lxd vms using OVN networks get different IPs on mass reboot

[Nishant Dash]

This is an extension of
- https://github.com/canonical/lxd/issues/11658

I have a scenario where I am using juju deployed on LXD vms in a microcloud setup and rebooting a single vm mutliple times does not result in an ip change but rebooting a physical host results in almost every vm on that host getting a new ip, even with volatile.eth0.last_state.ip_addresses being set.

Versions:

    lxd: 5.21.1-10f4115
    microovn: 22.03.3+snap0e23a0e4f5
    microceph: 0+git.4a608fc
    microcloud: 1.1-04a1c49

Other related:
- https://bugs.launchpad.net/juju/+bug/2007595

[Peter Jose De Sousa (pjds)]

subscribing field high as a workaround exists.

[Nishant Dash (dash3)]

Subscribed field high since we can workaround with lxd device overrides (in terraform as well).

[Martin Kalcok (martin-kalcok)]

As discussed further in the github issue[0], this behavior occurs due to the way LXD handles starting and stopping of guest instances (note that this does not affect rebooting guests, just stopping/starting via LXC cli). When the guest is stopped, LXD removes its ports from the OVN via Northbound API, therefore addresses previously assigned to these ports become freely available, and can be assigned to other guests. If new guest instances are brought up while existing instances are stopped, it can lead IP re-shuffle.

From the point of view of OVN/MicroOVN, everything works as expected.

[0] https://github.com/canonical/lxd/issues/11658