Kubernetes Discovery for ActiveMQ

Building

Clone the repository and build the discovery agent using Maven:

mvn clean package

Once complete, copy the target/activemq-k8s-discovery-*-jar-with-dependencies.jar into the class-path of your ActiveMQ install.

Configuring

Here's an example snippet that can be added to your activemq.xml:

<networkConnector uri="k8s://default?podLabelKey=app&amp;podLabelValue=activemq"
            dynamicOnly="true"
            networkTTL="3"
            prefetchSize="1"
            decreaseNetworkConsumerPriority="true" />
</networkConnectors>

Here are the available options, these can be set using query parameters in the URI above:

Option	Default Value	Description
namespace	default	Kubernetes namespace
podLabelKey	app	Pod label key to match
podLabelValue	activemq	Pod label value to match
serviceUrlFormat	tcp://%s:61616	URL used, %s is replaced with the pod's IP
sleepDelay	30000	Delay in milliseconds between polls

Deploying

Here are some notes I used for testing the solution. I used to the Docker image from https://github.com/j-white/activemq.

Fire up a Kubernetes cluster and configure the local Docker environment to use the cluster:

minikube start --cpus=4 --memory=6000
eval $(minikube docker-env)

Now build the Docker image:

docker build -t cloud-activemq:1.0.0 .

Create the deployment and service:

kubectl create -f activemq-deployment.yaml --record
kubectl create -f activemq-service.yaml --record
kubectl get deployments
kubectl get services

Determine the IP address and port of the exposed service:

minikube ip
kubectl describe service activemq | grep NodePort

Peek at the logs:

kubectl exec activemq-deployment-1647995871-8q3vf -- tail -f /var/log/supervisor/activemq.log

Access the ActiveMQ Web UI:

kubectl port-forward activemq-deployment-1647995871-8q3vf 8161:8161

Scale up:

kubectl scale --replicas=6 deployment/activemq-deployment

Upgrade the deployment:

kubectl set image deployment/activemq-deployment activemq=cloud-activemq:1.0.1
kubectl rollout status deployment/activemq-deployment
kubectl get deployments