Rook — Cloud-Native Storage Orchestrator for Kubernetes

What it is

Rook is a CNCF-graduated storage orchestrator for Kubernetes. It deploys and manages Ceph -- a distributed storage system -- as native Kubernetes resources. Through a Kubernetes operator and custom resource definitions (CRDs), Rook handles provisioning, scaling, healing, and upgrading of storage clusters.

Rook targets platform teams that need persistent storage in Kubernetes without managing Ceph infrastructure manually. It provides block storage (RBD), shared filesystems (CephFS), and S3-compatible object storage (RGW).

How it saves time or tokens

Managing Ceph manually requires deep expertise in distributed storage, monitor quorums, OSD placement, and failure recovery. Rook encodes this expertise in a Kubernetes operator that handles the operational complexity. A CephCluster custom resource replaces pages of manual configuration.

Rook also handles automatic recovery: when an OSD fails, the operator detects it and rebuilds the data on healthy nodes.

How to use

1. Deploy the Rook operator:

git clone --single-branch --branch release-1.14 https://github.com/rook/rook.git
cd rook/deploy/examples
kubectl create -f crds.yaml -f common.yaml -f operator.yaml

1. Create a Ceph cluster:

# cluster.yaml
apiVersion: ceph.rook.io/v1
kind: CephCluster
metadata:
  name: rook-ceph
  namespace: rook-ceph
spec:
  dataDirHostPath: /var/lib/rook
  mon:
    count: 3
  storage:
    useAllNodes: true
    useAllDevices: true

kubectl create -f cluster.yaml

1. Create a StorageClass for dynamic provisioning:

kubectl create -f csi/rbd/storageclass.yaml

Example

# PersistentVolumeClaim using Rook-managed Ceph
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: app-data
spec:
  accessModes: [ReadWriteOnce]
  storageClassName: rook-ceph-block
  resources:
    requests:
      storage: 10Gi
---
# Pod using the PVC
apiVersion: v1
kind: Pod
metadata:
  name: app
spec:
  containers:
  - name: app
    image: myapp:latest
    volumeMounts:
    - name: data
      mountPath: /data
  volumes:
  - name: data
    persistentVolumeClaim:
      claimName: app-data

Related on TokRepo

• AI Tools for DevOps -- Kubernetes and infrastructure management tools
• AI Tools for Self-Hosted -- Self-hosted infrastructure components

Common pitfalls

• Rook requires raw block devices or empty partitions on Kubernetes nodes. Using devices that already have filesystems causes deployment failures.
• Minimum 3 nodes with storage devices for a production Ceph cluster. Single-node deployments work for testing but have no redundancy.
• Ceph is resource-intensive. Each OSD daemon needs 2-4GB RAM. Plan node resources accordingly.