Red Hat OpenShift Developer II: Building and Deploying Cloud-native Applications

Instructions

The lab script deploys an ephemeral PostgreSQL database that uses a secret to externalize the user, password, and database parameters.

In this lab, you are asked to make the PostgreSQL database persistent. Then, deploy the expense-service application and connect it the PostgreSQL database.

Finally, you are asked to configure liveness and readiness probes for the expense-service application deployment.

1. Log in to Red Hat OpenShift.

   1. Log in to OpenShift as the developer user.

      [student@workstation ~]$ oc login -u developer -p developer \
      https://api.ocp4.example.com:6443
      Login successful.
      ...output omitted...

   2. Ensure that you use the deployments-review project.

      [student@workstation ~]$ oc project deployments-review
      Already on project "deployments-review" on server "https://api.ocp4.example.com:6443".

2. Create a PersistentVolumeClaim object called postgres-pvc that uses the nfs-storage storage class. Set the storage size to 1Gi and use the ReadWriteOnce access mode.

   1. Create the pvc.yaml file with the following contents:

      apiVersion: v1
      kind: PersistentVolumeClaim
      metadata:
        name: postgres-pvc
      spec:
        storageClassName: nfs-storage
        accessModes:
          - ReadWriteOnce
        resources:
          requests:
            storage: 1Gi

   2. Create the persistent volume claim.

      [student@workstation ~]$ oc create -f pvc.yaml
      persistentvolumeclaim/postgres-pvc created

   3. Verify that the persistent volume claim is bound and ready to be used.

      [student@workstation ~]$ oc describe pvc postgres-pvc
      Name:          postgres-pvc
      Namespace:     deployments-review
      StorageClass:  nfs-storage
      Status:        Bound
      ...output omitted...

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3. Provide a persistent volume for the current PostgreSQL deployment. Mount the postgres-pvc persistent volume claim in the /var/lib/pgsql/data path.

   1. Verify the current volumes in the PostgreSQL deployment.

      [student@workstation ~]$ oc get dc/postgresql -o yaml | \
      grep -C3 postgresql-data
              terminationMessagePolicy: File
              volumeMounts:
              - mountPath: /var/lib/pgsql/data
                name: postgresql-data
            dnsPolicy: ClusterFirst
            restartPolicy: Always
            schedulerName: default-scheduler
      --
            terminationGracePeriodSeconds: 30
            volumes:
            - emptyDir: {}
              name: postgresql-data
        test: false
        triggers:
        - imageChangeParams:

      Currently, the deployment configuration uses the ephemeral postgresql-data volume of type EmptyDir.

   2. Modify the postgresql-data volume to use the postgres-pvc persistent volume claim.

      [student@workstation ~]$ oc edit dc/postgresql
      ...output omitted...
            terminationGracePeriodSeconds: 30
            volumes:
            - persistentVolumeClaim:
                claimName: postgres-pvc
              name: postgresql-data
        test: false
        triggers:
      ...output omitted...

      Save and quit the editor session. Alternatively, you can achieve the same result by using the oc set command:

      [student@workstation ~]$ oc set volume dc/postgresql \
      --add --name=postgresql-data -t pvc --claim-name=postgres-pvc \
      --mount-path /var/lib/pgsql/data --overwrite
      deploymentconfig.apps.openshift.io/postgresql volume updated

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4. Deploy the expense-service application.

   Use the following information to deploy the application:

   Deployment name	expense-service
   Container image	registry.ocp4.example.com:8443/redhattraining/ocpdev-deployments-review:4.12
   Application URL	http://expense-service-deployments-review.apps.ocp4.example.com

   Use the Deployment object to deploy the application.

   Additionally, the application requires the following environment variables to start:

   QUARKUS_DATASOURCE_USERNAME	PostgreSQL connection user
   QUARKUS_DATASOURCE_PASSWORD	PostgreSQL connection password
   QUARKUS_DATASOURCE_JDBC_URL	JDBC URL in the jdbc:postgresql://postgresql:5432/DATABASE format

   Use the secret called postgresql to inject environment variables into the expense-service deployment.

