Which Ceph release are you running, and how was it deployed? With some older releases I experienced mons behaving unexpectedly when one of the quorum bounced, so I like to segregate them for isolation still.
There was also at point an issue where clients wouldn’t get a runtime update of new mons. I endorse Eugen’s strategy, but must ask first the server and client releases involved. Especially since you wrote “old”. > On Sep 9, 2023, at 5:28 AM, Eugen Block <[email protected]> wrote: > > Hi, > > is it an actual requirement to redeploy MONs? Because almost all clusters we > support or assist with have MONs and OSDs colocated. MON daemons are quite > light-weight services, so if it's not really necessary, I'd leave it as it is. > If you really need to move the MONs to different servers, I'd recommend to > add the new MONs one by one. Your monmap will then contain old and new MONs, > and when all new MONs (with new IPs) are up and running you can remove the > old MON daemons. There's no need to switch off OSDs or drain a host. You can > find more information in the Nautilus docs [1] where the orchestrator wasn't > available yet. > > Regards, > Eugen > > [1] https://docs.ceph.com/en/nautilus/rados/operations/add-or-rm-mons/ > > Zitat von Ramin Najjarbashi <[email protected]>: > >> Hi >> >> I >> am writing to seek guidance and best practices for a maintenance operation >> in my Ceph cluster. I have an older cluster in which the Monitors (Mons) >> and Object Storage Devices (OSDs) are currently deployed on the same host. >> I am interested in separating them while ensuring zero downtime and >> minimizing risks to the cluster's stability. >> >> The primary goal is to deploy new Monitors on different servers without >> causing service interruptions or disruptions to data availability. >> >> The challenge arises because updating the configuration to add new Monitors >> typically requires a restart of all OSDs, which is less than ideal in terms >> of maintaining cluster availability. >> >> One approach I considered is to reweight all OSDs on the host to zero, >> allowing data to gradually transfer to other OSDs. Once all data has been >> safely migrated, I would proceed to remove the old OSDs. Afterward, I would >> deploy the new Monitors on a different server with the previous IP >> addresses and deploy the OSDs on the old Monitors' host with new IP >> addresses. >> >> While this approach seems to minimize risks, it can be time-consuming and >> may not be the most efficient way to achieve the desired separation. >> >> I would greatly appreciate the community's insights and suggestions on the >> best approach to achieve this separation of Mons and OSDs with zero >> downtime and minimal risk. If there are alternative methods or best >> practices that can be recommended, please share your expertise. >> _______________________________________________ >> ceph-users mailing list -- [email protected] >> To unsubscribe send an email to [email protected] > > > _______________________________________________ > ceph-users mailing list -- [email protected] > To unsubscribe send an email to [email protected] _______________________________________________ ceph-users mailing list -- [email protected] To unsubscribe send an email to [email protected]
