Getting started with service binding on IBM Power, IBM Z, and IBM® LinuxONE
The Service Binding Operator manages the data plane for workloads and backing services. This guide provides instructions with examples to help you create a database instance, deploy an application, and use the Service Binding Operator to create a binding connection between the application and the database service.
Prerequisites
You have access to an OKD cluster using an account with
cluster-admin
permissions.You have installed the
oc
CLI.You have installed the Service Binding Operator from OperatorHub.
Deploying a PostgreSQL Operator
Procedure
- To deploy the Dev4Devs PostgreSQL Operator in the
my-petclinic
namespace run the following command in shell:
$ oc apply -f - << EOD
---
apiVersion: v1
kind: Namespace
metadata:
name: my-petclinic
---
apiVersion: operators.coreos.com/v1
kind: OperatorGroup
metadata:
name: postgres-operator-group
namespace: my-petclinic
---
apiVersion: operators.coreos.com/v1alpha1
kind: CatalogSource
metadata:
name: ibm-multiarch-catalog
namespace: openshift-marketplace
spec:
sourceType: grpc
image: quay.io/ibm/operator-registry-<architecture> (1)
imagePullPolicy: IfNotPresent
displayName: ibm-multiarch-catalog
updateStrategy:
registryPoll:
interval: 30m
---
apiVersion: operators.coreos.com/v1alpha1
kind: Subscription
metadata:
name: postgresql-operator-dev4devs-com
namespace: openshift-operators
spec:
channel: alpha
installPlanApproval: Automatic
name: postgresql-operator-dev4devs-com
source: ibm-multiarch-catalog
sourceNamespace: openshift-marketplace
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: database-view
labels:
servicebinding.io/controller: "true"
rules:
- apiGroups:
- postgresql.dev4devs.com
resources:
- databases
verbs:
- get
- list
EOD
1 | The Operator image.
|
Verification
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
Creating a PostgreSQL database instance
To create a PostgreSQL database instance, you must create a Database
custom resource (CR) and configure the database.
Procedure
Create the
Database
CR in themy-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
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
After the database is configured, you can deploy the sample application and connect it to the database service.
Deploying the Spring PetClinic sample application
To deploy the Spring PetClinic sample application on an OKD cluster, you must use a deployment configuration and configure your local environment to be able to test the application.
Procedure
Deploy the
spring-petclinic
application with thePostgresCluster
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
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
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.
You can now use the Service Binding Operator to connect the application to the database service.
Connecting the Spring PetClinic sample application to the PostgreSQL database service
To connect the sample application to the database service, you must create a ServiceBinding
custom resource (CR) that triggers the Service Binding Operator to project the binding data into the application.
Procedure
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
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.Once this is created, you can go to the topology to see the visual connection.
Figure 1. Connecting spring-petclinic to a sample database
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
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.