Building Kubernetes Operators in Java with Java Operator SDK

Kubernetes Operators extend the Kubernetes API to automate the management of complex, stateful applications — but most operator frameworks are written in Go. Java Operator SDK (JOSDK), a CNCF project, brings first-class operator development to the Java ecosystem, letting teams leverage their existing Java expertise, libraries, and tooling.

In this talk, I'll walk through what Kubernetes Operators are, why they matter, and how JOSDK makes building them in Java straightforward. We'll go from zero to a working operator: defining a Custom Resource, implementing a Reconciler, managing dependent resources, and testing the operator with JUnit — all without writing a single line of Go and writing the whole project in Java. I will be going through working example in the session: https://github.com/ash-thakur-rh/microservice-operator

Under the hood, JOSDK is powered by the Fabric8 Kubernetes Client — a project I actively contribute to as a maintainer. I'll share how the client's event handling, watch mechanisms, and API abstractions make JOSDK's "magic" possible, and how contributing upstream directly improves the operator development experience.

Whether you're a Java developer curious about Kubernetes extensibility or already running workloads on Kubernetes and want to automate their lifecycle, this talk will give you a practical starting point.

- What Kubernetes Operators are and when you should (and shouldn't) build one

- How to scaffold and build an operator in Java using JOSDK — Custom Resources, Reconcilers, and Dependent Resources

- How to get involved — contributing to JOSDK, Fabric8, and the wider Kubernetes Java ecosystem