hi folks, if you are upgrading from luminous to octopus, or you plan to do so, please read on. in octopus, osd will crash if it processes an osdmap whose require_osd_release flag is still luminous. this only happens if a cluster upgrades very quickly from luminous to nautilus and to octopus. in this case, there are good chances that an octopus OSD will need to consume osdmaps which were created back in luminous. because we assumed that ceph did not ugprade across major releases, in octopus, OSD will panic at seeing osdmap from luminous. this is a known bug[0], and already fixed in master. and the next octopus release will include the fix to address this issue. as a workaround, you need to wait a while after running ceph osd require-osd-release nautilus and optionally inject lots of osdmaps into cluster to ensure that the old luminous osd maps are trimmed: for i in `seq 500`; do ceph osd blacklist add 192.168.0.1 ceph osd blacklist rm 192.168.0.1 done after the whole cluster are active+clean, then upgrade to octopus. happy upgrading! cheers, -- [0] https://tracker.ceph.com/issues/44759 -- Regards Kefu Chai