Removing MONs

MONs can be scaled down via removing existing ceph-mon units.

  1. First, you need to make sure the cluster is healthy. To check the cluster health, run:

    juju ssh ceph-mon/leader sudo ceph status
  2. Remove a containerised ceph-mon unit (assuming ceph-mon/4 is the target unit):

    juju remove-unit ceph-mon/4

    If this procedure results in an even number of ceph-mon units, you may remove another unit until an odd number of ceph-mon units is reached in the cluster. Note that typically, a healthy cluster requires at least three ceph-mon units.

  3. Ensure the cluster is still in healthy state after being scaled down:

    juju ssh ceph-mon/leader sudo ceph status