cdk8s defines Kubernetes applications with familiar programming languages

cdk8s defines Kubernetes applications in code

cdk8s is an open-source software development framework for defining Kubernetes applications and reusable abstractions using familiar programming languages and rich object-oriented APIs. Instead of writing YAML by hand, a developer writes a program whose constructs describe the desired cluster state. When that program runs, cdk8s synthesizes standard Kubernetes manifests that can be applied to any Kubernetes cluster. Kubernetes itself is an open-source system for automating the deployment and management of containerized applications, so cdk8s fits into the same workflow while keeping the definition in code. The framework is a Cloud Native Computing Foundation Sandbox Project and was built at AWS, and the project invites users to try it, leave feedback, and contribute to its development.

Programs are organized as a tree of constructs

cdk8s apps are programs written in one of the supported programming languages. They are structured as a tree of constructs, which are the building blocks of a cdk8s application. The root of the tree is an App construct. Within an app, users define any number of charts, which are classes that extend the Chart class. Each chart is synthesized into a separate Kubernetes manifest file. Charts are, in turn, composed of any number of constructs and eventually of resources, which represent any Kubernetes resource such as Pod, Service, Deployment, ReplicaSet, and others. This nested model lets teams build small reusable pieces and compose them into larger applications without repeating manifest boilerplate.

Synthesis turns charts into standard manifests

cdk8s apps only define Kubernetes applications; they do not actually apply them to the cluster. When an app is executed, it synthesizes all the charts defined within the app into the dist directory. Those charts can then be applied to any Kubernetes cluster using kubectl apply with a command such as kubectl apply -f dist/chart.k8s.yaml, or by a GitOps tool such as Flux. This separation means cdk8s is a definition and synthesis layer rather than a deployment engine. The synthesized manifests are plain Kubernetes YAML, so any standard tooling that consumes manifests works with the output without special support, and the same artifacts can move between environments.

Several packages make up the project

The project consists of multiple packages maintained and released through separate repositories. The cdk8s package is the core library, and for historical reasons it is maintained in the cdk8s-team/cdk8s-core repository. The cdk8s-cli package provides the command-line interface. The cdk8s-plus package offers high-level constructs for Kubernetes core. The repository that holds the umbrella documentation acts as a cross-module concern hub and also handles deployment of the cdk8s.io website. Treating each package as its own release unit lets the team evolve the core, the CLI, and the higher-level constructs on their own schedules while keeping a single place for shared concerns.

Based on AWS CDK ideas and a CNCF Sandbox project

cdk8s is based on the design concepts and technologies behind the AWS Cloud Development Kit, and it can interoperate with AWS CDK constructs. That means a single cloud-native application can include both Kubernetes resources and other CDK constructs as first-class citizens. The project is also a Cloud Native Computing Foundation Sandbox Project, which places it within the broader cloud-native ecosystem alongside Kubernetes and related tooling. Readers can learn more through the project blog or a CNCF webinar that shows a live demo of cdk8s in action. The connection to AWS CDK explains why cdk8s uses the same construct programming model already familiar to CDK users.

Help, documentation, and community

The project points users to several support and learning channels. Documentation lives at cdk8s.io/docs, and a Getting Started guide walks new users through their first app. For help, the project suggests searching open issues first, then asking on Stack Overflow under the cdk8s tag, filing a new issue, or joining the #cdk8s channel on the cdk.dev Slack. Examples are collected in an examples directory, and community work is gathered in an Awesome cdk8s list. Adopters are encouraged to add their name to the ADOPTERS file. These channels separate end-user questions from code contributions and keep discussion easy to find.

License and how to contribute

cdk8s is distributed under the Apache License, Version 2.0. The project follows the CNCF Code of Conduct and welcomes community contributions and pull requests through a contribution guide that explains how to report issues, set up a development environment, and submit code. A public roadmap describes the team's plans for the project. Because the work spans multiple repositories, contributors are directed to the specific package repository that matches the change they want to make, whether that is the core library, the command-line interface, or the high-level constructs. This structure keeps contributions focused, reviewable, and aligned with the right maintainers.

Editorial conclusion

cdk8s gives developers a way to define Kubernetes applications and reusable abstractions using familiar programming languages and object-oriented APIs, then synthesize them into standard manifests that any cluster can consume. By modeling apps as a tree of constructs rooted in an App and composed from charts and resources, it keeps definitions in code while staying compatible with kubectl and GitOps tools such as Flux. Distributed under the Apache 2.0 license and backed by a CNCF Sandbox status, it fits teams that already use the AWS CDK programming model.

Frequently asked questions

Official sources

1. cdk8s-team/cdk8s on GitHub
2. License: Apache-2.0
3. Project website
4. README
5. Releases