Attempting to add persistent block storage to the ODEN single-node Talos cluster using Rook and Ceph. This did not fully succeed — the setup reached the point of a bound PVC and a working write test, but the cluster was not left in a clean stable state. Notes are here for completeness.

This builds on the Talos cluster setup on ODEN.

Hardware

ODEN has five storage devices:

Do not add /dev/sdb to Ceph. It is the boot disk.

Step 1 — Install the Rook operator

kubectl apply -f https://raw.githubusercontent.com/rook/rook/refs/tags/v1.17.9/deploy/examples/crds.yaml
kubectl apply -f https://raw.githubusercontent.com/rook/rook/refs/tags/v1.17.9/deploy/examples/common.yaml
kubectl apply -f https://raw.githubusercontent.com/rook/rook/refs/tags/v1.17.9/deploy/examples/operator.yaml

Wait for the operator pod to be running in rook-ceph namespace before continuing.

Step 2 — CephCluster (single-node)

Single-node requires allowMultiplePerNode: true and explicit disk selection. The cluster-test example from the Rook repo is a reasonable starting point:

storage:
  useAllNodes: false
  nodes:
    - name: "192.168.1.171"
      devices:
        - name: "nvme0n1"
        - name: "sdc"
        - name: "sdd"
        - name: "sde"

Reference: cluster-test.yaml

Step 3 — CephBlockPool and StorageClass

apiVersion: ceph.rook.io/v1
kind: CephBlockPool
metadata:
  name: replicapool
  namespace: rook-ceph
spec:
  replicated:
    size: 1

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: rook-ceph-block
provisioner: rook-ceph.rbd.csi.ceph.com
parameters:
  clusterID: rook-ceph
  pool: replicapool
  imageFormat: "2"
  imageFeatures: layering
reclaimPolicy: Delete

Step 4 — PVC test

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: test-pvc
spec:
  accessModes:
    - ReadWriteOnce
  storageClassName: rook-ceph-block
  resources:
    requests:
      storage: 10Gi

PVC reached Bound. A BusyBox pod mounting it could write to /mnt. The Ceph dashboard (kubectl -n rook-ceph port-forward svc/rook-ceph-mgr-dashboard 7000:7000) showed OSDs active and the pool present.

What did not work

The cluster ran but was not left stable. Single-node Ceph produces health warnings by design (no redundancy, no failure domain separation). More importantly, the setup was not revisited after initial testing and there are unresolved questions about:

• CSI driver behaviour on Talos (Talos has specific requirements for CSI socket paths)
• Whether the dashboard warnings were cosmetic or indicated real issues
• Long-term stability under actual workloads

This is left as a draft until there is time to run it properly — ideally on more than one node.