Artemis k8s cluster client connection handling

Question

I am using the Artemis Cloud operator for deploying ActiveMQ Artemis in k8s cluster. Number of replicas configured is 3. Queues are expected to be created by client applications. Operator creates a headless service and service for each pod in the cluster setup.

Whenever client connects to a pod ,it creates a queue in that broker pod.So if client connects to 3 brokers at random time, three queues gets created in pods, one in each pod respectively.So when a producer sends message to the queue, it is sent to the connected pod. It wont be present in each broker pod.(No replication of messages).

My question is what service name should client applications use inorder to connect to artemis pods and also maintain session affinity? In other words, what should be done in order to make a client connect to same broker whenever it tries a connection?(and avoid duplicate queue creation)

What I currently use is a kubernetes clusterip service I created that splits traffics to pods.And queues are created via stomp producer.

Answer 1

Not sure which helm it will be using in the background but you will be using the service name inside the kubernetes app for connection instead of the ClusterIP.

Service name could be starting the with helm chart name. i was checking and referring this chart for ref : https://github.com/deviceinsight/activemq-artemis-helm could be different.

Looks like it's creating the service with Cluster IP:none (Headless service) so connecting to the existing service is not working, i doubt currently it might be returning all the PODs IP.

Option : 2 if above one not work give try to this

In another case, you can create the new service type clusterIP with a different name, everything else will be the same, like port and all.

In service you can notice amqp, mqtt and other port, so you app will connect to new service with port config as per requirement. For example : active-mq-service:61613

If everything working fine for you and you are just looking for session affinity you can add this config to your service and it will start managing the session affinity.

SessionAffinity: ClientIP

If you want to make sure that connections from a particular client are passed to the same Pod each time, you can select the session affinity based on the client's IP addresses by setting service.spec.sessionAffinity to "ClientIP" (the default is "None"). You can also set the maximum session sticky time by setting service.spec.sessionAffinityConfig.clientIP.timeoutSeconds appropriately. (the default value is 10800, which works out to be 3 hours).

Ref doc : https://kubernetes.io/docs/concepts/services-networking/service/