coherence-operator

Within a Single Kubernetes Cluster

The Federated Caching feature federates cached data asynchronously across multiple geographically dispersed clusters. Cached data is federated across clusters to provide redundancy, off-site backup, and multiple points of access for application users in different geographical locations.

This sample shows how to set up two Federated Coherence clusters within a single Kubernetes cluster.

Although this is not a recommended topology, due to the co-location of the Coherence clusters, this is included as a sample for how to use Federation.

Note: To set up two Federated Coherence clusters across different Kubernetes clusters, refer to the additional information here.

The setup for this example uses two Coherence clusters in the same Kubernetes cluster, with the following details:

Primary Cluster
- Release name: cluster-1
- Cluster name: PrimaryCluster
Secondary Cluster
- Release name: cluster-2
- Cluster name: SecondaryCluster

Return to Federation samples / Return to Coherence Deployments samples / Return to samples

Sample files

src/main/docker/Dockerfile - Dockerfile for creating sidecar image from which the configuration will be read at pod startup
src/main/resources/client-cache-config.xml - Cache configuration for the extend client
src/main/resources/conf/cache-config-federation.xml - Cache configuration for Federation
src/main/resources/conf/tangosol-coherence-override-federation.xml - Override for Federation

Prerequisites

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

Installation Steps

Change to the samples/coherence-deployments/federation/within-cluster directory. Ensure 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, proxy-tier-sample:${version}. For example,

   federation-within-cluster-sample:1.0.0-SNAPSHOT

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.

Install the primary Coherence cluster, PrimaryCluster.

$ helm install \
   --namespace sample-coherence-ns \
   --name cluster-1 \
   --set clusterSize=2 \
   --set cluster=PrimaryCluster \
   --set imagePullSecrets=sample-coherence-secret \
   --set store.cacheConfig=cache-config-federation.xml \
   --set store.overrideConfig=tangosol-coherence-override-federation.xml \
   --set store.javaOpts="-Dprimary.cluster=PrimaryCluster -Dprimary.cluster.port=40000 -Dprimary.cluster.host=cluster-1-coherence-headless -Dsecondary.cluster=SecondaryCluster -Dsecondary.cluster.port=40000 -Dsecondary.cluster.host=cluster-2-coherence-headless"  \
   --set store.ports.federation=40000 \
   --set userArtifacts.image=federation-within-cluster-sample:1.0.0-SNAPSHOT \
   --set coherence.image=your-12.2.1.4.0-Coherence-image \
   coherence/coherence

Note: Ensure that you replace your-12.2.1.4.0-Coherence-image with the appropriate Coherence 12.2.1.4.0 Docker image.

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

$ kubectl get pods -n sample-coherence-ns

Both the cluster-1-coherence pods should be running and ready, as shown in the output:

NAME                                  READY   STATUS    RESTARTS   AGE
cluster-1-coherence-0                 1/1     Running   0          24s
cluster-1-coherence-1                 1/1     Running   0          24s
coherence-operator-695b9456d5-bzbhl   1/1     Running   0          30m

Port Forward the PrimaryCluster Coherence*Extend - Port 20000.

$ kubectl port-forward --namespace sample-coherence-ns cluster-1-coherence-0  20000:20000

Install the secondary Coherence cluster, SecondaryCluster.

$ helm install \
   --namespace sample-coherence-ns \
   --name cluster-2 \
   --set clusterSize=2 \
   --set cluster=SecondaryCluster \
   --set imagePullSecrets=sample-coherence-secret \
   --set store.cacheConfig=cache-config-federation.xml \
   --set store.overrideConfig=tangosol-coherence-override-federation.xml \
   --set store.javaOpts="-Dprimary.cluster=PrimaryCluster -Dprimary.cluster.port=40000 -Dprimary.cluster.host=cluster-1-coherence-headless -Dsecondary.cluster=SecondaryCluster -Dsecondary.cluster.port=40000 -Dsecondary.cluster.host=cluster-2-coherence-headless"  \
   --set store.ports.federation=40000 \
   --set userArtifacts.image=federation-within-cluster-sample:1.0.0-SNAPSHOT \
   --set coherence.image=your-12.2.1.4.0-Coherence-image \
   coherence/coherence

After the installation has completed, get the list of pods by running the following command:

$ kubectl get pods -n sample-coherence-ns

All the four cluster-1 and cluster-2 pods should be running and ready, as shown in the output:

NAME                                  READY   STATUS    RESTARTS   AGE
cluster-1-coherence-0                 1/1     Running   0          4m
cluster-1-coherence-1                 1/1     Running   0          4m
cluster-2-coherence-0                 1/1     Running   0          36s
cluster-2-coherence-1                 1/1     Running   0          36s
coherence-operator-695b9456d5-bzbhl   1/1     Running   0          34m

Port Forward the SecondaryCluster Coherence*Extend - Port 20001.

$ kubectl port-forward --namespace sample-coherence-ns cluster-2-coherence-0  20001:20000

Use CohQL to connect to each cluster.

Run CohQL against the PrimaryCluster by using the following command:
```
$ mvn exec:java -Dproxy.port=20000
```
Open another terminal and run CohQL against the SecondaryCluster:
```
$ mvn exec:java -Dproxy.port=20001
```

Insert data into the PrimaryCluster.

Run the following CohQL command to insert data into the PrimaryCluster:

insert into 'test' key('key-1') value('value-1');

select key(), value() from 'test';
Results
["key-1", "value-1"]

select count() from 'test';
Results
1

Confirm that the data has been federated to the SecondaryCluster.

Run the following CohQL command to insert data into the SecondaryCluster:
```
select key(), value() from 'test';
Results
["key-1", "value-1"]
```

Insert data into the SecondaryCluster

Run the following CohQL command to insert data into the SecondaryCluster:

insert into 'test' key('key-2') value('value-2');

select key(), value() from 'test';
Results
["key-1", "value-1"]
["key-2", "value-2"]

Confirm that the data has been federated to the PrimaryCluster.

Run the following CohQL command to insert data into the PrimaryCluster:

   select key(), value() from 'test';
   Results
   ["key-1", "value-1"]
   ["key-2", "value-2"]

Uninstall the Charts

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

$ helm delete cluster-1 cluster-2 --purge

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

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