Hey Wodel, Converting an existing Ceph cluster from ceph-ansible to cephadm is a feasible process, and it can be done without causing downtime or interruptions. Here are the steps from my side, you can follow: Preparation Step: Ensure that the cephadm command line tool is available on each host in the existing cluster. Choose a version of Ceph for the conversion. This procedure works with any release of Ceph from Octopus (15.2.z) onwards. Pass the desired Ceph image to cephadm using the following command: cephadm --image $IMAGE <rest of command goes here> Confirm that the conversion has started by running: cephadm ls Before starting the conversion, all existing daemons should have a style of “legacy” when you run cephadm ls. Adoption Process: Ensure that the Ceph configuration has been migrated to use the cluster config database. If the /etc/ceph/ceph.conf file is identical on each host, you can run the following command on one host to affect all hosts: ceph config assimilate-conf -i /etc/ceph/ceph.conf If there are configuration variations between hosts, repeat this command on each host. Adopt each monitor (MON) using the following command: cephadm adopt --style legacy --name mon.<hostname> Each legacy monitor will stop, quickly restart as a cephadm container, and rejoin the quorum. Adopt each manager (MGR) similarly: cephadm adopt --style legacy --name mgr.<hostname> Enable cephadm: ceph mgr module enable cephadm ceph orch set backend cephadm Generate an SSH key: ceph cephadm generate-key ceph cephadm get-pub-key > ~/ceph.pub Install the cluster SSH key on each host: ssh-copy-id -f -i ~/ceph.pub root@<host> You can also import an existing SSH key if needed. Upgrade to Ceph Q: If you plan to upgrade Ceph anyway and you stop your OpenStack platform, you can upgrade the cluster during adoption. For example, upgrading or converting an Octopus MON daemon would look like this: $ cephadm --image quay.io/ceph/ceph:v17.2.7 adopt --style legacy --name mon.ceph01 Best, Kerem ÇELİKER Head of Cloud Architecture linkedin.com/in/keremceliker/