Correct way to move kvm vm

Solution 1:

1. copy the VM's disks from /var/lib/libvirt/images on src host to the same dir on destination host
2. on the source host run virsh dumpxml VMNAME > domxml.xml and copy this xml to the destination host
3. on the destination host run virsh define domxml.xml

start the VM.

• If the disk location differs, you need to edit the xml's devices/disk node to point to the image on the destination host

• If the VM is attached to custom defined networks, you'll need to either edit them out of the xml on the destination host or redefine them as well

  1. On source machine virsh net-dumpxml NETNAME > netxml.xml
  2. copy netxml.xml to target machine
  3. On target machine virsh net-define netxml.xml && virsh net-start NETNAME & virsh net-autostart NETNAME)

Solution 2:

Since I can't comment yet, I have to post this addendum to dyasny's answer this way.

If the VM has snapshots that you want to preserve, you should dump the snapshot xml-files on the source with virsh snapshot-dumpxml $dom $name > file.xml for each snapshot in the snapshot list of the VM virsh snapshot-list --name $dom.

Then on the destination use virsh snapshot-create --redefine $dom file.xml to finish migrating the snapshots.

If you also care about which snapshot is the current one, then additionally do on the source:
virsh snapshot-current --name $dom
and on the destination:
virsh snapshot-current $dom $name

Then you can use virsh snapshot-delete --metadata $dom $name for each snapshot to delete the xml files on the source, or you could just delete them from /var/lib/libvirt/qemu/snapshots/$guestname

Sources:

1. libvirt-users mailing list

2. http://kashyapc.com/2012/09/14/externaland-live-snapshots-with-libvirt/

Solution 3:

Yes, just copying the XML file and the virtual disk images is sufficient, but this obviously precludes a "live" migration. The VM must be shut off during this procedure.

Once copied to the destination, libvirtd must be reloaded or restarted to recognize the new XML file.