https://backend-engineering-strategy-tools.github.io/site/tags/storage-class/Recent content in Storage-Class on Backend Engineering Strategy ToolsHugo -- gohugo.ioen-usThu, 14 May 2026 00:00:00 +0000https://backend-engineering-strategy-tools.github.io/site/public-notes/kubernetes/rook/Thu, 14 May 2026 00:00:00 +0000https://backend-engineering-strategy-tools.github.io/site/public-notes/kubernetes/rook/<p>Rook is a Kubernetes operator that deploys and manages storage systems — primarily <a class="link" href="https://backend-engineering-strategy-tools.github.io/site/public-notes/cloud-infrastructure/ceph/" >Ceph</a> — as native Kubernetes resources. The distinction: Ceph is the storage system; Rook is the Kubernetes wiring around it.</p> <p>Without Rook you would run Ceph manually (or via <code>cephadm</code>) and then configure the Kubernetes CSI driver separately. Rook collapses that into CRDs and handles the full lifecycle: deployment, configuration, expansion, upgrades, and failure recovery.</p> <hr> <h2 id="how-it-works">How it works </h2><p>Rook introduces several CRDs:</p> <p><strong>CephCluster</strong> — declares the cluster: which nodes, which disks to use as OSDs, replication settings.</p> <p><strong>CephBlockPool</strong> — defines a Ceph pool (replication factor, failure domain). Maps to an RBD pool.</p> <p><strong>StorageClass</strong> — references a CephBlockPool and enables dynamic PVC provisioning. Kubernetes workloads request storage; Rook/Ceph fulfils it.</p> <p><strong>CephFilesystem</strong> — deploys CephFS + MDS for POSIX shared filesystem access.</p> <p><strong>CephObjectStore</strong> — deploys the Ceph RGW S3-compatible object storage gateway.</p> <hr> <h2 id="typical-install-sequence">Typical install sequence </h2><div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;-webkit-text-size-adjust:none;"><code class="language-sh" data-lang="sh"><span style="display:flex;"><span>kubectl apply -f https://raw.githubusercontent.com/rook/rook/refs/tags/v1.17.9/deploy/examples/crds.yaml </span></span><span style="display:flex;"><span>kubectl apply -f https://raw.githubusercontent.com/rook/rook/refs/tags/v1.17.9/deploy/examples/common.yaml </span></span><span style="display:flex;"><span>kubectl apply -f https://raw.githubusercontent.com/rook/rook/refs/tags/v1.17.9/deploy/examples/operator.yaml </span></span></code></pre></div><p>Then apply a <code>CephCluster</code> manifest declaring your storage topology, followed by <code>CephBlockPool</code> and <code>StorageClass</code> for PVC support.</p> <hr> <h2 id="single-node-considerations">Single-node considerations </h2><p>A single-node setup requires <code>allowMultiplePerNode: true</code> in the <code>CephCluster</code> spec (MONs, MGR, and OSDs all land on the same node). Replication <code>size</code> must be set to <code>1</code> — there is nowhere else to replicate. This works for experimentation; it is not a production configuration. See <a class="link" href="https://backend-engineering-strategy-tools.github.io/site/public-notes/cloud-infrastructure/ceph/" >Ceph</a> for details on the replication model.</p> <hr> <h2 id="related">Related </h2><ul> <li><a class="link" href="https://rook.io/docs/rook/latest/" target="_blank" rel="noopener" >Rook documentation</a></li> <li><a class="link" href="https://backend-engineering-strategy-tools.github.io/site/public-notes/cloud-infrastructure/ceph/" >Ceph</a> — the underlying storage system</li> <li><a class="link" href="https://backend-engineering-strategy-tools.github.io/site/homelab/rook-ceph/" >Rook + Ceph in the homelab</a></li> </ul>