Chapter 6. Connecting applications to services

Procedure

1. In the Administrator perspective of the web console, navigate to Operators OperatorHub.
2. Use the Filter by keyword box to search for Service Binding Operator in the catalog. Click the Service Binding Operator tile.
3. Read the brief description about the Operator on the Service Binding Operator page. Click Install.

4. On the Install Operator page:

   1. Select All namespaces on the cluster (default) for the Installation Mode. This mode installs the Operator in the default openshift-operators namespace, which enables the Operator to watch and be made available to all namespaces in the cluster.
   2. Select Automatic for the Approval Strategy. This ensures that the future upgrades to the Operator are handled automatically by the Operator Lifecycle Manager (OLM). If you select the Manual approval strategy, OLM creates an update request. As a cluster administrator, you must then manually approve the OLM update request to update the Operator to the new version.

   3. Select an Update Channel.

      • By default, the stable channel enables installation of the latest stable and supported release of the Service Binding Operator.

5. Click Install.

   Note

   The Operator is installed automatically into the openshift-operators namespace.

6. On the Installed Operator — ready for use pane, click View Operator. You will see the Operator listed on the Installed Operators page.
7. Verify that the Status is set to Succeeded to confirm successful installation of Service Binding Operator.

Procedure

1. Create the PostgresCluster CR in the my-petclinic namespace by running the following command in shell:

   $ oc apply -n my-petclinic -f - << EOD
   ---
   apiVersion: postgres-operator.crunchydata.com/v1beta1
   kind: PostgresCluster
   metadata:
     name: hippo
   spec:
     image: registry.developers.crunchydata.com/crunchydata/crunchy-postgres-ha:centos8-13.4-0
     postgresVersion: 13
     instances:
       - name: instance1
         dataVolumeClaimSpec:
           accessModes:
           - "ReadWriteOnce"
           resources:
             requests:
               storage: 1Gi
     backups:
       pgbackrest:
         image: registry.developers.crunchydata.com/crunchydata/crunchy-pgbackrest:centos8-2.33-2
         repos:
         - name: repo1
           volume:
             volumeClaimSpec:
               accessModes:
               - "ReadWriteOnce"
               resources:
                 requests:
                   storage: 1Gi
         - name: repo2
           volume:
             volumeClaimSpec:
               accessModes:
               - "ReadWriteOnce"
               resources:
                 requests:
                   storage: 1Gi
     proxy:
       pgBouncer:
         image: registry.developers.crunchydata.com/crunchydata/crunchy-pgbouncer:centos8-1.15-2
   EOD

   The annotations added in this PostgresCluster CR enable the service binding connection and trigger the Operator reconciliation.

   The output verifies that the database instance is created:

   Example output

   postgrescluster.postgres-operator.crunchydata.com/hippo created

2. After you have created the database instance, ensure that all the pods in the my-petclinic namespace are running:

   $ oc get pods -n my-petclinic

   The output, which takes a few minutes to display, verifies that the database is created and configured:

   Example output

   NAME                               READY   STATUS    RESTARTS   AGE
   hippo-backup-nqjg-2rq94            1/1     Running   0          35s
   hippo-instance1-nw92-0             3/3     Running   0          112s
   hippo-pgbouncer-57b98f4476-znsk5   2/2     Running   0          112s
   hippo-repo-host-0                  1/1     Running   0          112s

   After the database is configured, you can deploy the sample application and connect it to the database service.

Procedure

1. Deploy the spring-petclinic application with the PostgresCluster custom resource (CR) by running the following command in shell:

   $ oc apply -n my-petclinic -f - << EOD
   ---
   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: spring-petclinic
     labels:
       app: spring-petclinic
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: spring-petclinic
     template:
       metadata:
         labels:
           app: spring-petclinic
       spec:
         containers:
           - name: app
             image: quay.io/service-binding/spring-petclinic:latest
             imagePullPolicy: Always
             env:
             - name: SPRING_PROFILES_ACTIVE
               value: postgres
             ports:
             - name: http
               containerPort: 8080
   ---
   apiVersion: v1
   kind: Service
   metadata:
     labels:
       app: spring-petclinic
     name: spring-petclinic
   spec:
     type: NodePort
     ports:
       - port: 80
         protocol: TCP
         targetPort: 8080
     selector:
       app: spring-petclinic
   EOD

   The output verifies that the Spring PetClinic sample application is created and deployed:

   Example output

   deployment.apps/spring-petclinic created
   service/spring-petclinic created

   Note

   If you are deploying the application using Container images in the Developer perspective of the web console, you must enter the following environment variables under the Deployment section of the Advanced options:

   • Name: SPRING_PROFILES_ACTIVE
   • Value: postgres

2. Verify that the application is not yet connected to the database service by running the following command:

   $ oc get pods -n my-petclinic

   The output takes a few minutes to display the CrashLoopBackOff status:

   Example output

   NAME                                READY   STATUS             RESTARTS      AGE
   spring-petclinic-5b4c7999d4-wzdtz   0/1     CrashLoopBackOff   4 (13s ago)   2m25s

   At this stage, the pod fails to start. If you try to interact with the application, it returns errors.

