I think I found the problem. Setting the cephadm log level to debug and then watching the logs during the upgrade: ceph config set mgr mgr/cephadm/log_to_cluster_level debug ceph -W cephadm --watch-debug I found this line just before the error: ceph: stderr Fatal glibc error: CPU does not support x86-64-v2 The same error comes out if I try to launch the container manually on the culprit machine, so I'd say it's a dead end. What I don't understand is how such a big change like dismissing support for an old architecture has been introduced in a point release (18.2.2 works fine), but maybe it's just me that's missing some basic info about the versioning scheme of Ceph. Anyway, now I'm stuck with 3 daemons running 18.2.4 and the others still on 18.2.2. The cluster looks happy and I see no malfunctioning, can I leave it in this state with no risk? If not, is it safe to rollback the 3 upgraded daemons to the previous version? Thanks again, Nicola