Hello I first saw this problem about 2 years ago on ceph cluster (upgraded from 14 ... to 18) https://tracker.ceph.com/issues/64213 I'm unable to load cephadm module because of "ImportError: PyO3 modules may only be initialized once per interpreter process" error I tried to remove restful and nfs modules but they are still in the mgr config : # ceph daemon mgr.ceph-pa2-2 config show | grep -i modules "mgr_disabled_modules": "", "mgr_initial_modules": "restful iostat nfs", "mgr_standby_modules": "false", and I can't modify this key. I think it's in the ceph global config set by a previous ceph version (nothing in ceph.conf) # ceph-conf -D | grep module mgr_disabled_modules = mgr_initial_modules = restful iostat nfs mgr_module_path = /usr/share/ceph/mgr mgr_standby_modules = true I managed to fix the problem on another ceph 18 cluster many days of struggle but can't fix it on this cluster. here are the loaded modules : # ceph mgr module ls | grep on balancer on (always on) crash on (always on) devicehealth on (always on) orchestrator on (always on) pg_autoscaler on (always on) progress on (always on) rbd_support on (always on) status on (always on) telemetry on (always on) volumes on (always on) cephadm on prometheus on I'm running ceph 18.2.8 on debian 12. the aim of making cephadm work is to switch from legacy to orch / cephadm and upgrade to 20. should I consider upgrading my legacy cluster to tentacle and after that switching to cephadm ? Thanks for your help... Regards Cédric