Procedure

1. Create a ServiceBinding CR to project the binding data:

   $ oc apply -n my-petclinic -f - << EOD
   ---
   apiVersion: binding.operators.coreos.com/v1alpha1
   kind: ServiceBinding
   metadata:
     name: spring-petclinic-pgcluster
   spec:
     services: 1
       - group: postgres-operator.crunchydata.com
         version: v1beta1
         kind: PostgresCluster 2
         name: hippo
     application: 3
       name: spring-petclinic
       group: apps
       version: v1
       resource: deployments
   EOD

   1

   Specifies a list of service resources.

   2

   The CR of the database.

   3

   The sample application that points to a Deployment or any other similar resource with an embedded PodSpec.

   The output verifies that the ServiceBinding CR is created to project the binding data into the sample application.

   Example output

   servicebinding.binding.operators.coreos.com/spring-petclinic created

2. Verify that the request for service binding is successful:

   $ oc get servicebindings -n my-petclinic

   Example output

   NAME                         READY   REASON              AGE
   spring-petclinic-pgcluster   True    ApplicationsBound   7s

   By default, the values from the binding data of the database service are projected as files into the workload container that runs the sample application. For example, all the values from the Secret resource are projected into the bindings/spring-petclinic-pgcluster directory.

   Note

   Optionally, you can also verify that the files in the application contain the projected binding data, by printing out the directory contents:

   $ for i in username password host port type; do oc exec -it deploy/spring-petclinic -n my-petclinic -- /bin/bash -c 'cd /tmp; find /bindings/*/'$i' -exec echo -n {}:" " \; -exec cat {} \;'; echo; done

   Example output: With all the values from the secret resource

   /bindings/spring-petclinic-pgcluster/username: <username>
   /bindings/spring-petclinic-pgcluster/password: <password>
   /bindings/spring-petclinic-pgcluster/host: hippo-primary.my-petclinic.svc
   /bindings/spring-petclinic-pgcluster/port: 5432
   /bindings/spring-petclinic-pgcluster/type: postgresql

3. Set up the port forwarding from the application port to access the sample application from your local environment:

   $ oc port-forward --address 0.0.0.0 svc/spring-petclinic 8080:80 -n my-petclinic

   Example output

   Forwarding from 0.0.0.0:8080 -> 8080
   Handling connection for 8080

4. Access http://localhost:8080/petclinic.

   You can now remotely access the Spring PetClinic sample application at localhost:8080 and see that the application is now connected to the database service.

Procedure

1. To deploy the Dev4Devs PostgreSQL Operator in the my-petclinic namespace run the following command in shell:

Verification

1. After the operator is installed, list the operator subscriptions in the openshift-operators namespace:

   $ oc get subs -n openshift-operators

   Example output

   NAME                               PACKAGE                            SOURCE                  CHANNEL
   postgresql-operator-dev4devs-com   postgresql-operator-dev4devs-com   ibm-multiarch-catalog   alpha
   rh-service-binding-operator        rh-service-binding-operator        redhat-operators        stable

Procedure

1. Create the Database CR in the my-petclinic namespace by running the following command in shell:

   $ oc apply -f - << EOD
   apiVersion: postgresql.dev4devs.com/v1alpha1
   kind: Database
   metadata:
     name: sampledatabase
     namespace: my-petclinic
     annotations:
       host: sampledatabase
       type: postgresql
       port: "5432"
       service.binding/database: 'path={.spec.databaseName}'
       service.binding/port: 'path={.metadata.annotations.port}'
       service.binding/password: 'path={.spec.databasePassword}'
       service.binding/username: 'path={.spec.databaseUser}'
       service.binding/type: 'path={.metadata.annotations.type}'
       service.binding/host: 'path={.metadata.annotations.host}'
   spec:
     databaseCpu: 30m
     databaseCpuLimit: 60m
     databaseMemoryLimit: 512Mi
     databaseMemoryRequest: 128Mi
     databaseName: "sampledb"
     databaseNameKeyEnvVar: POSTGRESQL_DATABASE
     databasePassword: "samplepwd"
     databasePasswordKeyEnvVar: POSTGRESQL_PASSWORD
     databaseStorageRequest: 1Gi
     databaseUser: "sampleuser"
     databaseUserKeyEnvVar: POSTGRESQL_USER
     image: registry.redhat.io/rhel8/postgresql-13:latest
     databaseStorageClassName: nfs-storage-provisioner
     size: 1
   EOD

   The annotations added in this Database CR enable the service binding connection and trigger the Operator reconciliation.