   1. Deploy the expense-service application:

      [student@workstation ~]$ oc new-app --name=expense-service \
      --image=registry.ocp4.example.com:8443/redhattraining/ocpdev-deployments-review:4.12
      --> Found container image ...output omitted...

   2. Set the environment variables to use the postgresql secret values.

      [student@workstation ~]$ oc set env deploy/expense-service \
      --from=secret/postgresql
      ...output omitted...
      deployment.apps/expense-service updated

   3. Edit the deployment and modify the environment variable names to fit the application requirements.

      [student@workstation ~]$ oc edit deploy/expense-service
      ...output omitted...
      spec:
        containers:
        - env:
          - name: DATABASE_NAME
            valueFrom:
              secretKeyRef:
                key: database-name
                name: postgresql
          - name: QUARKUS_DATASOURCE_PASSWORD
            valueFrom:
              secretKeyRef:
                key: database-password
                name: postgresql
          - name: QUARKUS_DATASOURCE_USERNAME
            valueFrom:
              secretKeyRef:
                key: database-user
                name: postgresql
      ...output omitted...

      Save the changes and exit your editor to apply the changes.

   4. Use the DATABASE_NAME environment variable to construct the QUARKUS_DATASOURCE_JDBC_URL environment variable.

      [student@workstation ~]$ oc set env deploy/expense-service \
      QUARKUS_DATASOURCE_JDBC_URL='jdbc:postgresql://postgresql:5432/$(DATABASE_NAME)'
      deployment.apps/expense-service updated

   5. Verify the environment variable configuration.

      [student@workstation ~]$ oc describe deploy/expense-service | \
      grep -A4 Environment
      Environment:
        DATABASE_NAME:                <set to the key 'database-name' in secret 'postgresql'>      Optional: false
        QUARKUS_DATASOURCE_PASSWORD:  <set to the key 'database-password' in secret 'postgresql'>  Optional: false
        QUARKUS_DATASOURCE_USERNAME:  <set to the key 'database-user' in secret 'postgresql'>      Optional: false
        QUARKUS_DATASOURCE_JDBC_URL:  jdbc:postgresql://postgresql:5432/$(DATABASE_NAME)

   6. Expose the expense-service service.

      [student@workstation ~]$ oc expose svc expense-service
      route.route.openshift.io/expense-service exposed

   7. Test that the application responds to requests.

      [student@workstation ~]$ curl -s \
      expense-service-deployments-review.apps.ocp4.example.com/expenses | jq
      [
        {
          "id": 5,
          "amount": 15.00,
          "associateId": 1,
          "name": "Phone",
          "paymentMethod": "CASH",
          "uuid": "4ee81cc3-83ab-1ef2-523b-d67f87793255"
        },
      ...output omitted...

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5. Configure liveness and readiness probes for the application deployment. Use the /q/health/live endpoint for liveness probe, and the /q/health/ready endpoint for readiness probe.

   Both probes should succeed after one successful call, and fail after one unsuccessful call, they should also set the timeout to 1 second, use 5 seconds initial delay, and activate every 5 seconds.

   Finally, both probes should use the 8080 port.

   1. Configure the liveness probe.

      [student@workstation ~]$ oc set probe deploy/expense-service \
      --liveness --get-url=http://:8080/q/health/live --timeout-seconds=1 \
      --initial-delay-seconds=5 --success-threshold=1 --failure-threshold=1 \
      --period-seconds=5
      deployment.apps/expense-service probes updated

   2. Configure the readiness probe.

      [student@workstation ~]$ oc set probe deploy/expense-service \
      --readiness --get-url=http://:8080/q/health/ready --timeout-seconds=1 \
      --initial-delay-seconds=5 --success-threshold=1 --failure-threshold=1 \
      --period-seconds=5
      deployment.apps/expense-service probes updated

   3. Verify probes in the deployment.

      [student@workstation ~]$ oc describe deploy/expense-service | \
      grep "http-get"
      Liveness:    http-get http://:8080/q/health/live delay=5s timeout=1s period=5s #success=1 #failure=1
      Readiness:   http-get http://:8080/q/health/ready delay=5s timeout=1s period=5s #success=1 #failure=1

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