Operators | Notion

Operators automate managing the entire lifecycle of distributed stateful applications deployed in the cluster. K8s cannot do this natively as it requires application specific knowledge to do so.
Operators are specific to the stateful application they manage. This is because different stateful applications like MySQL, ElasticSearch, etc. have different ways of setting up a distributed DB.
Operators use CRDs to extend the K8s API. So, we have operators for MySQL, Prometheus, Postgres, etc.
Operators monitor the stateful resources like a controller and makes the necessary changes if required.
Operator for a stateful application is built by experts in that application. The operator contains information like:
- How to setup a multi-instance cluster?
- How to run the cluster?
- How to sync data between instances?
- How to update the application instances?
Operators can be looked up on OperatorHub. These are built by the community.