Building Enterprise JavaScript Applications

Working with StatefulSets

So far, we've been using the Deployment object to deploy our Elasticsearch service. The Deployment Controller will manage the ReplicaSets and Pods under its control and ensure that the correct numbers are running and healthy.

However, a Deployment assumes that each instance is stateless and works independently from each other. More importantly, it assumes that instances are fungible—that one instance is interchangeable with any other. Pods managed by a Deployment have identical identities.

This is not the case for Elasticsearch, or other distributed databases, which must hold stateful information that distinguishes one Elasticsearch node from another. These Elasticsearch nodes need individual identities so that they ...