Hi Edward, I'm operating a fairly similar setup. I have done a similar migration to what you described on a 19.x cluster: Migrated all hosts from an old HPE generation to a newer one. I added one of the new hosts to the cluster, migrated a mon, mgr, mds, rgw and osds, propagated the new IPs to firewalls and clients and eventually removed the old host. I repeated that for the remaining hosts. Due to a lack of rack space I had to do this host by host. The VMs and cephfs mounts did not experience issues during the migration (both Debian and RHEL machines). ~ Phillip On Wed, 2026-07-08 at 13:58 +0000, Edward R Huyer via ceph-users wrote:

I have a fairly run-of-the-mill cephadm managed/containerized 20.2.1 cluster.  Not hyperconverged or anything like that.  It's currently exporting RBD to a Proxmox VE 8.4 cluster (QEMU virtualization), and CephFS to a couple RHEL 8.x servers via kernel mounts.

I need to migrate the whole thing, including the monitors, to new hardware.  My question is, can I rely on the QEMU processes and kernel mounts to correctly update their internal monitor maps as I add new monitors and remove old monitors, or will I suddenly reach a point where the consumers can't find the monitors they started up with and lose their minds?  (I know I'll also need to update the static configs.)

I'm pretty sure it should Just Work so long as I don't do something dumb and lose quorum, but there's a big difference between "should" and "actually does", and I haven't been able to find any writeups of people actually doing it, so I'm asking here.  Is this likely to work?  Is this known to not work for some reason (e.g., the kernel mounts or QEMU processes never actually update their mon maps after startup)?

TIA!

----- Edward Huyer Golisano College of Computing and Information Sciences Rochester Institute of Technology Golisano 70-2373 152 Lomb Memorial Drive Rochester, NY 14623 585-475-6651 erhvks@rit.edu<mailto:erhvks@rit.edu>

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