# Guided Exercise: Provision Persistent Data Volumes Deploy a MySQL database with persistent storage from a PVC and identify the PV and storage provisioner that backs the application. **Outcomes** You should be able to do the following tasks: * Deploy a MySQL database with persistent storage from a PVC. * Identify the PV that backs the application. * Identify the storage provisioner that created the PV. As the `student` user on the `workstation` machine, use the `lab` command to prepare your system for this exercise. This command ensures that all resources are available for this exercise. ```plaintext [student@workstation ~]$ lab start storage-volumes ``` **Procedure 5.2. Instructions** 1. Log in to the OpenShift cluster as the `developer` user with the `developer` password. Use the `storage-volumes` project. 1. Log in to the OpenShift cluster. ```plaintext [student@workstation ~]$ oc login -u developer -p developer \ https://api.ocp4.example.com:6443 Login successful. ...output omitted... ``` 2. Set the `storage-volumes` project as the active project. ```plaintext [student@workstation ~]$ oc project storage-volumes ...output omitted... ``` 2. Identify the default storage class for the cluster. 1. Use the `oc get storageclass` command to identify the default storage class. ```plaintext [student@workstation ~]$ oc get storageclass NAME PROVISIONER ... nfs-storage (default) k8s-sigs.io/nfs-subdir-external-provisioner ... lvms-vg1 topolvm.io ... ``` 3. Use the [`registry.ocp4.example.com:8443/rhel8/mysql-80`](http://registry.ocp4.example.com:8443/rhel8/mysql-80) container image to create a MySQL deployment named `db-pod`. Add the missing environment variables for the pod to run. 1. Create the `db-pod` deployment. Ignore the warning message. ```plaintext [student@workstation ~]$ oc create deployment db-pod --port 3306 \ --image=registry.ocp4.example.com:8443/rhel8/mysql-80 ...output omitted... deployment.apps/db-pod created ``` 2. Add the environment variables. Ignore the warning message. ```plaintext [student@workstation ~]$ oc set env deployment/db-pod \ MYSQL_USER=user1 \ MYSQL_PASSWORD=mypa55w0rd \ MYSQL_DATABASE=items ...output omitted... deployment.apps/db-pod updated ``` 3. Confirm that the pod is running. ```plaintext [student@workstation ~]$ oc get pods NAME READY STATUS RESTARTS AGE db-pod-6ccc485cfc-vrc4r 1/1 Running 0 2m30s ``` 4. Expose the `db-pod` deployment to create a service. ```plaintext [student@workstation ~]$ oc expose deployment/db-pod service/db-pod exposed ``` 4. Use the `oc get deployment` command to view the pod template specification for the deployment. 1. Retrieve the pod template specification for the deployment. ```plaintext [student@workstation ~]$ oc get deployment/db-pod -o json | \ jq .spec.template.spec.containers [ { "env": [ { "name": "MYSQL_USER", "value": "user1" }, { "name": "MYSQL_PASSWORD", "value": "mypa55w0rd" }, { "name": "MYSQL_DATABASE", "value": "items" } ], "image": "registry.ocp4.example.com:8443/rhel8/mysql-80", "imagePullPolicy": "Always", "name": "mysql-80", "ports": [ { "containerPort": 3306, "protocol": "TCP" } ], "resources": {}, "terminationMessagePath": "/dev/termination-log", "terminationMessagePolicy": "File" } ] ``` 5. Add a 1 Gi, RWO PVC named `db-pod-pvc` to the deployment. Specify the volume name as `nfs-volume-storage`, and set the `/var/lib/mysql` directory as the mount path. 1. Use the `oc set volume` command to create a PVC for the deployment. Ignore the warning message. ```plaintext [student@workstation ~]$ oc set volumes deployment/db-pod \ --add --name nfs-volume-storage --type pvc \ --claim-mode rwo --claim-size 1Gi --mount-path /var/lib/mysql \ --claim-name db-pod-pvc ...output omitted... deployment.apps/db-pod volume updated ``` 2. Use the `oc get pvc` command to view the status of the PVC. Identify the name of the PV, and confirm that the PVC uses the `nfs-storage` default storage class. ```plaintext [student@workstation ~]$ oc get pvc NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS ... db-pod-pvc Bound pvc-13...ca45 1Gi RWO nfs-storage ... ``` 6. Observe how the `oc set volume` command changed the deployment. 1. Use the `oc get deployment` command to view the deployment again. ```plaintext [student@workstation ~]$ oc get deployment/db-pod -o yaml apiVersion: apps/v1 kind: Deployment ...output omitted... volumeMounts: - mountPath: /var/lib/mysql name: nfs-volume-storage ...output omitted... volumes: - name: nfs-volume-storage persistentVolumeClaim: claimName: db-pod-pvc ...output omitted... ``` 7. Use a `configMap` resource as a temporary volume to add initialization data to the database. 1. Observe the contents of the `init-db.sql` script that initializes the database. ```plaintext [student@workstation ~]$ cat \ ~/DO180/labs/storage-volumes/configmap/init-db.sql ``` ```plaintext DROP TABLE IF EXISTS `Item`; CREATE TABLE `Item` (`id` BIGINT not null auto_increment primary key, `description` VARCHAR(100), `done` BIT); INSERT INTO `Item` (`id`,`description`,`done`) VALUES (1,'Pick up newspaper', 0); INSERT INTO `Item` (`id`,`description`,`done`) VALUES (2,'Buy groceries', 1); ``` 2. Use the contents of the `init-db.sql` file to create a `configMap` API object named `init-db-cm`. ```plaintext [student@workstation ~]$ oc create configmap init-db-cm \ --from-file=/home/student/DO180/labs/storage-volumes/configmap/init-db.sql configmap/init-db-cm created ``` 3. Add the `init-db-cm` `configMap` resource as a volume named `init-db-volume` to the deployment. Specify the volume type as `configmap`, and set the `/tmp/init-db` directory as the mount path. Ignore the warning message. ```plaintext [student@workstation ~]$ oc set volumes deployment/db-pod \ --add --name init-db-volume \ --configmap-name init-db-cm --type configmap \ --mount-path /tmp/init-db ...output omitted... deployment.apps/db-pod volume updated ``` 4. Capture the name of the pod in a variable. ```plaintext [student@workstation ~]$ PODNAME=$(oc get pods \ -o jsonpath='{.items[0].metadata.name}') ``` 5. Start a remote shell session inside the container. ```plaintext [student@workstation ~]$ oc rsh $PODNAME sh-4.4$ ``` 6. Use the `mysql` client to execute the database script in the `/tmp/init-db` volume. ```plaintext sh-4.4$ mysql -uuser1 -pmypa55w0rd items