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Ceph pools for Cinder multi-backend

Warning

This procedure is valid for MOSK clusters that use the MiraCeph custom resource (CR), which is available since MOSK 25.2 to replace the deprecated KaaSCephCluster. For the equivalent procedure with the KaaSCephCluster CR, refer to the following section:

Ceph pools for Cinder multi-backend

The MiraCeph object supports multiple Ceph pools with the volumes role to configure Cinder multiple backends.

To define Ceph pools for Cinder multiple backends:

1. In the MiraCeph CR, add the desired number of Ceph pools to the pools section with the volumes role:

   kubectl -n ceph-lcm-mirantis edit miraceph
   

   Example configuration:

   pools:
   - default: false
     deviceClass: hdd
     name: volumes
     replicated:
       size: 3
     role: volumes
   - default: false
     deviceClass: hdd
     name: volumes-backend-1
     replicated:
       size: 3
     role: volumes
   - default: false
     deviceClass: hdd
     name: volumes-backend-2
     replicated:
       size: 3
     role: volumes
   

2. Verify that Cinder backend pools are created and ready:

   kubectl -n ceph-lcm-mirantis get mchealth -o yaml
   

   Example output:

   status:
     fullClusterStatus:
       blockStorageStatus:
         poolsStatus:
           volumes-hdd:
             present: true
             status:
               observedGeneration: 1
               phase: Ready
           volumes-backend-1-hdd:
             present: true
             status:
               observedGeneration: 1
               phase: Ready
           volumes-backend-2-hdd:
             present: true
             status:
               observedGeneration: 1
               phase: Ready
   

3. Verify that the added Ceph pools are accessible from the Cinder service. For example:

   kubectl -n openstack exec -it cinder-volume-0 -- rbd ls -p volumes-backend-1-hdd -n client.cinder
   kubectl -n openstack exec -it cinder-volume-0 -- rbd ls -p volumes-backend-2-hdd -n client.cinder
   

After the Ceph pool becomes available, it is automatically specified as an additional Cinder backend and registered as a new volume type, which you can use to create Cinder volumes.