Red Hat OpenShift Development I: Introduction to Containers with Podman

Instructions

1. Log in to the cluster as the developer user, and ensure that you use the ocp-multipod project.

   1. Log in to the cluster 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 ocp-multipod project.

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

2. Create a Deployment resource for the Gitea application.

   1. Use the oc create deployment command to create the Gitea deployment.

      Configure the deployment port 3030 and use the registry.ocp4.example.com:8443/redhattraining/podman-gitea:latest container image.

      [student@workstation ~]$ oc create deployment gitea --port 3030 \
        --image=registry.ocp4.example.com:8443/redhattraining/podman-gitea:latest
      Warning: would violate PodSecurity "restricted:v1.24" ...
      ...output omitted...
      deployment.apps/gitea created

      Note

      You can ignore pod security warnings for exercises in this course. Red Hat OpenShift uses the Security Context Constraints controller to provide safe defaults for pod security.

   2. Verify the pod status.

      [student@workstation ~]$ oc get po
      NAME                     READY   STATUS    RESTARTS   AGE
      gitea-6d446c7b48-b89hz   1/1     Running   0          75s

      If the pod is in the ContainerCreating status, repeat the preceding command after a few seconds.

      The preceding command uses the po short name to refer to the pod resource. In the preceding command, the names po, pod, and pods are equivalent.

3. Create a Deployment resource for a PostgreSQL database called gitea-postgres. The Gitea application uses the database to store data.

   You can use the completed file in the ~/DO188/solutions/openshift-multipod directory.

   1. Use the oc create deployment command to create the gitea-postgres database.

      Configure the deployment port 5432 and use the registry.ocp4.example.com:8443/rhel9/postgresql-13:1 container image.

      Use the --dry-run=client and -o yaml options to generate a YAML file, and redirect the output to the postgres.yaml file.

      [student@workstation ~]$ oc create deployment gitea-postgres --port 5432 -o yaml \
        --image=registry.ocp4.example.com:8443/rhel9/postgresql-13:1 \
        --dry-run=client > postgres.yaml
      no output expected

      The preceding command uses output redirection (>) to create the postgres.yaml file.

   2. Open the postgres.yaml file in an editor, such as gedit, and add the following environment variables:

      ...file omitted...
            containers:
            - image: registry.ocp4.example.com:8443/rhel9/postgresql-13:1
              name: postgresql-13
              ports:
              - containerPort: 5432
              env:
              - name: POSTGRESQL_USER
                value: gitea
              - name: POSTGRESQL_PASSWORD
                value: gitea
              - name: POSTGRESQL_DATABASE
                value: gitea
      ...file omitted...

      To get more information about the env property, execute the oc explain deployment.spec.template.spec.containers.env command.

      Warning

      The YAML format is white-space sensitive. You must use correct indentation.

      In the preceding example, the env: object indentation is 8 spaces.

   3. Use the oc create command to create the deployment.

      [student@workstation ~]$ oc create -f postgres.yaml
      Warning: would violate PodSecurity "restricted:v1.24"...
      ...output omitted...
      deployment.apps/gitea-postgres created

      If you receive an error, compare your postgres.yaml file to the complete ~/DO188/solutions/openshift-multipod/postgres.yaml file.

   4. Verify the pod status.

      [student@workstation ~]$ oc get po
      NAME                              READY   STATUS    RESTARTS   AGE
      gitea-6d446c7b48-rf578            1/1     Running   0          6m18s
      gitea-postgres-86d47f494d-7rl5g   1/1     Running   0          18s

4. Configure networking for the database.

   1. Expose the PostgreSQL database on the gitea-postgres hostname.

      [student@workstation ~]$ oc expose deployment gitea-postgres
      service/gitea-postgres exposed

   2. Verify that the PostgreSQL service uses the gitea-postgres name and the 5432 port.

      [student@workstation ~]$ oc get svc
      NAME             TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)    AGE
      gitea-postgres   ClusterIP   172.30.124.174   <none>        5432/TCP   50s

5. Configure networking for the Gitea application.

   1. Expose the application within the RHOCP cluster.

      [student@workstation ~]$ oc expose deployment gitea
      service/gitea exposed

   2. Expose the gitea service for external access.

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

6. Test your application functionality.

   1. Verify the external URL for your application.

      [student@workstation ~]$ oc get route
      NAME    HOST/PORT                                  SERVICES   PORT   WILDCARD
      gitea   gitea-ocp-multipod.apps.ocp4.example.com   gitea      3030   None

   2. In a web browser, open the gitea-ocp-multipod.apps.ocp4.example.com URL and use the following configuration:

      • Database type: PostgreSQL

      • Host: gitea-postgres:5432

      • Username: gitea

      • Password: gitea

      • Database name: gitea

      • Server Domain: gitea-ocp-multipod.apps.ocp4.example.com

      • Gitea Base URL: http://gitea-ocp-multipod.apps.ocp4.example.com

      Then, click Install Gitea.

      This step is successful if you see the login page.

   3. Optionally, click Register to create a user and log in.

      Figure 8.6: A running Gitea instance when logged in