{"id":50076,"date":"2026-06-23T06:48:21","date_gmt":"2026-06-23T06:48:21","guid":{"rendered":"https:\/\/www.devopsschool.com\/blog\/?p=50076"},"modified":"2026-06-23T06:48:23","modified_gmt":"2026-06-23T06:48:23","slug":"openshift-lab-9-work-with-databases-in-the-openshift-web-console","status":"publish","type":"post","link":"https:\/\/www.devopsschool.com\/blog\/openshift-lab-9-work-with-databases-in-the-openshift-web-console\/","title":{"rendered":"OpenShift Lab 9: Work with Databases in the OpenShift Web Console"},"content":{"rendered":"\n

Lab Goal<\/h2>\n\n\n\n

In this lab, you will deploy a PostgreSQL database on OpenShift Local using the OpenShift web console. You will create the database using modern OpenShift resources such as Deployment, Service, Secret, ConfigMap, and PersistentVolumeClaim.<\/p>\n\n\n\n

This lab replaces the older MongoDB web-console lab that used an outdated MongoDB image, an ephemeral database template, hard-coded credentials, and DeploymentConfig. The new lab uses current OpenShift-friendly practices.<\/p>\n\n\n\n

By the end of this lab, you will understand how an application or client pod connects to a database inside OpenShift using internal service discovery.<\/p>\n\n\n\n

\n\n\n\n

What You Will Learn<\/h2>\n\n\n\n

You will learn how to:<\/p>\n\n\n\n

    \n
  1. Start OpenShift Local.<\/li>\n\n\n\n
  2. Log in to the OpenShift web console.<\/li>\n\n\n\n
  3. Create a new project.<\/li>\n\n\n\n
  4. Create a PostgreSQL database using the web console.<\/li>\n\n\n\n
  5. Store database credentials in a Secret.<\/li>\n\n\n\n
  6. Store non-sensitive database configuration in a ConfigMap.<\/li>\n\n\n\n
  7. Create persistent storage using a PersistentVolumeClaim.<\/li>\n\n\n\n
  8. Expose the database internally using a Service.<\/li>\n\n\n\n
  9. Deploy a database client pod.<\/li>\n\n\n\n
  10. Connect to PostgreSQL from inside the OpenShift cluster.<\/li>\n\n\n\n
  11. Create a table and insert test data.<\/li>\n\n\n\n
  12. Verify that data survives a database pod restart.<\/li>\n\n\n\n
  13. Validate everything using optional oc<\/code> commands.<\/li>\n\n\n\n
  14. Clean up the lab environment.<\/li>\n<\/ol>\n\n\n\n
    \n\n\n\n

    Lab Architecture<\/h2>\n\n\n\n

    In this lab, you will create the following OpenShift resources:<\/p>\n\n\n\n

    Resource<\/th>Name<\/th>Purpose<\/th><\/tr><\/thead>
    Project<\/td>lab9-db-web-console<\/code><\/td>Isolated namespace for this lab<\/td><\/tr>
    Secret<\/td>postgresql-secret<\/code><\/td>Stores database username, password, and database name<\/td><\/tr>
    ConfigMap<\/td>postgresql-config<\/code><\/td>Stores non-sensitive PostgreSQL settings<\/td><\/tr>
    PersistentVolumeClaim<\/td>postgresql-data<\/code><\/td>Provides persistent database storage<\/td><\/tr>
    Deployment<\/td>postgresql<\/code><\/td>Runs the PostgreSQL database pod<\/td><\/tr>
    Service<\/td>postgresql<\/code><\/td>Provides stable internal DNS name for the database<\/td><\/tr>
    Deployment<\/td>db-client<\/code><\/td>Runs a client pod used to test database connectivity<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
    \n\n\n\n

    Why This Lab Uses PostgreSQL Instead of the Old MongoDB Template<\/h2>\n\n\n\n

    The older lab used an old MongoDB 3.6 template and an ephemeral database. That approach is not ideal for a current OpenShift student lab.<\/p>\n\n\n\n

    This replacement lab uses PostgreSQL because:<\/p>\n\n\n\n

      \n
    1. PostgreSQL is commonly used in enterprise application environments.<\/li>\n\n\n\n
    2. The database runs as a standard Kubernetes Deployment.<\/li>\n\n\n\n
    3. Credentials are stored in a Secret.<\/li>\n\n\n\n
    4. Non-sensitive settings are stored in a ConfigMap.<\/li>\n\n\n\n
    5. Data is stored on a PersistentVolumeClaim.<\/li>\n\n\n\n
    6. Students can clearly understand how applications connect to databases through internal Services.<\/li>\n<\/ol>\n\n\n\n
      \n\n\n\n

      Important Concept<\/h2>\n\n\n\n

      A database should usually not be exposed publicly through an OpenShift Route.<\/p>\n\n\n\n

      In OpenShift:<\/p>\n\n\n\n

      Resource<\/th>Used For<\/th><\/tr><\/thead>
      Service<\/td>Internal communication inside the cluster<\/td><\/tr>
      Route<\/td>External HTTP\/HTTPS access to web applications<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

      In this lab, PostgreSQL will only be available inside the OpenShift cluster through the internal service name:<\/p>\n\n\n

