Offline migrating KVM guests using virsh?

Question

I want to offline migrate the KVM guest e-devel to another centos73 host using virsh. So I do

# virsh -d 0 migrate --offline --persistent e-devel qemu+ssh://kvm2/system
migrate: offline(bool): (none)
migrate: persistent(bool): (none)
migrate: domain(optdata): e-devel
migrate: desturi(optdata): qemu+ssh://kvm2/system
migrate: found option <domain>: e-devel
migrate: <domain> trying as domain NAME
root@kvm2's password: 
migrate: found option <domain>: e-devel
migrate: <domain> trying as domain NAME

# 

After typing the root passowrd I would have expected the guest to be migrated, but nothing happens.

The last debug line migrate: <domain> trying as domain NAME seams to me that something is missing.

What does this line mean?

Solution 1

The message <domain> trying as domain NAME just means that the code is trying to lookup the guest based on its name (as opposed to UUID or ID). IOW, it is normal to see that here, no sign of problem.

The offline migrate facility doesn't really do anything much. It merely results in the XML config for the guest being copied to the target host, nothing more. In particular it will never copy any storage across to the target host.

IOW, the offline migrate is nothing you can't already do by running

  virsh dumpxml FOO > foo.xml
  scp foo.xml <targethost>
  virsh define foo.xml

Solution 2

virsh migrate offline expects storage to be in shared mode.

--offline migration does not have any option to copy the disk.

--copy-storage-all indicates migration with non-shared storage with full disk copy, but that works only with live migration.