Share a Ceph cluster with an attached MKE cluster¶

TechPreview Available for non-MOSK clusters since 2.22.0

Caution

For MOSK-based deployments, the feature is not supported yet.

A shared Ceph cluster supports Mirantis Kubernetes Engine (MKE) clusters that were not originally deployed by Container Cloud and are attached to the management cluster. Shared Ceph clusters allow providing the Ceph-based CSI driver to MKE clusters. Both ReadWriteOnce (RWO) and ReadWriteMany (RWX) access modes are supported with shared Ceph clusters.

Caution

Place the attached MKE clusters in the same region with the managed cluster that contains the Ceph cluster.

To connect a Ceph cluster to an attached MKE cluster:

Attach the current MKE cluster to the management cluster. See Attach an existing Mirantis Kubernetes Engine cluster for details.
Open the Cluster object for editing:
```
kubectl -n <attachedMKEclusterProjectName > edit cluster
```
Substitute <attachedMKEclusterProjectName > with the project name of the MKE cluster attached to the management cluster.

Add ceph-controller to the helmReleases section:

spec:
  providerSpec:
    helmReleases:
    ...
    - name: ceph-controller
      enabled: true
      values: {}

Wait for a corresponding Ceph controller Helm release deployment to complete:

kubectl -n <attachedMKEclusterProjectName > get helmbundle -o jsonpath='{range .items[*]}{@.status.releaseStatuses.ceph-controller}{"\n"}{end}'

Substitute <attachedMKEclusterProjectName > with the project name of the MKE cluster attached to the management cluster.

Example of a positive system response:

{"chart":"ceph-operator","finishedAt":"2022-11-16T14:37:38Z",
 "hash":"6cfb6e40b1f00f5b0bf86256504a33b4e8415093b28a1edd19c5e0cf82892609",
 "helmV3":false,"message":"Install complete","namespace":"ceph","notes":"",
 "ready":true,"revision":1,"status":"deployed","success":true,
 "version":"1.0.0-mcc-2.22-3"}

Connect the Ceph cluster to the attached MKE cluster. See Connect to and manage a shared Ceph cluster for details.

Note

Admission Controller allows creating KaaSCephCluster for MKE attached clusters only for sharing purposes.
Enable the Ceph pools and CephFS data pools on the shared Ceph cluster. See Consume pools from the Ceph cluster for details.

After connecting the Ceph cluster to the MKE cluster and specifying Ceph pools and CephFS, Ceph Controller creates corresponding StorageClass objects that you can use for creating RWO and RWX persistent volumes in the MKE cluster.