      postgresql\n<\/code><\/span><\/pre>\n\n\n
      The database will not be exposed using a Route.<\/p>\n\n\n\n
      \n\n\n\n
      Part 1: Prerequisites<\/h1>\n\n\n\n
      Required Tools<\/h2>\n\n\n\n
      You need the following tools installed on your machine:<\/p>\n\n\n\n
        \n
      1. OpenShift Local<\/li>\n\n\n\n
      2. crc<\/code> command<\/li>\n\n\n\n
      3. oc<\/code> command<\/li>\n\n\n\n
      4. A browser<\/li>\n\n\n\n
      5. At least 4 CPUs and enough memory available for OpenShift Local<\/li>\n<\/ol>\n\n\n\n
        \n\n\n\n
        Recommended OpenShift Local Configuration<\/h2>\n\n\n\n
        OpenShift Local with the OpenShift preset requires a local single-node OpenShift cluster. For smooth lab work, use at least:<\/p>\n\n\n\n
        Resource<\/th>Recommended<\/th><\/tr><\/thead>
        CPU<\/td>4 or more<\/td><\/tr>
        Memory<\/td>12 GB or more<\/td><\/tr>
        Disk<\/td>35 GB or more<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
        \n\n\n\n
        Part 2: Start OpenShift Local<\/h1>\n\n\n\n
        Open a terminal on your machine.<\/p>\n\n\n\n
        Check your OpenShift Local version:<\/p>\n\n\n
        crc version\n<\/code><\/span><\/pre>\n\n\n
        Set the OpenShift preset:<\/p>\n\n\n
        crc config set<\/span> preset openshift\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
        Run the setup command:<\/p>\n\n\n
        crc setup\n<\/code><\/span><\/pre>\n\n\n
        Start OpenShift Local:<\/p>\n\n\n
        crc start\n<\/code><\/span><\/pre>\n\n\n
        The start command may take several minutes.<\/p>\n\n\n\n
        When the cluster starts successfully, OpenShift Local prints login information for the web console and command line.<\/p>\n\n\n\n
        To view the credentials again, run:<\/p>\n\n\n
        crc console<\/span> --credentials\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
        To open the web console, run:<\/p>\n\n\n
        crc console<\/span>\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
        \n\n\n\n
        Part 3: Configure the oc<\/code> CLI<\/h1>\n\n\n\n
        OpenShift Local provides the oc<\/code> CLI environment command.<\/p>\n\n\n\n
        Run:<\/p>\n\n\n
        crc oc-env\n<\/code><\/span><\/pre>\n\n\n
        On Linux or macOS, apply the environment using:<\/p>\n\n\n
        eval<\/span> $(crc oc-env)\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
        Now log in as the developer user.<\/p>\n\n\n\n
        Use the password shown by:<\/p>\n\n\n
        crc console<\/span> --credentials\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
        Login command:<\/p>\n\n\n
        oc login -u developer https:\/\/api.crc.testing:6443<\/span>\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
        Verify login:<\/p>\n\n\n
        oc whoami\n<\/code><\/span><\/pre>\n\n\n
        Expected output:<\/p>\n\n\n
        developer\n<\/code><\/span><\/pre>\n\n\n
        Check the cluster:<\/p>\n\n\n
        oc get<\/span> nodes\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
        Expected result:<\/p>\n\n\n
        NAME                 STATUS   ROLES                         AGE   VERSION\ncrc-xxxxx-master-0   Ready    control-plane,master,worker    ...\n<\/code><\/span><\/pre>\n\n\n
        The exact node name and version may be different.<\/p>\n\n\n\n
        \n\n\n\n
        Part 4: Create a New Project from the Web Console<\/h1>\n\n\n\n
          \n
        1. Open the OpenShift web console.<\/li>\n\n\n\n
        2. Log in as:<\/li>\n<\/ol>\n\n\n
          Username: developer\nPassword<\/span>: Use the password from<\/span> crc console<\/span> --credentials\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
            \n
          1. Switch to the Developer<\/strong> perspective.<\/li>\n\n\n\n
          2. Click Project<\/strong> dropdown.<\/li>\n\n\n\n
          3. Click Create Project<\/strong>.<\/li>\n\n\n\n
          4. Enter the following project name:<\/li>\n<\/ol>\n\n\n
            lab9-db-web-console<\/span>\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
              \n
            1. Click Create<\/strong>.<\/li>\n<\/ol>\n\n\n\n
              You now have a separate OpenShift project for this lab.<\/p>\n\n\n\n
              \n\n\n\n
              Part 5: Create Database Resources Using Import YAML<\/h1>\n\n\n\n
              In the OpenShift web console:<\/p>\n\n\n\n
                \n
              1. Make sure you are in the project:<\/li>\n<\/ol>\n\n\n
                lab9-db-web-console<\/span>\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                  \n
                1. Go to +Add<\/strong>.<\/li>\n\n\n\n
                2. Choose Import YAML<\/strong>.<\/li>\n\n\n\n
                3. Paste the full YAML below.<\/li>\n\n\n\n
                4. Click Create<\/strong>.<\/li>\n<\/ol>\n\n\n\n
                  \n\n\n\n
                  YAML: PostgreSQL Database, Secret, ConfigMap, PVC, Service, and Client Pod<\/h2>\n\n\n
                  apiVersion: v1\nkind<\/span>: Secret\nmetadata<\/span>:\n  name: postgresql-secret\n  labels<\/span>:\n    app.kubernetes.io\/name: postgresql\n    app.kubernetes.io\/part-of<\/span>: lab9-database-demo\ntype<\/span>: Opaque\nstringData<\/span>:\n  POSTGRESQL_USER: appuser\n  POSTGRESQL_PASSWORD<\/span>: ChangeMeLab9!\n  POSTGRESQL_DATABASE: appdb\n---\napiVersion: v1\nkind<\/span>: ConfigMap\nmetadata<\/span>:\n  name: postgresql-config\n  labels<\/span>:\n    app.kubernetes.io\/name: postgresql\n    app.kubernetes.io\/part-of<\/span>: lab9-database-demo\ndata<\/span>:\n  POSTGRESQL_MAX_CONNECTIONS: \"50\"<\/span>\n  POSTGRESQL_SHARED_BUFFERS<\/span>: \"64MB\"<\/span>\n---\napiVersion: v1\nkind<\/span>: PersistentVolumeClaim\nmetadata<\/span>:\n  name: postgresql-data\n  labels<\/span>:\n    app.kubernetes.io\/name: postgresql\n    app.kubernetes.io\/part-of<\/span>: lab9-database-demo\nspec<\/span>:\n  accessModes:\n    - ReadWriteOnce\n  resources<\/span>:\n    requests:\n      storage: 1<\/span>Gi\n---\napiVersion: apps\/v1\nkind<\/span>: Deployment\nmetadata<\/span>:\n  name: postgresql\n  labels<\/span>:\n    app: postgresql\n    app.kubernetes.io\/name: postgresql\n    app.kubernetes.io\/part-of<\/span>: lab9-database-demo\nspec<\/span>:\n  replicas: 1<\/span>\n  selector<\/span>:\n    matchLabels:\n      app: postgresql\n  strategy<\/span>:\n    type: Recreate\n  template<\/span>:\n    metadata:\n      labels:\n        app: postgresql\n        app.kubernetes.io\/name: postgresql\n        app.kubernetes.io\/part-of<\/span>: lab9-database-demo\n    spec<\/span>:\n      terminationGracePeriodSeconds: 30<\/span>\n      containers<\/span>:\n        - name: postgresql\n          image<\/span>: registry.redhat.io\/rhel9\/postgresql-15<\/span>:latest\n          imagePullPolicy<\/span>: IfNotPresent\n          ports<\/span>:\n            - name: postgresql\n              containerPort<\/span>: 5432<\/span>\n              protocol<\/span>: TCP\n          env<\/span>:\n            - name: POSTGRESQL_USER\n              valueFrom<\/span>:\n                secretKeyRef:\n                  name: postgresql-secret\n                  key<\/span>: POSTGRESQL_USER\n            - name: POSTGRESQL_PASSWORD\n              valueFrom<\/span>:\n                secretKeyRef:\n                  name: postgresql-secret\n                  key<\/span>: POSTGRESQL_PASSWORD\n            - name: POSTGRESQL_DATABASE\n              valueFrom<\/span>:\n                secretKeyRef:\n                  name: postgresql-secret\n                  key<\/span>: POSTGRESQL_DATABASE\n            - name: POSTGRESQL_MAX_CONNECTIONS\n              valueFrom<\/span>:\n                configMapKeyRef:\n                  name: postgresql-config\n                  key<\/span>: POSTGRESQL_MAX_CONNECTIONS\n            - name: POSTGRESQL_SHARED_BUFFERS\n              valueFrom<\/span>:\n                configMapKeyRef:\n                  