[kolla] Updating libvirt container images without VM downtime

Hi,

I'm looking for validation regarding the way Kolla and containers work in regard to upgrading the libvirt containers. Essentially, when you upgrade the libvirt container to a new container image, the container needs to be restarted, thus creating downtime for the VMs. There is no way to avoid this downtime, unless you migrate the VMs to another node and then move them back once the container has restarted, right?