Hello,
I'm following this guide https://pve.proxmox.com/wiki/Ceph_Luminous_to_Nautilus to upgrade Ceph on my 6 nodes cluster.
Everything goes fine till "systemctl restart ceph-mgr.target", at this point the 3 managers don't restart.
Issuing "ceph -s" shows:
services:
...
mgr: no daemons...