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Coherence Operator

The Oracle Coherence Operator is an open-source Kubernetes operator that enables the deployment and management of Oracle Coherence clusters in Kubernetes environments. It provides features to assist with deploying, scaling, and managing Coherence data grid clusters using cloud-native technologies. Full Documentation can be found here

note

Note that the Coherence Operator is deprecated in this release of OBaaS and may be removed in a future release.

Installing the Coherence Operator​

The cluster-wide Coherence Operator is installed by the obaas-prereqs chart. Install that chart once per cluster and keep coherence-operator.enabled set to true (the default). The operator runs in the namespace used for the obaas-prereqs release and must watch the namespace where an OBaaS release creates a Coherence cluster.

# obaas-prereqs values
coherence-operator:
  enabled: true

Before installing an OBaaS release with Coherence enabled, verify that the operator is ready and the Coherence custom resource definition is established:

kubectl rollout status deployment/coherence-operator -n <platform-system-namespace> --timeout=5m
kubectl wait --for=condition=Established crd/coherence.coherence.oracle.com --timeout=5m

Creating a Coherence Cluster​

Enable Coherence in the namespace-scoped obaas chart. The provided values-coherence.yaml example creates a three-member, ephemeral cluster named mysample-cluster, with a 512 MiB JVM heap and an HTTP port on 8080. Set coherence.name to a DNS-compatible name unique within the release namespace. The cluster uses the default Coherence image configured by the installed operator unless you override coherence.image.

helm upgrade --install <app-release> obaas/obaas \
  -f examples/values-coherence.yaml \
  -n <application-namespace> \
  --create-namespace

Helm creates the Coherence custom resource using coherence.name in the OBaaS release namespace. Verify <coherence-cluster-name> and wait for all three members:

kubectl get coherence <coherence-cluster-name> -n <application-namespace>
kubectl wait -n <application-namespace> \
  --for=jsonpath='{.status.readyReplicas}'=3 \
  coherence/<coherence-cluster-name> \
  --timeout=5m
kubectl get pods -n <application-namespace>

The Coherence Operator creates and manages an internal health port on 6676 for the cluster members. It configures the Kubernetes liveness probe as GET /healthz and the readiness probe as GET /ready. This port is intentionally not added to coherence.ports or exposed through the application Service.

To create durable Coherence data, layer an override with persistence settings after values-coherence.yaml. Choose a StorageClass and size appropriate to the cluster:

coherence:
  coherence:
    persistence:
      mode: active
      persistentVolumeClaim:
        storageClassName: <storage-class>
        accessModes:
          - ReadWriteOnce
        resources:
          requests:
            storage: 10Gi

The Coherence custom resource is owned by the OBaaS Helm release. Do not create a second resource with the same name outside Helm.

Manually managed cluster (advanced)​

For a Coherence cluster that is intentionally independent of an OBaaS Helm release, create its custom resource directly after installing and verifying the operator. Use a namespace of your choice and manage its lifecycle separately from Helm.

apiVersion: coherence.oracle.com/v1
kind: Coherence
metadata:
  name: mysample-cluster
spec:
  replicas: 3
  jvm:
    memory:
      heapSize: 512m
  ports:
    - name: http
      port: 8080
kubectl apply -f mysample-cluster.yaml -n coherence
kubectl describe coherence mysample-cluster -n coherence
kubectl get pods -n coherence

Using Coherence with Spring Boot​

To connect your Spring Boot application to a Coherence cluster, add the following dependencies and configuration. Set the client cluster name to the value configured in coherence.name; the Helm example uses mysample-cluster. Coherence Spring Documentation

Dependencies​

Maven (pom.xml):

<dependencies>
    <!-- Coherence Spring Boot Starter -->
    <dependency>
        <groupId>com.oracle.coherence.spring</groupId>
        <artifactId>coherence-spring-boot-starter</artifactId>
    </dependency>

    <!-- Coherence CE -->
    <dependency>
        <groupId>com.oracle.coherence.ce</groupId>
        <artifactId>coherence</artifactId>
    </dependency>
</dependencies>

Spring Boot Configuration​

Create or update your application.yaml file to connect to the Helm-managed cluster. Replace mysample-cluster with your chosen cluster name:

coherence:
  # Set the instance type to 'client' to connect to an existing cluster
  instance:
    type: client

  # Configure the cluster connection
  cluster:
    name: mysample-cluster

  # Configure sessions
  sessions:
    - name: default
      config: coherence-cache-config.xml
      priority: 1

  # Logging configuration (optional)
  logging:
    destination: slf4j
    logger-name: Coherence

  # Server startup timeout (optional)
  server:
    startup-timeout: 60s