Comment 6 for bug 2007859

I was able to reproduce this issue in my lab by luck and my workaround is following:

1) For example, if the message is "Waiting on juju-4c2163-3-lxd-3 to finish upgrading", then reboot that particular lxd or ceph-mon/<node-number>

# in my case, this particular node is not a leader, but it is a leader before upgrade
$ juju ssh ceph-mon/<node-number>
$ reboot

2) After the reboot, the juju status will show failure on that node, but I found it had recovered by itself in juju logs, hence resolve the ceph-mon node

$ juju resolve ceph-mon/<node-number>

Then all ceph-mon nodes are ready and clustered.