app: nginx-glusterfs template: metadata: labels: app: nginx-glusterfs spec: volumes: - name: demo-glusterfs-storage persistentVolumeClaim: claimName: glusterfs-pvc containers: - name: nginx-glusterfs-container image: nginx ports: - containerPort: 80 name: "http-server" volumeMounts: - mountPath: "/usr/share/nginx/html" name: demo-glusterfs-storage To test the volume, follow the steps described in “Testing the volume” on page 122 by using  the  selector app=nginx-glusterfs  and creating a file on one pod and verifying its existence  on the other one. In this section we demonstrate how to create a Ceph RBD cluster and a Rook management  agent in IBM Cloud Private. Ceph is open source software designed to provide highly scalable object, block and file-based  storage under a unified system. Ceph storage clusters are designed to run on commodity hardware, using an algorithm called  CRUSH (Controlled Replication Under Scalable Hashing) to ensure data is evenly distributed  across the cluster and that all cluster nodes can retrieve data quickly without any centralized  bottlenecks. See  https://ceph.com/ceph-storage/  for more information. Rook is an open source orchestrator for distributed storage systems running in cloud native  environments. Rook turns distributed storage software into self-managing, self-scaling, and self-healing  storage services. It does this by automating deployment, bootstrapping, configuration,  provisioning, scaling, upgrading, migration, disaster recovery, monitoring, and resource  management. Rook uses the facilities that are provided by the underlying cloud-native  container management, scheduling and orchestration platform to perform its duties. Rook integrates deeply into cloud native environments leveraging extension points and  providing a seamless experience for scheduling, lifecycle management, resource  management, security, monitoring, and user experience. See  https://rook.io  for more information. Chapter 4. Managing persistence in IBM Cloud Private  131 What is Rook What is Ceph? 4.3.4 Configuring Ceph and Rook for IBM Cloud Private