CoreOS Introduces the Operator Framework: Building Apps on Kubernetes
You may be familiar with Operators from the concept’s introduction in 2016. An Operator is a method of packaging, deploying and managing a Kubernetes application. A Kubernetes application is an application that is both deployed on Kubernetes and managed using the Kubernetes APIs and kubectl tooling.
To be able to make the most of Kubernetes, you need a set of cohesive APIs to extend in order to service and manage your applications that run on Kubernetes. You can think of Operators as the runtime that manages this type of application on Kubernetes.