When I shutdown Openstack compute host (for example reboot required by updates) what happens to virtual machines that were running on that host?
I know that when host starts again the virtual machines are in shutdown state. But were they shutdown normally or was it like the power cord was pulled off?
I am wondering if it necessary to shutdown all virtual machines before shutting down the host server. Virtual machines in question don't need any special operations before shutdown.
Openstack versions I am interested in are Icehouse and Juno. Hypervisor used is KVM.
Best Answer
This is more about libvirt than OpenStack itself. When the libvirt daemon is shutting down during host shutdown, it tries to gracefully shut down all of the guests. If any don't shut down within a grace period, they get unceremonially killed. So in answer to your question, it depends whether your guests shut down in a reasonable timeframe or not.