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).
Java Operator SDK is a CNCF project as part of Operator Framework.
Documentation can be found on the JOSDK WebSite.
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See the contribution guide on the website.
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
- Easy to use Error Handling
- ... and everything that a batteries included framework needs
For all features and their usage see the related sections on the website.
- Quarkus Extension: https://github.com/quarkiverse/quarkus-operator-sdk
- Spring Boot Starter: https://github.com/java-operator-sdk/operator-framework-spring-boot-starter
- Kubernetes Glue Operator: https://github.com/java-operator-sdk/kubernetes-glue-operator Meta-operator that builds upon to use JOSDK Workflows and Dependent Resources features and allows to create operators by simply applying a custom resource, thus, is a language independent way.
- Kubernetes Webhooks Framework: https://github.com/java-operator-sdk/kubernetes-webooks-framework Framework to implement Admission Controllers and Conversion Hooks.
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:
- Apache Flink Kubernetes Operator is the market leader among Flink operators.
- Apache Spark Kubernetes Operator emerging operator for Spark.
- kroxylicious Kafka proxy operator
- 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.
- Keycloak operator: the official Keycloak operator, built with Quarkus and JOSDK.
- Apache Hive Kubernetes Operator for the data warehouse system
- OpenMetadata Operator for AI context, data cataloging, and metadata management service
- Strimzi Access operator. While the core Strimzi operator development predates
JOSDK, but new components like the Access operator is using the framework. - Wanaku MCP Router Operator
- Apicurio Registry Operator to run the registry
- Kaap autoscaling Operator for Apache Pulsar
- 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.
- Gerrit Operator for running the code review tool
- 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.
- 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.