   The output verifies that the database instance is created:

   Example output

   database.postgresql.dev4devs.com/sampledatabase created

2. After you have created the database instance, ensure that all the pods in the my-petclinic namespace are running:

   $ oc get pods -n my-petclinic

   The output, which takes a few minutes to display, verifies that the database is created and configured:

   Example output

   NAME                                     READY    STATUS      RESTARTS   AGE
   sampledatabase-cbc655488-74kss            0/1     Running        0       32s

Procedure

1. Deploy the spring-petclinic application with the PostgresCluster custom resource (CR) by running the following command in shell:

   $ oc apply -n my-petclinic -f - << EOD
   ---
   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: spring-petclinic
     labels:
       app: spring-petclinic
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: spring-petclinic
     template:
       metadata:
         labels:
           app: spring-petclinic
       spec:
         containers:
           - name: app
             image: quay.io/service-binding/spring-petclinic:latest
             imagePullPolicy: Always
             env:
             - name: SPRING_PROFILES_ACTIVE
               value: postgres
             - name: org.springframework.cloud.bindings.boot.enable
               value: "true"
             ports:
             - name: http
               containerPort: 8080
   ---
   apiVersion: v1
   kind: Service
   metadata:
     labels:
       app: spring-petclinic
     name: spring-petclinic
   spec:
     type: NodePort
     ports:
       - port: 80
         protocol: TCP
         targetPort: 8080
     selector:
       app: spring-petclinic
   EOD

   The output verifies that the Spring PetClinic sample application is created and deployed:

   Example output

   deployment.apps/spring-petclinic created
   service/spring-petclinic created

   Note

   If you are deploying the application using Container images in the Developer perspective of the web console, you must enter the following environment variables under the Deployment section of the Advanced options:

   • Name: SPRING_PROFILES_ACTIVE
   • Value: postgres

2. Verify that the application is not yet connected to the database service by running the following command:

   $ oc get pods -n my-petclinic

   It takes take a few minutes until the CrashLoopBackOff status is displayed:

   Example output

   NAME                                READY   STATUS             RESTARTS      AGE
   spring-petclinic-5b4c7999d4-wzdtz   0/1     CrashLoopBackOff   4 (13s ago)   2m25s

   At this stage, the pod fails to start. If you try to interact with the application, it returns errors.

Procedure

1. Create a ServiceBinding CR to project the binding data:

   $ oc apply -n my-petclinic -f - << EOD
   ---
   apiVersion: binding.operators.coreos.com/v1alpha1
   kind: ServiceBinding
   metadata:
       name: spring-petclinic-pgcluster
   spec:
     services: 1
       - group: postgresql.dev4devs.com
         kind: Database 2
         name: sampledatabase
         version: v1alpha1
     application: 3
       name: spring-petclinic
       group: apps
       version: v1
       resource: deployments
   EOD

   1

   Specifies a list of service resources.

   2

   The CR of the database.

   3

   The sample application that points to a Deployment or any other similar resource with an embedded PodSpec.

   The output verifies that the ServiceBinding CR is created to project the binding data into the sample application.

   Example output

   servicebinding.binding.operators.coreos.com/spring-petclinic created

2. Verify that the request for service binding is successful:

   $ oc get servicebindings -n my-petclinic

   Example output

   NAME                          READY   REASON              AGE
   spring-petclinic-postgresql   True    ApplicationsBound   47m

   By default, the values from the binding data of the database service are projected as files into the workload container that runs the sample application. For example, all the values from the Secret resource are projected into the bindings/spring-petclinic-pgcluster directory.

3. Once this is created, you can go to the topology to see the visual connection.

   Figure 6.1. Connecting spring-petclinic to a sample database

   

4. Set up the port forwarding from the application port to access the sample application from your local environment:

   $ oc port-forward --address 0.0.0.0 svc/spring-petclinic 8080:80 -n my-petclinic

   Example output

   Forwarding from 0.0.0.0:8080 -> 8080
   Handling connection for 8080

5. Access http://localhost:8080.

   You can now remotely access the Spring PetClinic sample application at localhost:8080 and see that the application is now connected to the database service.

1. By default, as files.
2. As environment variables, after you configure the .spec.bindAsFiles parameter from the ServiceBinding resource.

Procedure

1. To project the binding data as files, determine the destination folder by ensuring that the existing SERVICE_BINDING_ROOT environment variable is present in the container where your workload runs.
2. To project the binding data as environment variables, set the value for the .spec.bindAsFiles parameter to false from the ServiceBinding resource in the custom resource (CR).

Procedure

1. Hover over the Spring PetClinic sample application to see a dangling arrow on the node.

   Figure 6.2. Visual connector

   
2. Click and drag the arrow towards the hippo-pgbouncer deployment to connect the Spring PetClinic sample application with it.
3. Click the spring-petclinic deployment to see the Overview panel. Under the Details tab, click the edit icon in the Annotations section to see the Key = app.openshift.io/connects-to and Value = [{"apiVersion":"apps/v1","kind":"Deployment","name":"hippo-pgbouncer"}] annotation added to the deployment.

Procedure

1. Switch to the Developer perspective and ensure that you are in the appropriate project, for example, my-petclinic. In the Topology view, hover over the Spring PetClinic sample application to see a dangling arrow on the node.

2. Click and drag the arrow towards the hippo database in the Postgres Cluster to make a binding connection with the Spring PetClinic sample application. A Create Service Binding dialog box appears.

   1. Enter the name and click Create.

      Figure 6.4. Service Binding modal