slcraciun/scalable-elassandra-deployment-on-kubernetes

Scalable Kubernetes based deployment of Elassandra using statefulsets

Scalable multi-node Elassandra deployment on Kubernetes Cluster

This recipe is mostly based on this repository, but it is modified for Elassandra. It uses statefulsets for storing data persistantly and it is easy to scale up and down!

It is assumed that you are already familiary with Cassandra, EalsticSearch and Kubernetes and you have a working Kubernetes cluster.

tldr;

$ kubectl create -f elassandra-service.yaml
$ kubectl create -f local-volumes.yaml
$ kubectl create -f elassandra-statefulset.yaml

Elassandra service

First the Elassandra service is defined and the relevant ports are exposed:

$ kubectl -f elassandra-service.yaml

Check to verify the service is created:

$ kubectl get svc elassandra

Local volumes

Then the local volumes are created:

$ kubectl create -f local-volumes.yaml

To verify it:

$ kubectl get pv

Statefulsets

Then the pods are created using the statefulset definition:

$ kubectl create -f elassandra-statefulset.yaml

And to verify the statefulset:

$ kubectl get statefulsets

Scaling up and down

With this sample script, only three persistant volumes are created - so if you want to scale to more than three pods, first create the pvs accordingly.

$ kubectl scale statefulset elassandra --replicas=3

And to verify the state of the statefulset:

$ kubectl get statefulsets

Accessing the cluster

Assuming that the default namespace was used, the service is accessible via elassandra.svc.default.cluster.local

Checking Cassandra nodes:

$ kubectl exec -ti elassandra-0 nodetool status

Checking ElasticSearch status:

$ curl http://elassandra.svc.default.cluster.local:9200