Migrate a Ceph Monitor before machine replacement

Available since MCC 2.25.0 (Cluster release 17.0.0)

This document describes how to migrate a Ceph Monitor to another machine on baremetal-based clusters before node replacement as described in Delete a cluster machine using web UI.

Warning

  • Remove the Ceph Monitor role before the machine removal.

  • Make sure that the Ceph cluster always has an odd number of Ceph Monitors.

The procedure of a Ceph Monitor migration assumes that you temporarily move the Ceph Manager/Monitor to a worker machine. After a node replacement, we recommend migrating the Ceph Manager/Monitor to the new manager machine.

To migrate a Ceph Monitor to another machine:

  1. Move the Ceph Manager/Monitor daemon from the affected machine to one of the worker machines as described in Move a Ceph Monitor daemon to another node.

  2. Delete the affected machine as described in Delete a cluster machine.

  3. Add a new manager machine without the Monitor and Manager role as described in Create a machine using CLI.

    Warning

    The addition of a new machine with the Monitor and Manager role breaks the odd number quorum of Ceph Monitors.

  4. Move the previously migrated Ceph Manager/Monitor daemon to the new manager machine as described in Move a Ceph Monitor daemon to another node.