name: postgresql-config\n                  key<\/span>: POSTGRESQL_SHARED_BUFFERS\n            - name: POSTGRESQL_LOG_DESTINATION\n              value<\/span>: \/dev\/<\/span>stderr\n          resources<\/span>:\n            requests:\n              cpu: 100<\/span>m\n              memory<\/span>: 256<\/span>Mi\n            limits<\/span>:\n              cpu: 500<\/span>m\n              memory<\/span>: 768<\/span>Mi\n          readinessProbe<\/span>:\n            tcpSocket:\n              port: 5432<\/span>\n            initialDelaySeconds<\/span>: 10<\/span>\n            periodSeconds<\/span>: 10<\/span>\n            timeoutSeconds<\/span>: 2<\/span>\n          livenessProbe<\/span>:\n            tcpSocket:\n              port: 5432<\/span>\n            initialDelaySeconds<\/span>: 30<\/span>\n            periodSeconds<\/span>: 20<\/span>\n            timeoutSeconds<\/span>: 2<\/span>\n          securityContext<\/span>:\n            allowPrivilegeEscalation: false<\/span>\n            capabilities<\/span>:\n              drop:\n                - ALL\n          volumeMounts<\/span>:\n            - name: postgresql-data\n              mountPath<\/span>: \/var\/<\/span>lib\/pgsql\/data\n      volumes<\/span>:\n        - name: postgresql-data\n          persistentVolumeClaim<\/span>:\n            claimName: postgresql-data\n---\napiVersion: v1\nkind<\/span>: Service\nmetadata<\/span>:\n  name: postgresql\n  labels<\/span>:\n    app: postgresql\n    app.kubernetes.io\/name: postgresql\n    app.kubernetes.io\/part-of<\/span>: lab9-database-demo\nspec<\/span>:\n  type: ClusterIP\n  selector<\/span>:\n    app: postgresql\n  ports<\/span>:\n    - name: postgresql\n      protocol<\/span>: TCP\n      port<\/span>: 5432<\/span>\n      targetPort<\/span>: 5432<\/span>\n---\napiVersion: apps\/v1\nkind<\/span>: Deployment\nmetadata<\/span>:\n  name: db-client\n  labels<\/span>:\n    app: db-client\n    app.kubernetes.io\/name: db-client\n    app.kubernetes.io\/part-of<\/span>: lab9-database-demo\nspec<\/span>:\n  replicas: 1<\/span>\n  selector<\/span>:\n    matchLabels:\n      app: db-client\n  template<\/span>:\n    metadata:\n      labels:\n        app: db-client\n        app.kubernetes.io\/name: db-client\n        app.kubernetes.io\/part-of<\/span>: lab9-database-demo\n    spec<\/span>:\n      containers:\n        - name: db-client\n          image<\/span>: registry.redhat.io\/rhel9\/postgresql-15<\/span>:latest\n          imagePullPolicy<\/span>: IfNotPresent\n          command<\/span>:\n            - \/bin\/<\/span>bash\n            - -c\n          args<\/span>:\n            - echo \"db-client is ready\"<\/span>; while<\/span> true<\/span>; do<\/span> sleep 3600<\/span>; done\n          env<\/span>:\n            - name: PGHOST\n              value<\/span>: postgresql\n            - name: PGPORT\n              value<\/span>: \"5432\"<\/span>\n            - name: PGDATABASE\n              valueFrom<\/span>:\n                secretKeyRef:\n                  name: postgresql-secret\n                  key<\/span>: POSTGRESQL_DATABASE\n            - name: PGUSER\n              valueFrom<\/span>:\n                secretKeyRef:\n                  name: postgresql-secret\n                  key<\/span>: POSTGRESQL_USER\n            - name: PGPASSWORD\n              valueFrom<\/span>:\n                secretKeyRef:\n                  name: postgresql-secret\n                  key<\/span>: POSTGRESQL_PASSWORD\n          resources<\/span>:\n            requests:\n              cpu: 50<\/span>m\n              memory<\/span>: 128<\/span>Mi\n            limits<\/span>:\n              cpu: 250<\/span>m\n              memory<\/span>: 256<\/span>Mi\n          securityContext<\/span>:\n            allowPrivilegeEscalation: false<\/span>\n            capabilities<\/span>:\n              drop:\n                - ALL\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                  \n\n\n\n
                  Part 6: Understand the YAML<\/h1>\n\n\n\n
                  1. Secret<\/h2>\n\n\n
                  kind: Secret\nmetadata:\n  name: postgresql-secret\n<\/code><\/span><\/pre>\n\n\n
                  The Secret stores sensitive database values:<\/p>\n\n\n
                  POSTGRESQL_USER\nPOSTGRESQL_PASSWORD\nPOSTGRESQL_DATABASE\n<\/code><\/span><\/pre>\n\n\n
                  The PostgreSQL pod uses these values when the database is initialized.<\/p>\n\n\n\n
                  The client pod also uses these values to connect to the database.<\/p>\n\n\n\n
                  In real projects, never hard-code production passwords in YAML files committed to Git.<\/p>\n\n\n\n
                  For production, use a secret management approach such as:<\/p>\n\n\n\n
                    \n
                  1. External Secrets Operator<\/li>\n\n\n\n
                  2. HashiCorp Vault<\/li>\n\n\n\n
                  3. AWS Secrets Manager<\/li>\n\n\n\n
                  4. Azure Key Vault<\/li>\n\n\n\n
                  5. Google Secret Manager<\/li>\n\n\n\n
                  6. Sealed Secrets<\/li>\n\n\n\n
                  7. GitOps secret encryption tools<\/li>\n<\/ol>\n\n\n\n
                    For this beginner lab, the password is visible so students can understand the workflow.<\/p>\n\n\n\n
                    \n\n\n\n
                    2. ConfigMap<\/h2>\n\n\n
                    kind: ConfigMap\nmetadata:\n  name: postgresql-config\n<\/code><\/span><\/pre>\n\n\n
                    The ConfigMap stores non-sensitive settings:<\/p>\n\n\n
                    POSTGRESQL_MAX_CONNECTIONS\nPOSTGRESQL_SHARED_BUFFERS\n<\/code><\/span><\/pre>\n\n\n
                    Use ConfigMaps for application configuration that is not secret.<\/p>\n\n\n\n
                    Examples:<\/p>\n\n\n
                    APP_MODE=dev\nLOG_LEVEL=debug\nDATABASE_HOST=postgresql\nDATABASE_PORT=5432\n<\/code><\/span><\/pre>\n\n\n
                    Do not store passwords, tokens, or private keys in ConfigMaps.<\/p>\n\n\n\n
                    \n\n\n\n
                    3. PersistentVolumeClaim<\/h2>\n\n\n
                    kind: PersistentVolumeClaim\nmetadata:\n  name: postgresql-data\n<\/code><\/span><\/pre>\n\n\n
                    The PersistentVolumeClaim requests storage for the database.<\/p>\n\n\n\n
                    The PostgreSQL database writes its data to:<\/p>\n\n\n
                    \/var<\/span>\/lib\/pgsql\/data\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                    That directory is backed by the PVC.<\/p>\n\n\n\n
                    This means the data can survive a pod restart or pod recreation.<\/p>\n\n\n\n
                    \n\n\n\n
                    4. PostgreSQL Deployment<\/h2>\n\n\n
                    kind: Deployment\nmetadata:\n  name: postgresql\n<\/code><\/span><\/pre>\n\n\n
                    The Deployment creates and manages the PostgreSQL pod.<\/p>\n\n\n\n
                    The lab uses:<\/p>\n\n\n
                    strategy:\n  type: Recreate\n<\/code><\/span><\/pre>\n\n\n
                    This is useful for a single-instance database because the old pod is stopped before a new pod is started.<\/p>\n\n\n\n
                    \n\n\n\n
                    5. PostgreSQL Service<\/h2>\n\n\n
                    kind: Service\nmetadata:\n  name: postgresql\n<\/code><\/span><\/pre>\n\n\n
                    The Service provides a stable internal name for the database.<\/p>\n\n\n\n
                    Other pods in the same project can connect to PostgreSQL using:<\/p>\n\n\n
                    postgresql<\/span>:5432<\/span>\n<\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
                    The client pod uses:<\/p>\n\n\n
                    PGHOST=postgresql\n<\/code><\/span><\/pre>\n\n\n
                    This is OpenShift\/Kubernetes service discovery.<\/p>\n\n\n\n
                    \n\n\n\n
                    6. DB Client Deployment<\/h2>\n\n\n
