Red Hat Bugzilla – Bug 974888
Why virtual guest is migrated when the virtual host move to maintenance mode ?
Last modified: 2015-09-22 09:09 EDT
From my understanding, virtual machines have to migrate from a host in maintenance mode, even though you've selected "do not migrate" as your policy.
The alternative is just having running virtual machines die, or not being able to put into maintenance mode any hosts in a cluster with "do not migrate" policy set. When a host unexpectedly shuts down, virtual machines are again on another host depending on your policy.
"Do not migrate" means that virtual machine will not migrate in case of excessive load on a specific host.
For a virtual machine to not migrate at all, you want to pin it to a host CPU. That means it needs a specific CPU and will not start on a different host if the host it is pinned to dies unexpectedly.
Check out "CPU Pinning Topology" in this section: