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Build Kubernetes Operators in Java Without Hassle

Java Operator SDK is a production-ready framework that makes implementing Kubernetes Operators in Java easy.

It provides a controller runtime, support for testing operators, and related tooling. In addition to that implementing conversion hooks and dynamic admission controllers are supported as a separate project (and much more, see related projects section).

Under the hood it uses the excellent Fabric8 Kubernetes Client, which provides additional facilities, like generating CRD from source code (and vice versa).


Documentation can be found on the JOSDK WebSite.

Contact us

Join us on Discord or feel free to ask any question on Kubernetes Slack Operator Channel

Meet us every Thursday (17:00 CET) at our community meeting on Zoom (Password in the Discord channel, or just ask for it there!)

How to Contribute

See the contribution guide on the website.

What is Java Operator SDK

Java Operator SDK is a higher level framework and related tooling to support writing Kubernetes Operators in Java. It makes it easy to implement best practices and patterns for an Operator. Features include:

  • Optimal handling Kubernetes API events
  • Handling dependent resources, related events, and caching.
  • Automatic Retries
  • Smart event scheduling
  • Handling Observed Generations automatically
  • Easy to use Error Handling
  • ... and everything that a batteries included framework needs

For all features and their usage see the related section on the website.

Related Projects

Projects using JOSDK

While we know of multiple projects using JOSDK in production, we don't want to presume these projects want to advertise that fact here. For this reason, we ask that if you'd like your project to be featured in this section, please open a PR, adding a link to and short description of your project, as shown below:

  • ExposedApp operator: a sample operator written to illustrate JOSDK concepts and its Quarkus extension in the "Write Kubernetes Operators in Java with the Java Operator SDK" blog series.
  • Keycloak operator: the official Keycloak operator, built with Quarkus and JOSDK.
  • Apache Flink Kubernetes operator is the market leader among Flink operators.
  • Strimzi Access operator. While the core Strimzi operator development predates
    JOSDK, but new components like the Access operator is using the framework.
  • EureKubeOperator: integrates service discovery of Eureka and Kubernetes using the framework - developed by 11street. It is not released as an open source yet but is very interesting to read about this problem and how it is solved by an operator written with JOSDK.
  • Locust k8s operator: Cloud native solution to run performance tests on any Kubernetes cluster.
  • Strimzi Schema Registry Operator: A Schema Registry Operator based on JOSDK for running the Confluent Schema Registry with a Strimzi-based Kafka cluster.
  • Airflow Dag Operator: Use JOSDK(Quarkus Extension) to replace Airflow Git Sync strategy. The main idea of the project is to start a synchronization container on each airflow pod to synchronize the DAG/files into the DAG folder.
  • Glasskube Operator: simplifies the deployment, maintenance and upgrade of popular open source business tools. It is written in Kotlin and uses the JOSDK and fabric8 Kubernetes client with Kotlin-based DSL.
  • Debezium Operator: Debezium Operator adds Change-Data-Capture capabilities to your Kubernetes or Openshift cluster by providing an easy way to run and manage Debezium Server instances.