Will `sudo reboot` on KVM host gracefully poweroff guest VMs?

Question

Currently I manually poweroff each KVM guest before rebooting the host. However, this is getting old and now I am up to about 20 guest machines.

Can I trust Ubuntu Server 12.04 to do the Right Thing and hold off on completing a shutdown until the last KVM client is off?

Alternatively is there an easier way to shut all the guests off gracefully?

Solution

Yes, this is done automatically, according to this fixed bug: https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/350936

See also: https://serverfault.com/questions/200751/can-kvm-suspend-or-shutdown-guests-automatically-on-host-shutdown

Comments

[Admin]

Something to think about: a shutdown script that would send some sort of "shutdown all VMs" signal to KVM. The idea needs some fleshing out, but if KVM supports command-line control, it wouldn't be too hard to create a simple shutdown script to do that.

[Admin]

Yes - this could be done via the virsh command, I'm looking for something more out-of-the-box. According to this launchpad bug, it may already Just Work: bugs.launchpad.net/ubuntu/+source/kvm/+bug/350936

[Admin]

On RedHat they have a script called libvirt-guests which takes care of this automatically, but for whatever reason, Ubuntu doesn't include this script in their package. launchpad.net/ubuntu/+source/libvirt/0.9.8-2ubuntu1

[Admin]

ok - looking /etc/init/libvirt-bin it appears that the necessary code is in there to do this. I just completed a test run and it did work, but I needed to increase the timeout that was in that file from 30 seconds to 2 minutes.

[Admin]

As a system admin I'm shocked to see the timeout in /etc/init/libvirt-bin.conf is ONLY 30 seconds. Checking the code I see this isn't even per VM, it is total. I've seen a physical (non-VM) production server that take 15min to shutdown on new fast hardware after a fresh install and databases restored. My Work's current main VM server takes nearly 10mins to shutdown due to the 30VMs with multiple databases etc.

[Admin]

I just learned you are supposed to put changes into a new /etc/init/libvirt-bin.override file instead of changing the .conf file. According to upstart.ubuntu.com/cookbook/#override-files and sebastian.marsching.com/wiki/Linux/KVM

[James Hancock]

Ubuntu 19.04 does not actually do this.