Comment 8 for bug 1624997

James,

I just filed a related bug which narrows down that this is happening if ceph-osd configures ssh key exchanges before nova-compute unit is added to the host.

https://bugs.launchpad.net/charm-nova-compute/+bug/1677707

This is also a Xenial Mitaka cloud, these nodes were added to a juju-deployer environment (Bootstack) manually by adding ubuntu charm to provision host, then ceph-osd add-unit, then nova-compute add-unit.