Exactly. Use the orchestrator, Luke. Additionally I would set count:3 for the mgr service. It’s kind of a hassle to recover from no active mgr so I encourage running one alongside every mon.

On Jul 21, 2026, at 4:30 PM, Eugen Block via ceph-users <ceph-users@ceph.io> wrote:

Hi,

Ceph is highly-available by design. So if you have three MON nodes (and two MGR services deployed along them) you're good as long as you have quorum and an admin keyring on more than one node. With cephadm you can manage the presence of the admin keyring via orchestrator and the _admin label [0]. That enables you to manage the cluster from any admin node. Not sure what you mean by "bootstrap file" though...

If you'd synced the /var/lib/ceph directory, you'd overwrite all the daemons but one, including keyring etc. So please don't do that, that would break your cluster.

Regards, Eugen

[0] https://docs.ceph.com/en/latest/cephadm/operations/#enabling-management-of-a...

Zitat von Michel Le Cocq via ceph-users <ceph-users@ceph.io>:

...

Hi all,

I am currently deploying a Ceph cluster with cephadm on 3 nodes with MON, MGR, and MDS roles. OSDs will be added later.

My goal is for these 3 nodes to be fully interchangeable, with the ability to administer the cluster from any of them without risk if a node fails.

I have identified that the solution involves synchronizing /var/lib/ceph/ (excluding the bootstrap file) across all nodes.

However:

- Is this the right approach to achieve this goal?

- Which tool should I use for reliable bidirectional synchronization?

- What are the potential risks (conflicts, corruption) and precautions to take?

Have you implemented such a configuration in production before?

Thank you for your advice.

-- Michel _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-leave@ceph.io

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