coherence-operator

Storage-Disabled Client in Cluster as Separate User Image

To ensure that a custom made container and Helm Chart can be installed and joins an existing Coherence cluster, perform the following steps for the custom container:

• Ensure that the correct version of Coherence is included in the package.

• Set Cluster Name to match the name of the Coherence cluster you are running.

• Set Well Known Address to match the headless service name of the Coherence cluster you are running.

• Disable local storage using the setting, -Dcoherence.distributed.localstorage=false

This sample shows how a Helidon web application exposes a /query endpoint, allowing CohQL commands to be passed and executed against a Coherence cluster.

Return to Storage-Disabled clients samples / Return to Coherence Deployments samples / Return to samples

Sample files

• src/assembly/helm-assembly.xml - Assembly file for Helm

• src/main/java/com/oracle/coherence/examples/Main.java - Entry point for Helidon web application

• src/main/helm/ - Helm chart files

Note: If you want to enable Prometheus or log capture, ensure you set the appropriate properties for the Coherence Operator install:

• Prometheus: --set prometheusoperator.enabled=true

• Log capture: --set logCaptureEnabled=true

Prerequisites

Ensure that you have installed the Coherence Operator by following the instructions here.

Installation Steps

1. Change to the samples/coherence-deployments/storage-disabled/other directory. Ensure that you have your maven build environment set for JDK8, and build the project.

   $ mvn clean install -P docker
   

   This builds the Docker image with the cache configuration files, with the name in the format, helidon-sample:${version}. This image is subsequently used by the chart.

   Note: If you are running against a remote Kubernetes cluster, you must push the above image to your repository accessible to that cluster. You must also prefix the image name in the helm command, as shown below.

2. Install the Coherence cluster.

   $ helm install \
      --namespace sample-coherence-ns \
      --name storage \
      --set clusterSize=3 \
      --set cluster=helidon-cluster \
      --set imagePullSecrets=sample-coherence-secret \
      --set logCaptureEnabled=false \
      coherence/coherence
   

   After the installation is complete, get the list of pods by running the following command:

   $ kubectl get pods -n sample-coherence-ns
   

   All the three storage-coherence pods should be running and ready, as shown in the output:

   NAME                    READY   STATUS    RESTARTS   AGE
   storage-coherence-0     1/1     Running   0          4m
   storage-coherence-1     1/1     Running   0          2m   
   storage-coherence-2     1/1     Running   0          2m
   

3. Install the Helidon web application.

   When you install the Helidon web application, ensure that you set the following properties to allow the Helidon application to join the Coherence cluster:

   • --set cluster=helidon-cluster - Uses the same cluster name

   • --set store.wka=storage-coherence-headless - Ensures that it can contact the cluster

   $ helm install \
      --namespace sample-coherence-ns \
      --set wka=storage-coherence-headless \
      --set clusterName=helidon-cluster \
      --name helidon-web-app \
      target/webserver-1.0.0-SNAPSHOT-helm/webserver/
   

   As per the instructions output above, port forward port 8080.

   $ export POD_NAME=$(kubectl get pods --namespace sample-coherence-ns -l "app=webserver,release=helidon-web-app" -o jsonpath="{.items[0].metadata.name}")
   $ kubectl --namespace sample-coherence-ns port-forward $POD_NAME 8080:8080
   Forwarding from 127.0.0.1:8080 -> 8080
   Forwarding from [::1]:8080 -> 8080
   

4. Run CohQL commands.

   Use the various CohQL commands to create and mutate data in the Coherence cluster.

   $ curl -i -w '\n' -X PUT http://127.0.0.1:8080/query -d '{"query":"create cache foo"}'
   
   HTTP/1.1 200 OK
   Date: Thu, 18 Apr 2019 06:48:15 GMT
   transfer-encoding: chunked
   connection: keep-alive
   
   $ curl -i -w '\n' -X PUT http://127.0.0.1:8080/query -d '{"query":"insert into foo key(\"foo\") value(\"bar\")"}'
   
   HTTP/1.1 200 OK
   Date: Thu, 18 Apr 2019 06:48:40 GMT
   transfer-encoding: chunked
   connection: keep-alive
   
   $ curl -i -w '\n' -X PUT http://127.0.0.1:8080/query -d '{"query":"select key(),value() from foo"}'
   HTTP/1.1 200 OK
   Content-Type: application/json
   Date: Thu, 18 Apr 2019 06:49:15 GMT
   transfer-encoding: chunked
   connection: keep-alive
   
   {"result":"{foo=[foo, bar]}"}
   

Uninstall the Charts

Run the following command to delete both the charts installed in this sample.

$ helm delete storage helidon-web-app --purge

Before starting another sample, ensure that all pods are removed from the previous sample. To remove coherence-operator, use the helm delete command.

This site is open source. Improve this page.