/webserv.img'/> <target dev='hda1'/> </disk> <console tty='/dev/pts/4'/> </devices> </domain> Am I missing something simple, or is there a bug? Thanks!