Comment 2 for bug 1860743

Running those actions resulted in:

2020-02-06 23:33:41 DEBUG clear-unit-knownhost-cache # 10.35.101.62:22 SSH-2.0-OpenSSH_7.6p1 Ubuntu-4ubuntu0.3
  2020-02-06 23:33:41 DEBUG worker.uniter.jujuc server.go:182 running hook tool "juju-log"
  2020-02-06 23:33:41 INFO juju-log Adding SSH host key to known hosts for compute node at 10.35.101.62.
 (etc etc)

i.e. the incorrect (oam network) address, not the address listed in libvirt-migration-network

The action itself also failed with "DEBUG clear-unit-knownhost-cache ERROR key "Units updated" must start and end with lowercase alphanumeric, and contain only lowercase alphanumeric, hyphens and periods".

I tried manually accepting the host keys, by ssh'ing as nova and root from each compute host, to every other compute host using the 10.35.102.0/24 address. That did allow live-migration to complete, but as a workaround it's a very painful process.

I also note https://bugs.launchpad.net/charm-nova-compute/+bug/1823309 - in our case, the hosts all resolve to the address on 10.35.101.0/24 which is the one we don't want to use for livemigration.