Red Hat OpenShift Data Foundation—previously Red Hat OpenShift Container Storage—is software-defined storage for containers.
The previous two tutorials in this series explained how to deploy Red Hat OpenShift Data Foundation on IBM Power Systems and to validate it. This tutorial shows how to use Ceph’s block and file storage in your application workload pods.
To use Ceph’s block and file storage in your application workload pods, you need a functioning and validated OpenShift Container Platform and OpenShift Data Foundation.
It takes around 1 hour to complete the steps outlined in this tutorial to use Ceph block and file storage in your application workload pods.
To use Ceph’s block or file storage, you need to know the corresponding storage classes. These storage classes are pre-created for your convenience during the OpenShift Data Foundation deployment step.
|Storage class name||Provisioner|
Perform the following steps to use Ceph’s block and file storage in your application workload pods:
- Using these storage classes, create persistent volume claims (PVCs). But for convenience let us refer to something that is already done and available.
While going through the Verify Red Hat OpenShift Data Foundation deployment on IBM Power Systems tutorial in this series, you would have cloned the rook example repository using the following command:
git clone https://github.com/rook/rook.git
In the cloned repository, find the mysql.yaml file in the rook/cluster/examples/Kubernetes directory. The mysql.yaml filehas the definitions for a PVC and deployment. There will be no reference to namespaces in this YAML file. So, create them in your current namespace. In this file, you need to update the storage class name for the PVC definition.
Change the storage class name as:
Update the deployment image as:
Install the mysql workload pod:
# oc create -f rook/cluster/examples/kubernetes/mysql.yaml service/wordpress-mysql created persistentvolumeclaim/mysql-pv-claim created deployment.apps/wordpress-mysql created
After a few minutes, run the following commands and notice that both PVC and the pods are up and running:
# oc get pvc NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE mysql-pv-claim Bound pvc-2b454afe-d12c-42e7-b8da-4e91eb6384a5 20Gi RWO ocs-storagecluster-ceph-rbd 82s
In the output, notice that the
Boundindicating that the PVC is bound to the underlying persistent volume successfully.
# oc get pod NAME READY STATUS RESTARTS AGE wordpress-mysql-77c9dffd88-b4rcm 1/1 Running 0 85s
According to the definition of deployment in mysql.yaml, the Ceph block volume is mounted under the /var/lib/mysql directory. verify the same using the following commands:
# oc rsh wordpress-mysql-77c9dffd88-b4rcm sh sh-4.4$ cd /var/lib/mysql sh-4.4$ ls -la total 32 drwxrwxrwx. 4 root root 4096 May 22 23:09 . drwxr-xr-x. 1 root root 108 May 5 16:57 .. drwxr-x---. 6 mysql mysql 4096 May 22 23:09 data drwx------. 2 root root 16384 May 22 23:08 lost+found srwxrwxrwx. 1 mysql mysql 0 May 22 23:09 mysql.sock -rw-------. 1 mysql mysql 2 May 22 23:09 mysql.sock.lock srwxrwxrwx. 1 mysql mysql 0 May 22 23:09 mysqlx.sock -rw-------. 1 mysql mysql 3 May 22 23:09 mysqlx.sock.lock sh-4.4$ exit exit
mysqland the corresponding persistent volume are created and are available.
# oc get pv | grep mysql pvc-2b454afe-d12c-42e7-b8da-4e91eb6384a5 20Gi RWO Delete Bound default/mysql-pv-claim ocs-storagecluster-ceph-rbd 5m47s
This demonstrates that a persistent volume claim is carved out of Ceph’s block storage, and it is allocated and mounted successfully in a pod.
After deploying OpenShift Data Foundation on OpenShift Container Platform on IBM Power Systems, you can follow the steps in this tutorial to use Ceph’s block and file storage in your application workload pods.
Refer to the following tutorials for more information: