Oracle Coherence Demonstration Application

Overview

This document describes how to build and run the Coherence Demonstration application. The application showcases Coherence general features, scalability capabilities including:

• Clustering and Data Sharding
• Scalability and High Availability
• Disk-Based Persistence
• Parallel Queries
• Efficient Aggregation
• In-Place Processing
• Federation (Grid Edition feature only)
• Lambda Support
• OpenTracing Support
• Polyglot client access from JavaScript, Python and Golang
• Listening for events using Server Sent Events (SSE)

You can run the application locally using mvn exec:exec or run on Kubernetes using the Coherence Operator. See the table of contents below for instructions.

The demonstration uses AngularJS 1.7.5, Bootstrap 3.3.4, and a number of other frameworks. The UI interacts with Coherence using the REST API.

Note: By default, this demonstration uses the Coherence Community Edition version 24.09 and as a consequence the commercial-only feature "Federation" is not available by default.

Please see here if you wish to enable Federation by running using Coherence Grid Edition.

This version has been updated to move from javax -> jakarta packages and as such if you wish to run this demo against a previous CE or Grid Edition version, you must use git checkout v5.0.1 to checkout a release of the demo that works with this version.

Table of Contents

• Oracle Coherence Demonstration Application
  • Overview
  • Table of Contents
  • Prerequisites
    • General Prerequisites
    • OpenTracing Prerequisites
  • Run the Application Locally
    • Modify the Defaults
  • Run the Polyglot clients
  • Run the Application on Kubernetes
  • Enable Federation on Kubernetes (Grid Edition Only)
  • Run the Demonstration using Coherence Grid Edition
  • View Cluster Metrics via Grafana
  • References

Prerequisites

General Prerequisites

To run the demonstration application, you must have the following software installed:

1. Java 21 SE Development Kit or Runtime environment.

   You can download JDK 21 from Java SE Development Kit Downloads

2. Maven 3.6.0 or later version installed and configured.

3. Use a web browser that supports AngularJS to run the application. The following browsers are supported:

   • Safari, Chrome, Firefox, Opera 15, IE9 and mobile browsers (Android, Chrome Mobile, iOS Safari).

   For more information about browser compatibility, see https://code.angularjs.org/1.7.5/docs/misc/faq.

OpenTracing Prerequisites

If you wish to demonstrate OpenTracing, then prior to running the demo, start the Jaeger OpenTracing implementation:

docker run --rm -d --name jaeger \
        -e COLLECTOR_ZIPKIN_HTTP_PORT=9411 \
        -p 5775:5775/udp \
        -p 6831:6831/udp \
        -p 6832:6832/udp \
        -p 5778:5778 \
        -p 16686:16686 \
        -p 14268:14268 \
        -p 9411:9411 \
        jaegertracing/all-in-one:1.20

Navigate to http://localhost:16686 in order to access the Jaeger UI.

Note: If Jaeger is already running in your environment locally, you can skip this step. If Jaeger is available at a different location, specify the JAEGER_ENDPOINT JVM property when starting the demo to override the default location.

The following screenshot shows the Jaegar UI and a trace from a JAX-RS call to Coherence to JPA cache store, then backing up of cache entries across to another node.

Run the Application Locally

Build the application using Maven:

mvn clean install

The target directory contains a list of files:

coherence-demo-{version}-SNAPSHOT-javadoc.jar - javadoc
coherence-demo-{version}-SNAPSHOT-sources.jar - sources

Run demo application

mvn exec:exec

Note: If you wish to run against an older Coherence CE version than 22.09 or older than Coherence GE 14.1.1.2206.1, then must first use git checkout v5.0.1 to use the current 5.0.1 release that supports these older versions.

The following screenshot shows the application running with 5 cache servers started.

A Coherence Cache server and HTTP server are started on port 8080 for serving application data. When the Cache server starts, the application loads on the default web browser at http://127.0.0.1:8080/application/index.html.

The following features are available to demonstrate in the application:

• Dynamically add or remove cluster members and observe the data repartition and recover automatically.
• Create and recover snapshots from the Persistence menu.
• Enable real-time price updates.
• Enable or disable indexes for queries.
• Add additional data, clear the cache or populate the cache from the Tools menu.
• Show OpenTracing Support
• Open raw metrics endpoint

Federation Features - Grid Edition Only

• Start a secondary cluster from the Federation menu.
• Pause and resume replication to secondary cluster.
• Issue replicate all to secondary cluster.
• Open secondary cluster dashboard to observe changes are replicated.
• Stop Federation and shut down secondary cluster.

Note: If you wish to connect to the cluster via the VisualVM Plugin, see https://github.com/oracle/coherence-visualvm.

Note: If you recover a snapshot on a cluster, you must replicate all to resynchronize.

To shut down the application, select Shutdown option from the Tools menu. This shuts down all the processes including the secondary cluster if started.

Note: Secondary cluster will not form if you are running on a virtual private network due to security restrictions.

You can use the following to run the application with the Metrics endpoint enabled:

mvn -Dmetrics.enabled=true exec:exec

From the Tools menu choose Show Raw Metrics to view the raw metrics.

Modify the Defaults

HTTP Ports and Hostname

The default HTTP hostname is 127.0.0.1 and default port is 8080. To modify these you can add the http.hostname or http.port properties on startup:

mvn -Dhttp.hostname=myhostname -Dhttp.port=9000 exec:exec

By changing the http.hostname you can access the application outside of your local machine.

Run the Application on Kubernetes

The steps to run the application on Kubernetes comprises:

• Use kubectl to install the Oracle Coherence Operator
• Use kubectl to install the Coherence cluster which comprises 2 roles:
  • storage-enabled Coherence servers
  • storage-disabled application with Grizzly HTTP Server

Note: If you want to enable Federation when running on Kubernetes, see Enable Federation on Kubernetes.

1. Create Namespace

   Run the application using the Oracle Coherence Operator in a namespace called coherence-example. Create the demonstration namespace:

   kubectl create namespace coherence-example
   
   namespace/coherence-example created

2. Build and Push Docker Image

   Ensure that you have Docker running locally and execute the following command which will used the jib-maven-plugin to build a Docker image.

   mvn clean install -P docker

   This creates an image named coherence-demo:8.1.0-SNAPSHOT which contains everything needed to run the demo.

   Note: If you are running against a remote Kubernetes cluster, you need to push the Docker image to your repository accessible to that cluster. You also need to prefix the image name in the yaml files used in the helm commands below. Find your Docker image id with docker images and tag it with your prefix: docker tag image youname/coherence-demo:8.1.0-SNAPSHOT and them push using docker push youname/coherence-demo:8.1.0-SNAPSHOT.

3. Install the Oracle Coherence Operator

   You must have a supported version of Kubernetes. Please see https://github.com/oracle/coherence-operator for more details.

   Install the operator using kubectl. (It will be installed into a new namespace called coherence)

   kubectl apply -f https://github.com/oracle/coherence-operator/releases/download/v3.3.3/coherence-operator.yaml

   Confirm the creation of the operator:

    kubectl get pods -n coherence
    NAME                                                     READY   STATUS    RESTARTS      AGE
    coherence-operator-controller-manager-55fd645db8-9tnvq   1/1     Running   1 (11m ago)   12m
    coherence-operator-controller-manager-55fd645db8-bk46q   1/1     Running   1 (11m ago)   12m
    coherence-operator-controller-manager-55fd645db8-rlfv8   1/1     Running   0             12m

4. Install the Coherence Cluster

   The Coherence cluster comprises 2 roles:

   • storage - contains the storage-enabled tier which stores application data
   • http - contains a storage-disabled http server which serves the application

   The file demo-cluster.yaml contains the yaml to install the two Coherence cluster roles.

   Issue the following command to install the Coherence cluster using the above yaml:

   kubectl create --namespace coherence-example -f yaml/demo-cluster.yaml

   Use kubectl get pods --namespace coherence-example to ensure that the pod is running. The pod primary-cluster-storage-0 must be running and ready as shown:

    kubectl get pods -n coherence-example
    NAME                        READY   STATUS    RESTARTS   AGE
    primary-cluster-http-0      1/1     Running   0          5s
    primary-cluster-storage-0   1/1     Running   0          5s
    primary-cluster-storage-1   1/1     Running   0          5s

   If the pod does not show as Running, you can use the following command to diagnose and troubleshoot the pod:

   kubectl describe pod primary-cluster-storage-0 --namespace coherence-example

5. Port Forward the HTTP Port

   kubectl port-forward --namespace coherence-example primary-cluster-http-0 8080:8080

6. Access the Application
   

   Use the following URL to access the application home page:

   http://127.0.0.1:8080/application/index.html

7. Scale the Application

   When running the application in Kubernetes, the Add Server and Remove Server options are not available. You need to use kubectl to scale the application.

   Scale the application to three nodes by editing demo-cluster.yaml and changing the replicas value for the storage role to 3. Then apply using

   kubectl apply --namespace coherence-example -f yaml/demo-cluster.yaml

   You can also use the following to scale the cluster:

   kubectl scale --namespace coherence-example coherence/primary-cluster-storage --replicas=6

   Use kubectl --namespace coherence-example rollout status sts/primary-cluster-storage to view the progress.

8. Scale the Application down

   Scale the application to one node by editing demo-cluster.yaml and changing the replicas value for the storage role to 1. Then apply using

   kubectl apply --namespace coherence-example -f yaml/demo-cluster.yaml

   Use kubectl -n coherence-example rollout status sts/primary-cluster-storage to view the progress.

   Note: The Coherence Operator ensures that all scale operations are carried out in a safe manner (checking service statusHA values) to ensure no data is lost. You can confirm this by checking the number of positions are the same as before the scale-down was initiated.

9. Uninstall the Coherence Cluster

   Use the following to uninstall the Coherence cluster.

   kubectl delete --namespace coherence-example -f yaml/demo-cluster.yaml    

Enable Federation on Kubernetes (Grid Edition Only)

You must use Oracle Coherence 12.2.1.4.0 or later for Federation to work within Kubernetes.

The setup for this example uses two Coherence clusters in the same Kubernetes cluster. If you want to use Federation across Kubernetes cluster, see the Oracle Coherence Operator Samples.

• Primary Cluster
  • Cluster name: primary-cluster
• Secondary Cluster
  • Cluster name: secondary-cluster

Note: For this Federation example, the installation is simplified by using the storage-enabled pods to also serve the HTTP requests.

1. Create Namespace

   Run the application using the Oracle Coherence Operator in a namespace called coherence-example. Create the demonstration namespace:

   kubectl create namespace coherence-example
   
   namespace/coherence-example created

2. Build the Docker image:

   git checkout v5.0.1 # required for pre CE 22.09 versions
   mvn clean install -P docker,grid-edition -Dcoherence.version={coherence.version}

   Note: The coherence.version property must be set to your installed Coherence Grid Edition version.

3. Install the Primary cluster:

   The file primary-cluster.yaml contains the yaml to install the primary-cluster Coherence cluster.

   Issue the following command to install the Coherence cluster using the above yaml:

   kubectl create --namespace coherence-example -f yaml/primary-cluster.yaml

   Use kubectl get pods --namespace coherence-example to ensure that the pods are running.

   NAME                                 READY   STATUS    RESTARTS   AGE
   coherence-operator-cd9b646d5-tzf2j   1/1     Running   0          58m
   primary-cluster-http-0               1/1     Running   0          74s
   primary-cluster-storage-0            1/1     Running   0          76s

4. Port forward the Primary Cluster - Port 8088

   kubectl port-forward --namespace coherence-example primary-cluster-http-0 8080:8080

   Note: You may wish to run the above command in a separate terminal as it will block to process the HTTP requests.

   Use the following URL to access the application home page:

   http://127.0.0.1:8080/application/index.html

5. Install the Secondary cluster

   The file secondary-cluster.yaml contains the yaml to install the secondary-cluster Coherence cluster.

   Issue the following command to install the Coherence cluster using the above yaml:

   kubectl create --namespace coherence-example -f yaml/secondary-cluster.yaml

   Use kubectl get pods --namespace coherence-example to ensure that the pods are running.

   NAME                                 READY   STATUS    RESTARTS   AGE
   coherence-operator-cd9b646d5-tzf2j   1/1     Running   0          78m
   primary-cluster-http-0               1/1     Running   0          2m
   primary-cluster-storage-0            1/1     Running   0          2m
   primary-cluster-storage-1            1/1     Running   0          2ms
   secondary-cluster-http-0             1/1     Running   0          70s
   secondary-cluster-storage-0          1/1     Running   0          72s
   secondary-cluster-storage-1          1/1     Running   0          72s

6. Port forward the Secondary Cluster - Port 8090

   kubectl port-forward --namespace coherence-example secondary-cluster-http-0 8090:8080

   Use the following URL to access the application home page:

   http://127.0.0.1:8090/application/index.html

   You can see that there is no data in the Secondary cluster as the Federation is not yet started.

7. Start Federation on the Primary Cluster

   In the Primary Cluster, select Start Federation from Federation menu. Access the Secondary Cluster dashboard and you can see the data appearing from the Primary Cluster.

8. Uninstall the Coherence Clusters

   kubectl delete --namespace coherence-example -f yaml/primary-cluster.yaml    
   
   kubectl delete --namespace coherence-example -f yaml/secondary-cluster.yaml   

Before starting another sample, ensure that all the pods are removed from the previous sample.

Uninstalling the Coherence Operator

To remove the coherence-operator, the use the following:

 helm delete coherence-operator --namespace coherence-example

For helm version 2.X:

helm delete coherence-operator --purge

Run the Demonstration using Coherence Grid Edition

If you wish to demonstrate the Federation feature, which is only available in Coherence Grid Edition, you must carry out the following steps.

Download Oracle Coherence 14.1.1.0.0 or later.

You can download Coherence from http://www.oracle.com/technetwork/middleware/coherence/downloads/index.html.

If you want to demonstrate the Coherence VisualVM plug-in, follow the instructions to install: https://docs.oracle.com/en/middleware/standalone/coherence/14.1.1.0/manage/using-jmx-manage-oracle-coherence.html

Set the Environment Variables

Ensure that the following environment variables are set in your configuration:

• JAVA_HOME -- This variable must point to the location of the JDK version supported by the Oracle Coherence version that you use. Ensure that the path is set accordingly:
  For Linux/UNIX OS:

export PATH=$JAVA_HOME/bin:$PATH

For Windows OS:

set PATH=%JAVA_HOME%\bin;%PATH%

• COHERENCE_HOME -- This variable must point to the \coherence directory of your Coherence installation. This is required for the Maven install-file commands.

• MAVEN_HOME -- If mvn command is not set in your PATH variable, then set MAVEN_HOME directed to the bin folder of Maven installation and then add MAVEN_HOME\bin to your PATH variable list.

Install Coherence JARs into your Maven repository

Install Coherence and Coherence HTTP Netty installed into your local maven repository.

For Linux/UNIX/Mac OS:

mvn install:install-file -Dfile=$COHERENCE_HOME/lib/coherence.jar -DpomFile=$COHERENCE_HOME/plugins/maven/com/oracle/coherence/coherence/14.1.1/coherence.14.1.1.pom
mvn install:install-file -Dfile=$COHERENCE_HOME/lib/coherence-http-netty.jar -DpomFile=$COHERENCE_HOME/plugins/maven/com/oracle/coherence/coherence-http-netty/14.1.1/coherence-http-netty.14.1.1.pom

For Windows OS:

mvn install:install-file -Dfile=%COHERENCE_HOME%\lib\coherence.jar -DpomFile=%COHERENCE_HOME%\plugins\maven\com\oracle\coherence\coherence\14.1.1\coherence.14.1.1.pom
mvn install:install-file -Dfile=%COHERENCE_HOME%\lib\coherence-http-netty.jar -DpomFile=%COHERENCE_HOME%\plugins\maven\com\oracle\coherence\coherence-http-netty\14.1.1\coherence-http-netty.14.1.1.pom

Build using the grid-edition profile

When you issue any maven commands, ensure you include the grid-edition profile as below:

git checkout v5.0.1 # required for pre CE 22.09 versions
mvn clean install -P grid-edition -Dcoherence.version=14.1.1-0-0

Note: The coherence.version property must be set to your installed Coherence Grid Edition version.

Run the application using:

mvn exec:exec -Pgrid-edition -Dcoherence.version=14.1.1-0-0

View Cluster Metrics via Grafana

If you wish to view metrics via Grafana, please carry out the steps here before you install any of the examples above.

Note: Before you run the above, you must change the namespace in src/main/yaml/prometheus-rbac.yaml in the coherence-operator cloned repository from coherence-example to coherence-example.

The following screenshot shows the application running within Oracle's Cloud Infrastructure (OCI) under Kubernetes.

References

For more information about Oracle Coherence, see the following links:

• Download Coherence - http://www.oracle.com/technetwork/middleware/coherence/downloads/index.html
• Coherence Documentation - https://docs.oracle.com/en/middleware/fusion-middleware/coherence/14.1.1.0/index.html
• Coherence Community - https://coherence.community/
• Coherence CE - https://github.com/oracle/coherence