                    kind: Deployment\nmetadata:\n  name: db-client\n<\/code><\/span><\/pre>\n\n\n
                    The db-client pod is a test pod. It is not the database. It is used to test database connectivity from inside the cluster.<\/p>\n\n\n\n
                    The client pod has PostgreSQL client tools available, including:<\/p>\n\n\n
                    psql\n<\/code><\/span><\/pre>\n\n\n
                    You will use this pod to connect to the PostgreSQL Service.<\/p>\n\n\n\n
                    \n\n\n\n
                    Part 7: Verify Resources in the Web Console<\/h1>\n\n\n\n
                    After clicking Create<\/strong>, go to:<\/p>\n\n\n
                    Developer perspective > Topology\n<\/code><\/span><\/pre>\n\n\n
                    You should see two workloads:<\/p>\n\n\n
                    postgresql\ndb-client\n<\/code><\/span><\/pre>\n\n\n
                    Click the postgresql<\/code> workload.<\/p>\n\n\n\n
                    Check:<\/p>\n\n\n\n
                      \n
                    1. Pod status<\/li>\n\n\n\n
                    2. Deployment status<\/li>\n\n\n\n
                    3. Service<\/li>\n\n\n\n
                    4. Logs<\/li>\n\n\n\n
                    5. Events<\/li>\n<\/ol>\n\n\n\n
                      The PostgreSQL pod should eventually show as running.<\/p>\n\n\n\n
                      Click the db-client<\/code> workload.<\/p>\n\n\n\n
                      Check that its pod is also running.<\/p>\n\n\n\n
                      \n\n\n\n
                      Part 8: Verify Resources Using CLI<\/h1>\n\n\n\n
                      Run:<\/p>\n\n\n
                      oc project lab9-db-web-console<\/span>\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                      List all major resources:<\/p>\n\n\n
                      oc get<\/span> deploy,po,svc,pvc,secret,cm\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                      Expected resources:<\/p>\n\n\n
                      deployment.apps\/postgresql\ndeployment.apps\/db-client\n\npod\/postgresql-xxxxx\npod\/db-client-xxxxx\n\nservice\/postgresql\n\npersistentvolumeclaim\/postgresql-data\n\nsecret\/postgresql-secret\n\nconfigmap\/postgresql-config\n<\/code><\/span><\/pre>\n\n\n
                      Check rollout status:<\/p>\n\n\n
                      oc rollout status deployment\/postgresql\n<\/code><\/span><\/pre>\n\n\n
                      Expected output:<\/p>\n\n\n
                      deployment \"postgresql\"<\/span> successfully rolled out\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                      Check client rollout:<\/p>\n\n\n
                      oc rollout status deployment\/db-client\n<\/code><\/span><\/pre>\n\n\n
                      Expected output:<\/p>\n\n\n
                      deployment \"db-client\"<\/span> successfully rolled out\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                      Check the PVC:<\/p>\n\n\n
                      oc get<\/span> pvc postgresql-data\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                      Expected output:<\/p>\n\n\n
                      NAME              STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS\npostgresql-data   Bound    pvc-xxxxxx                                  1Gi        RWO            ...\n<\/code><\/span><\/pre>\n\n\n
                      The STATUS<\/code> should be:<\/p>\n\n\n
                      Bound\n<\/code><\/span><\/pre>\n\n\n
                      \n\n\n\n
                      Part 9: Check PostgreSQL Logs<\/h1>\n\n\n\n
                      From the web console:<\/p>\n\n\n\n
                        \n
                      1. Go to Developer<\/strong> perspective.<\/li>\n\n\n\n
                      2. Open Topology<\/strong>.<\/li>\n\n\n\n
                      3. Click postgresql<\/code>.<\/li>\n\n\n\n
                      4. Click the pod.<\/li>\n\n\n\n
                      5. Open the Logs<\/strong> tab.<\/li>\n<\/ol>\n\n\n\n
                        Or use CLI:<\/p>\n\n\n
                        oc logs deployment\/postgresql\n<\/code><\/span><\/pre>\n\n\n
                        You should see PostgreSQL initialization and startup messages.<\/p>\n\n\n\n
                        The exact log output may vary, but it should indicate that PostgreSQL started successfully.<\/p>\n\n\n\n
                        \n\n\n\n
                        Part 10: Connect to PostgreSQL from the Web Console Terminal<\/h1>\n\n\n\n
                        Now connect to the database from inside the OpenShift cluster.<\/p>\n\n\n\n
                        In the web console:<\/p>\n\n\n\n
                          \n
                        1. Go to Developer<\/strong> perspective.<\/li>\n\n\n\n
                        2. Open Topology<\/strong>.<\/li>\n\n\n\n
                        3. Click db-client<\/code>.<\/li>\n\n\n\n
                        4. Open the running pod.<\/li>\n\n\n\n
                        5. Click the Terminal<\/strong> tab.<\/li>\n<\/ol>\n\n\n\n
                          Inside the terminal, run:<\/p>\n\n\n
                          psql -h \"$PGHOST\"<\/span> -U \"$PGUSER\"<\/span> -d \"$PGDATABASE\"<\/span> -c \"SELECT version();\"<\/span>\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                          Expected output should include PostgreSQL version information.<\/p>\n\n\n\n
                          Example:<\/p>\n\n\n
                          PostgreSQL<\/span> 15.x<\/span>\n<\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
                          Now check the current database and current user:<\/p>\n\n\n
                          psql -h \"$PGHOST\"<\/span> -U \"$PGUSER\"<\/span> -d \"$PGDATABASE\"<\/span> -c \"SELECT current_database(), current_user;\"<\/span>\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                          Expected output:<\/p>\n\n\n
                           current_database | current_user\n------------------+--------------\n appdb            | appuser\n<\/code><\/span><\/pre>\n\n\n
                          This confirms that the client pod can connect to the PostgreSQL database using the internal service name.<\/p>\n\n\n\n
                          \n\n\n\n
                          Part 11: Create a Table and Insert Data<\/h1>\n\n\n\n
                          From the db-client<\/code> pod terminal, run:<\/p>\n\n\n
                          psql -h \"$PGHOST\"<\/span> -U \"$PGUSER\"<\/span> -d \"$PGDATABASE\"<\/span>\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                          You should now be inside the PostgreSQL shell.<\/p>\n\n\n\n
                          You will see a prompt similar to:<\/p>\n\n\n
                          appdb=>\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
                          Create a table:<\/p>\n\n\n
                          CREATE TABLE IF<\/span> NOT EXISTS lab9_messages (\n  id SERIAL PRIMARY KEY,\n  student_name TEXT NOT NULL<\/span>,\n  message TEXT NOT NULL<\/span>,\n  created_at TIMESTAMP DEFAULT<\/span> CURRENT_TIMESTAMP\n);\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
                          Insert a row:<\/p>\n\n\n
                          INSERT INTO lab9_messages(student_name, message)\nVALUES ('student01'<\/span>, 'Hello from OpenShift Local Lab 9'<\/span>);\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                          Query the table:<\/p>\n\n\n
                          SELECT id, student_name, message, created_at\nFROM lab9_messages\nORDER BY id DESC\nLIMIT 5;\n<\/code><\/span><\/pre>\n\n\n
                          Expected output:<\/p>\n\n\n
                           id | student_name |              message               |         created_at\n----+--------------+------------------------------------+----------------------------\n  1<\/span> | student01    | Hello from<\/span> OpenShift Local Lab 9<\/span>   | ...\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                          Exit PostgreSQL:<\/p>\n\n\n
