On Monday, December 29, 2025 10:22:13 AM Eastern Standard Time Iztok Gregori via ceph-users wrote:

On 29/12/25 14:57, Anthony D'Atri wrote:

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In my case it will be used to "adopt" the services, but after that what is its intended usage? The "orchestrator" should be used to add/remove new hosts and to upgrade the cluster.

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Cephadm *is* the orchestrator. The nomenclature may seem misleading. There’s part that runs on each node as well as a Manager module, and CLI commands.

Understand. My question was around the "cephadm" command, the one documentation says that has to be installed on all the nodes to start the "adoption" process. I'm not sure if this command is needed only for that process or is an integral part of the cephadm/orchestrator.

The cephadm system is split into two parts - a manager module and the cephadm command. The command is often called "the binary" or a little more verbosely "the cephadm binary". A system may often have two or more copies of the cephadm binary on a node. There's the copy that is installed by an administrator (typically) that is run for bootstrapping or adoption and for some administrative commands. Then there's a copy that is pushed to nodes from the mgr module. This copy of the binary is coupled to the mgr module (you can find cached copies under /var/lib/ ceph). I hope this short architectural description is helpful. :-)

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I'm asking this question because my upgrade path consists in multiple consecutive upgrades and I see that for the latest version of Quincy (17.2.9) and for newer Ceph releases there is no cephadm "package" for el8

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Check the compatibility matrix in the docs.

Mhmm... I suspect that I'm entering in some edge case here (end exiting the subject of this thread). I have a cluster running Ceph Octopus 15.2.17 on EL8 (almost all the nodes, some nodes are EL7 but can be reinstalled/removed). My goal is to upgrade it AND to embrace cephadm as orchestrator. My plan is/was:

1. Adopt cephadm (with octopus containers) 2. Upgrade to Quincy. 3. Upgrade to Squid.

But now looking to the various compatibility matrices I'm start to worry that this is not possible:

- Podman on EL8 is version 4, but from the table https://docs.ceph.com/en/squid/cephadm/compatibility/#cephadm-compatibility-> with-podman

podman will not run with Octopus.

- There is no mention of EL8 in https://docs.ceph.com/en/squid/start/os-recommendations/

I could skip the adoption with Octopus containers and go directly with adoption+upgrade to Quincy. But I'll end up with in any case with most hosts running EL8 which I cannot find in any matrices.

So the best solution will be to upgrade all the machines to EL9 and concurrently upgrade Ceph to Quincy. For the MON and MGR shouldn't be too much of a problem (it should be possible to add a new monitor with newer ceph release to an existing cluster), but how to reinstall the OSD servers without data movement?

In theory it should suffice to put the cluster in 'noout', reinstall the host without touching the OSD disks and then recreate the OSDs. Is this possible?

Thank you for your time! Iztok

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