How to migrate guests using virsh commands?

Usually "xm migrate -l" is used to migrate a guest from one system to other system. There is no option in virt-manager to migrate a guest from one host to another. Libvirt based virsh command can be used to do this. The syntax of "virsh migrate" is a bit confusing to a lot of beginners. Details given below would help in solving those confusions.

- There are two systems - HostA and HostB. HostA is the source machine and HostB is the destination machine.

1 - If you are currently logged into HostA as root, below command can be used to migrate a guest to HostB.

# virsh migrate --live xen+ssh://HostB

Replace HostB with its ip or FQDN. You would be asked for the root password of HostB. Upon entering the right password for HostB, migration would happen successfully.

2 - If you are currently logged into a third system in the network which has "virsh" command available in it, the below command can be used to migrate a guest from HostA to HostB.

# virsh --connect xen+ssh://HostA migrate --live xen+ssh://HostB

Replace HostA and HostB with its ip addresses or FQDNs. You would be asked for the root password of HostA first, then the HostB. Upon entering the right password for both hosts, migration would happen successfully.

3 - If you are currently logged into HostB and want to migrate a guest from HostA to HostB, can this be done using virsh? Try it out yourself.

Libvirt connection over ssh (xen+ssh) is the the method used in the above example. Libvirt remote TLS connection can also be established using certificates. Since that needs a bit more deails to setup, that is apt for another doc.