                          \\q\n<\/code><\/span><\/pre>\n\n\n
                          \n\n\n\n
                          Part 12: One-Line SQL Test Alternative<\/h1>\n\n\n\n
                          If copy-paste into the PostgreSQL shell is difficult, run the following one-line commands from the db-client<\/code> pod terminal.<\/p>\n\n\n\n
                          Create the table:<\/p>\n\n\n
                          psql -h \"$PGHOST\"<\/span> -U \"$PGUSER\"<\/span> -d \"$PGDATABASE\"<\/span> -c \"CREATE TABLE IF NOT EXISTS lab9_messages (id SERIAL PRIMARY KEY, student_name TEXT NOT NULL, message TEXT NOT NULL, created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP);\"<\/span>\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                          Insert a row:<\/p>\n\n\n
                          psql -h \"$PGHOST\"<\/span> -U \"$PGUSER\"<\/span> -d \"$PGDATABASE\"<\/span> -c \"INSERT INTO lab9_messages(student_name, message) VALUES ('student01', 'Hello from OpenShift Local Lab 9');\"<\/span>\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                          Query rows:<\/p>\n\n\n
                          psql -h \"$PGHOST\"<\/span> -U \"$PGUSER\"<\/span> -d \"$PGDATABASE\"<\/span> -c \"SELECT id, student_name, message, created_at FROM lab9_messages ORDER BY id DESC LIMIT 5;\"<\/span>\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                          \n\n\n\n
                          Part 13: Verify Database Connectivity Using CLI<\/h1>\n\n\n\n
                          You can also run the SQL test from your local terminal using oc exec<\/code>.<\/p>\n\n\n\n
                          First, find the db-client pod:<\/p>\n\n\n
                          oc get<\/span> pods -l app=db-client\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                          Store the pod name in a variable:<\/p>\n\n\n
                          DB_CLIENT_POD=$(oc get pod -l app=db-client -o jsonpath='{.items[0].metadata.name}'<\/span>)\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
                          Run a database query:<\/p>\n\n\n
                          oc exec \"$DB_CLIENT_POD\"<\/span> -- bash -lc 'psql -h \"$PGHOST\" -U \"$PGUSER\" -d \"$PGDATABASE\" -c \"SELECT current_database(), current_user;\"'<\/span>\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                          Expected output:<\/p>\n\n\n
                           current_database | current_user\n------------------+--------------\n appdb            | appuser\n<\/code><\/span><\/pre>\n\n\n
                          Create the table:<\/p>\n\n\n
                          oc exec \"$DB_CLIENT_POD\"<\/span> -- bash -lc 'psql -h \"$PGHOST\" -U \"$PGUSER\" -d \"$PGDATABASE\" -c \"CREATE TABLE IF NOT EXISTS lab9_messages (id SERIAL PRIMARY KEY, student_name TEXT NOT NULL, message TEXT NOT NULL, created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP);\"'<\/span>\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                          Insert a row:<\/p>\n\n\n
                          oc exec \"$DB_CLIENT_POD\"<\/span> -- bash -lc 'psql -h \"$PGHOST\" -U \"$PGUSER\" -d \"$PGDATABASE\" -c \"INSERT INTO lab9_messages(student_name, message) VALUES ('<\/span>cli-user', '<\/span>Inserted using oc exec from<\/span> local terminal');\"'<\/span>\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                          Query the table:<\/p>\n\n\n
                          oc exec \"$DB_CLIENT_POD\"<\/span> -- bash -lc 'psql -h \"$PGHOST\" -U \"$PGUSER\" -d \"$PGDATABASE\" -c \"SELECT id, student_name, message, created_at FROM lab9_messages ORDER BY id DESC LIMIT 5;\"'<\/span>\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                          \n\n\n\n
                          Part 14: Prove That the Service Name Works<\/h1>\n\n\n\n
                          The database client connects to:<\/p>\n\n\n
                          postgresql\n<\/code><\/span><\/pre>\n\n\n
                          This name comes from the OpenShift Service:<\/p>\n\n\n
                          kind: Service\nmetadata:\n  name: postgresql\n<\/code><\/span><\/pre>\n\n\n
                          Inside the same OpenShift project, pods can reach the database using:<\/p>\n\n\n
                          postgresql<\/span>:5432<\/span>\n<\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
                          To inspect the service, run:<\/p>\n\n\n
                          oc describe service postgresql\n<\/code><\/span><\/pre>\n\n\n
                          You should see:<\/p>\n\n\n
                          Name<\/span>:              postgresql\nType<\/span>:              ClusterIP\nPort<\/span>:              postgresql  5432\/TCP\nEndpoints<\/span>:         ...\n<\/code><\/span>Code language:<\/span> HTTP<\/span> (<\/span>http<\/span>)<\/span><\/small><\/pre>\n\n\n
                          The Endpoints<\/code> field should point to the PostgreSQL pod IP and port.<\/p>\n\n\n\n
                          \n\n\n\n
                          Part 15: Prove That Data Persists After Pod Restart<\/h1>\n\n\n\n
                          A database should not lose data just because the pod restarts.<\/p>\n\n\n\n
                          In this lab, data is stored on the PersistentVolumeClaim named:<\/p>\n\n\n
                          postgresql-data\n<\/code><\/span><\/pre>\n\n\n
                          Option A: Restart from Web Console<\/h2>\n\n\n\n
                            \n
                          1. Go to Developer<\/strong> perspective.<\/li>\n\n\n\n
                          2. Open Topology<\/strong>.<\/li>\n\n\n\n
                          3. Click the postgresql<\/code> workload.<\/li>\n\n\n\n
                          4. Open the Deployment.<\/li>\n\n\n\n
                          5. Scale the Deployment to 0<\/code>.<\/li>\n\n\n\n
                          6. Wait until the PostgreSQL pod disappears.<\/li>\n\n\n\n
                          7. Scale the Deployment back to 1<\/code>.<\/li>\n\n\n\n
                          8. Wait until the new pod is running.<\/li>\n<\/ol>\n\n\n\n
                            Now go back to the db-client<\/code> pod terminal and run:<\/p>\n\n\n
                            psql -h \"$PGHOST\"<\/span> -U \"$PGUSER\"<\/span> -d \"$PGDATABASE\"<\/span> -c \"SELECT id, student_name, message, created_at FROM lab9_messages ORDER BY id DESC LIMIT 5;\"<\/span>\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                            Your previously inserted row should still exist.<\/p>\n\n\n\n
                            \n\n\n\n
                            Option B: Restart from CLI<\/h2>\n\n\n\n
                            Scale PostgreSQL down:<\/p>\n\n\n
                            oc scale deployment\/postgresql --replicas=0\n<\/code><\/span><\/pre>\n\n\n
                            Wait:<\/p>\n\n\n
                            oc get<\/span> pods -l app=postgresql\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                            Scale PostgreSQL back up:<\/p>\n\n\n
                            oc scale deployment\/postgresql --replicas=1\n<\/code><\/span><\/pre>\n\n\n
                            Wait for rollout:<\/p>\n\n\n
                            oc rollout status deployment\/postgresql\n<\/code><\/span><\/pre>\n\n\n
                            Query the data again:<\/p>\n\n\n
                            oc exec \"$DB_CLIENT_POD\"<\/span> -- bash -lc 'psql -h \"$PGHOST\" -U \"$PGUSER\" -d \"$PGDATABASE\" -c \"SELECT id, student_name, message, created_at FROM lab9_messages ORDER BY id DESC LIMIT 5;\"'<\/span>\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                            If the data is still visible, persistence is working.<\/p>\n\n\n\n
                            \n\n\n\n
                            Part 16: Check That No Route Was Created<\/h1>\n\n\n\n
                            A PostgreSQL database should usually remain internal to the cluster.<\/p>\n\n\n\n
                            Check routes:<\/p>\n\n\n
                            oc get<\/span> route\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                            Expected output:<\/p>\n\n\n
                            No resources found in<\/span> lab9-db-web-console<\/span> namespace.\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                            This is correct.<\/p>\n\n\n\n
                            The database is reachable inside OpenShift using the Service:<\/p>\n\n\n
                            postgresql<\/span>:5432<\/span>\n<\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
                            It is not exposed outside the cluster.<\/p>\n\n\n\n
                            \n\n\n\n
                            Part 17: Student Checkpoint<\/h1>\n\n\n\n
                            At this point, students should be able to answer:<\/p>\n\n\n\n
                            Question<\/th>Expected Answer<\/th><\/tr><\/thead>
                            What stores the database password?<\/td>Secret<\/td><\/tr>
                            What stores non-sensitive database settings?<\/td>ConfigMap<\/td><\/tr>
                            What gives the database a stable internal name?<\/td>Service<\/td><\/tr>
                            What stores database files?<\/td>PersistentVolumeClaim<\/td><\/tr>
                            What runs the PostgreSQL container?<\/td>Deployment<\/td><\/tr>
                            What is the internal database hostname?<\/td>postgresql<\/code><\/td><\/tr>
                            What is the PostgreSQL port?<\/td>5432<\/code><\/td><\/tr>
                            Should the database have an external Route?<\/td>No<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
                            \n\n\n\n
                            Part 18: Full CLI Validation Script<\/h1>\n\n\n\n
                            Run the following commands from your local terminal after logging in with oc<\/code>.<\/p>\n\n\n
                            oc project lab9-db-web-console\n\necho<\/span> \"Checking deployments...\"<\/span>\noc get deployment\n\necho<\/span> \"Checking pods...\"<\/span>\noc get pods -o wide\n\necho<\/span> \"Checking service...\"<\/span>\noc get svc postgresql\n\necho<\/span> \"Checking PVC...\"<\/span>\noc get pvc postgresql-data\n\necho<\/span> \"Checking Secret and ConfigMap...\"<\/span>\noc get secret postgresql-secret\noc get configmap postgresql-config\n\necho<\/span> \"Checking PostgreSQL rollout...\"<\/span>\noc rollout status deployment\/postgresql\n\necho<\/span> \"Checking db-client rollout...\"<\/span>\noc rollout status deployment\/db-client\n\necho<\/span> \"Finding db-client pod...\"<\/span>\nDB_CLIENT_POD=$(oc get pod -l app=db-client -o jsonpath='{.items[0].metadata.name}'<\/span>)\necho<\/span> \"DB client pod: $DB_CLIENT_POD\"<\/span>\n\necho<\/span> \"Running PostgreSQL connectivity test...\"<\/span>\noc exec \"$DB_CLIENT_POD\"<\/span> -- bash -lc 'psql -h \"$PGHOST\" -U \"$PGUSER\" -d \"$PGDATABASE\" -c \"SELECT current_database(), current_user;\"'<\/span>\n\necho<\/span> \"Checking existing lab table...\"<\/span>\noc exec \"$DB_CLIENT_POD\"<\/span> -- bash -lc 'psql -h \"$PGHOST\" -U \"$PGUSER\" -d \"$PGDATABASE\" -c \"SELECT COUNT(*) FROM lab9_messages;\"'<\/span>\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
                            Expected result:<\/p>\n\n\n\n
                              \n
                            1. Both Deployments should be available.<\/li>\n\n\n\n
                            2. Both pods should be running.<\/li>\n\n\n\n
                            3. The Service should exist.<\/li>\n\n\n\n
                            4. The PVC should be Bound.<\/li>\n\n\n\n
                            5. The PostgreSQL query should return appdb<\/code> and appuser<\/code>.<\/li>\n<\/ol>\n\n\n\n
                              \n\n\n\n
                              Part 19: Troubleshooting<\/h1>\n\n\n\n
                              Problem 1: PostgreSQL Pod Shows ImagePullBackOff<\/h2>\n\n\n\n
                              Check the pod:<\/p>\n\n\n
                              oc get<\/span> pods\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                              Describe the pod:<\/p>\n\n\n
                              oc describe pod -l app=postgresql\n<\/code><\/span><\/pre>\n\n\n
                              Check events:<\/p>\n\n\n
                              oc get<\/span> events --sort-by=.lastTimestamp\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                              Possible causes:<\/p>\n\n\n\n
                                \n
                              1. Red Hat registry pull secret issue.<\/li>\n\n\n\n
                              2. Network issue.<\/li>\n\n\n\n
                              3. Image name or tag not available in your environment.<\/li>\n<\/ol>\n\n\n\n
                                Possible fix for a classroom lab:<\/p>\n\n\n\n
                                Edit the Deployment image from:<\/p>\n\n\n
                                registry.redhat.io\/rhel9\/postgresql-15:latest\n<\/code><\/span><\/pre>\n\n\n
                                to:<\/p>\n\n\n
                                registry.access.redhat.com\/rhel9\/postgresql-15:latest\n<\/code><\/span><\/pre>\n\n\n
                                Then save and wait for the pod to restart.<\/p>\n\n\n\n
                                \n\n\n\n
                                Problem 2: PVC Is Pending<\/h2>\n\n\n\n
                                Check the PVC:<\/p>\n\n\n
                                oc get<\/span> pvc\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                                Describe the PVC:<\/p>\n\n\n
                                oc describe pvc postgresql-data\n<\/code><\/span><\/pre>\n\n\n
                                Check storage classes:<\/p>\n\n\n
                                oc get<\/span> storageclass\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                                Possible causes:<\/p>\n\n\n\n
                                  \n
                                1. No default StorageClass.<\/li>\n\n\n\n
                                2. OpenShift Local storage is not ready.<\/li>\n\n\n\n
                                3. Cluster is still starting.<\/li>\n<\/ol>\n\n\n\n
                                  In OpenShift Local, wait a few minutes and check again.<\/p>\n\n\n\n
                                  If there is no default StorageClass, ask the instructor to verify the OpenShift Local setup.<\/p>\n\n\n\n
                                  \n\n\n\n
                                  Problem 3: PostgreSQL Pod Is CrashLoopBackOff<\/h2>\n\n\n\n
                                  Check logs:<\/p>\n\n\n
                                  oc logs deployment\/postgresql\n<\/code><\/span><\/pre>\n\n\n
                                  Check previous logs:<\/p>\n\n\n
                                  oc logs deployment\/postgresql --previous\n<\/code><\/span><\/pre>\n\n\n
                                  Common causes:<\/p>\n\n\n\n
                                    \n
                                  1. Wrong environment variable names.<\/li>\n\n\n\n
                                  2. Invalid database initialization.<\/li>\n\n\n\n
                                  3. PVC already contains old incompatible data.<\/li>\n\n\n\n
                                  4. Password changed after the database was already initialized.<\/li>\n<\/ol>\n\n\n\n
                                    For a lab reset, delete and recreate the project:<\/p>\n\n\n
                                    oc delete<\/span> project lab9-db-web-console<\/span>\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                                    Then create the project again and reapply the YAML.<\/p>\n\n\n\n
                                    \n\n\n\n
                                    Problem 4: Password Authentication Failed<\/h2>\n\n\n\n
                                    If you changed the Secret after PostgreSQL was already initialized, the database password inside the persistent data directory may not change automatically.<\/p>\n\n\n\n
                                    For this beginner lab, the simplest reset is:<\/p>\n\n\n
                                    oc delete<\/span> project lab9-db-web-console<\/span>\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                                    Then recreate the project and apply the YAML again.<\/p>\n\n\n\n
                                    In production, password rotation requires a planned database credential rotation process.<\/p>\n\n\n\n
                                    \n\n\n\n
                                    Problem 5: psql<\/code> Command Not Found<\/h2>\n\n\n\n
                                    Make sure you are running the command inside the db-client<\/code> pod, not your laptop terminal.<\/p>\n\n\n\n
                                    From CLI:<\/p>\n\n\n
                                    DB_CLIENT_POD=$(oc get pod -l app=db-client -o jsonpath='{.items[0].metadata.name}'<\/span>)\noc exec -it \"$DB_CLIENT_POD\"<\/span> -- bash\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
                                    Then run:<\/p>\n\n\n
                                    psql --version\n<\/code><\/span><\/pre>\n\n\n
                                    \n\n\n\n
                                    Problem 6: No Route Found<\/h2>\n\n\n\n
                                    This is expected.<\/p>\n\n\n\n
                                    Run:<\/p>\n\n\n
                                    oc get<\/span> route\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                                    Expected output:<\/p>\n\n\n
                                    No resources found\n<\/code><\/span><\/pre>\n\n\n
                                    PostgreSQL is not an HTTP web application. It should normally be accessed internally through a Service, not exposed externally through a Route.<\/p>\n\n\n\n
                                    \n\n\n\n
                                    Part 20: Cleanup<\/h1>\n\n\n\n
                                    To delete all resources created in this lab, delete the project.<\/p>\n\n\n\n
                                    From the web console:<\/p>\n\n\n\n
                                      \n
                                    1. Switch to Administrator<\/strong> perspective.<\/li>\n\n\n\n
                                    2. Go to Home > Projects<\/strong>.<\/li>\n\n\n\n
                                    3. Find:<\/li>\n<\/ol>\n\n\n
                                      lab9-db-web-console<\/span>\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                                        \n
                                      1. Delete the project.<\/li>\n<\/ol>\n\n\n\n
                                        Or use CLI:<\/p>\n\n\n
                                        oc delete<\/span> project lab9-db-web-console<\/span>\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                                        Verify:<\/p>\n\n\n
                                        oc get<\/span> project lab9-db-web-console\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                                        The project should no longer exist.<\/p>\n\n\n\n
                                        \n\n\n\n
                                        Part 21: Lab Summary<\/h1>\n\n\n\n
                                        In this lab, you created a database-backed OpenShift environment using the web console.<\/p>\n\n\n\n
                                        You created:<\/p>\n\n\n\n
                                        Resource<\/th>Purpose<\/th><\/tr><\/thead>
                                        Secret<\/td>Stored database credentials<\/td><\/tr>
                                        ConfigMap<\/td>Stored non-sensitive database configuration<\/td><\/tr>
                                        PersistentVolumeClaim<\/td>Stored database data persistently<\/td><\/tr>
                                        Deployment<\/td>Ran the PostgreSQL database<\/td><\/tr>
                                        Service<\/td>Provided internal DNS name for PostgreSQL<\/td><\/tr>
                                        Client Deployment<\/td>Tested database connectivity<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
                                        You verified that:<\/p>\n\n\n\n
                                          \n
                                        1. PostgreSQL runs inside OpenShift.<\/li>\n\n\n\n
                                        2. The database is reachable by service name.<\/li>\n\n\n\n
                                        3. Credentials can be injected from a Secret.<\/li>\n\n\n\n
                                        4. Non-sensitive settings can be injected from a ConfigMap.<\/li>\n\n\n\n
                                        5. Database data persists after pod restart.<\/li>\n\n\n\n
                                        6. The database does not need an external Route.<\/li>\n<\/ol>\n\n\n\n
                                          \n\n\n\n
                                          Part 22: Lab Review Questions<\/h1>\n\n\n\n
                                          Question 1<\/h2>\n\n\n\n
                                          What is the purpose of a Secret in this lab?<\/p>\n\n\n\n
                                          Answer<\/h3>\n\n\n\n
                                          A Secret stores sensitive data such as the database username, password, and database name.<\/p>\n\n\n\n
                                          \n\n\n\n
                                          Question 2<\/h2>\n\n\n\n
                                          What is the purpose of a ConfigMap in this lab?<\/p>\n\n\n\n
                                          Answer<\/h3>\n\n\n\n
                                          A ConfigMap stores non-sensitive configuration such as database tuning values or application settings.<\/p>\n\n\n\n
                                          \n\n\n\n
                                          Question 3<\/h2>\n\n\n\n
                                          Why do we use a PersistentVolumeClaim?<\/p>\n\n\n\n
                                          Answer<\/h3>\n\n\n\n
                                          A PersistentVolumeClaim provides persistent storage so database data is not lost when the pod restarts.<\/p>\n\n\n\n
                                          \n\n\n\n
                                          Question 4<\/h2>\n\n\n\n
                                          Why does PostgreSQL use a Service?<\/p>\n\n\n\n
                                          Answer<\/h3>\n\n\n\n
                                          The Service provides a stable internal DNS name and port for other pods to connect to PostgreSQL.<\/p>\n\n\n\n
                                          \n\n\n\n
                                          Question 5<\/h2>\n\n\n\n
                                          Why did we not create a Route for PostgreSQL?<\/p>\n\n\n\n
                                          Answer<\/h3>\n\n\n\n
                                          A Route is mainly used to expose HTTP or HTTPS applications outside the cluster. PostgreSQL is a database service and should normally remain internal to the cluster.<\/p>\n\n\n\n
                                          \n\n\n\n
                                          Question 6<\/h2>\n\n\n\n
                                          What hostname does the client pod use to connect to PostgreSQL?<\/p>\n\n\n\n
                                          Answer<\/h3>\n\n\n
                                          postgresql\n<\/code><\/span><\/pre>\n\n\n
                                          \n\n\n\n
                                          Question 7<\/h2>\n\n\n\n
                                          What port does PostgreSQL listen on?<\/p>\n\n\n\n
                                          Answer<\/h3>\n\n\n
                                          5432\n<\/code><\/span><\/pre>\n\n\n
                                          \n\n\n\n
                                          Question 8<\/h2>\n\n\n\n
                                          Which resource runs the PostgreSQL container?<\/p>\n\n\n\n
                                          Answer<\/h3>\n\n\n\n
                                          Deployment.<\/p>\n\n\n\n
                                          \n\n\n\n
                                          Question 9<\/h2>\n\n\n\n
                                          Which resource stores the PostgreSQL data files?<\/p>\n\n\n\n
                                          Answer<\/h3>\n\n\n\n
                                          PersistentVolumeClaim.<\/p>\n\n\n\n
                                          \n\n\n\n
                                          Question 10<\/h2>\n\n\n\n
                                          What command can you use to verify the PostgreSQL pod logs?<\/p>\n\n\n\n
                                          Answer<\/h3>\n\n\n
                                          oc logs deployment\/postgresql\n<\/code><\/span><\/pre>\n\n\n
                                          \n\n\n\n
                                          Part 23: Instructor Notes<\/h1>\n\n\n\n
                                          This lab is designed as a replacement for older OpenShift database labs that used deprecated or outdated patterns.<\/p>\n\n\n\n
                                          The lab intentionally avoids:<\/p>\n\n\n\n
                                            \n
                                          1. MongoDB 3.6<\/li>\n\n\n\n
                                          2. DeploymentConfig<\/li>\n\n\n\n
                                          3. Ephemeral-only database storage<\/li>\n\n\n\n
                                          4. Hard-coded database URLs in application configuration<\/li>\n\n\n\n
                                          5. Exposing a database using a Route<\/li>\n\n\n\n
                                          6. Old OpenShift template-based database provisioning<\/li>\n<\/ol>\n\n\n\n
                                            The lab teaches current OpenShift concepts:<\/p>\n\n\n\n
                                              \n
                                            1. Deployment<\/li>\n\n\n\n
                                            2. Service<\/li>\n\n\n\n
                                            3. Secret<\/li>\n\n\n\n
                                            4. ConfigMap<\/li>\n\n\n\n
                                            5. PersistentVolumeClaim<\/li>\n\n\n\n
                                            6. Internal service discovery<\/li>\n\n\n\n
                                            7. Pod terminal access<\/li>\n\n\n\n
                                            8. CLI validation with oc exec<\/code><\/li>\n<\/ol>\n\n\n\n
                                              For production environments, students should also learn:<\/p>\n\n\n\n
                                                \n
                                              1. StatefulSet for production-grade stateful workloads<\/li>\n\n\n\n
                                              2. Database Operators<\/li>\n\n\n\n
                                              3. Automated backup and restore<\/li>\n\n\n\n
                                              4. Monitoring and alerting<\/li>\n\n\n\n
                                              5. Secret rotation<\/li>\n\n\n\n
                                              6. TLS for database connections<\/li>\n\n\n\n
                                              7. NetworkPolicy<\/li>\n\n\n\n
                                              8. Resource sizing<\/li>\n\n\n\n
                                              9. High availability<\/li>\n\n\n\n
                                              10. Disaster recovery<\/li>\n<\/ol>\n\n\n\n
                                                This lab is intentionally simple because it is focused on beginner-level OpenShift database fundamentals using the web console.<\/p>\n\n\n\n
                                                \n\n\n\n
                                                Part 24: Instructor Validation Checklist<\/h1>\n\n\n\n
                                                Before giving this lab to students, the instructor should run:<\/p>\n\n\n
                                                crc version\ncrc status\noc version\noc whoami\noc get<\/span> nodes\noc get<\/span> storageclass\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                                                Then apply the lab and validate:<\/p>\n\n\n
                                                oc project lab9-db-web-console<\/span>\noc get<\/span> deploy,po,svc,pvc,secret,cm\noc rollout status deployment\/postgresql\noc rollout status deployment\/db-client\noc logs deployment\/postgresql\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                                                Then run:<\/p>\n\n\n
                                                DB_CLIENT_POD=$(oc get pod -l app=db-client -o jsonpath='{.items[0].metadata.name}'<\/span>)\n\noc exec \"$DB_CLIENT_POD\"<\/span> -- bash -lc 'psql -h \"$PGHOST\" -U \"$PGUSER\" -d \"$PGDATABASE\" -c \"SELECT version();\"'<\/span>\n\noc exec \"$DB_CLIENT_POD\"<\/span> -- bash -lc 'psql -h \"$PGHOST\" -U \"$PGUSER\" -d \"$PGDATABASE\" -c \"SELECT current_database(), current_user;\"'<\/span>\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
                                                If these commands pass, the lab is ready for students.<\/p>\n\n\n\n
                                                \n\n\n\n
                                                Final Outcome<\/h1>\n\n\n\n
                                                You have successfully completed the updated OpenShift Lab 9.<\/p>\n\n\n\n
                                                You deployed a PostgreSQL database using the OpenShift web console, configured it using Secret and ConfigMap, stored its data on a PersistentVolumeClaim, exposed it internally using a Service, and tested database connectivity from another pod inside the cluster.<\/p>\n","protected":false},"excerpt":{"rendered":"
                                                Lab Goal In this lab, you will deploy a PostgreSQL database on OpenShift Local using the OpenShift web console. You will create the database using modern OpenShift… <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_joinchat":[],"footnotes":""},"categories":[5153],"tags":[],"class_list":["post-50076","post","type-post","status-publish","format-standard","hentry","category-openshift"],"_links":{"self":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts\/50076","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/comments?post=50076"}],"version-history":[{"count":3,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts\/50076\/revisions"}],"predecessor-version":[{"id":77154,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts\/50076\/revisions\/77154"}],"wp:attachment":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/media?parent=50076"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/categories?post=50076"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/tags?post=50076"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}