The Cluster API Book

Note: Impatient readers may head straight to Quick Start.

Using Cluster API v1alpha1? Check the legacy documentation

What is the Cluster API?

The Cluster API is a Kubernetes project to bring declarative, Kubernetes-style APIs to cluster creation, configuration, and management. It provides optional, additive functionality on top of core Kubernetes to manage the lifecycle of a Kubernetes cluster.


  • To manage the lifecycle (create, scale, upgrade, destroy) of Kubernetes-conformant clusters using a declarative API.
  • To work in different environments, both on-premises and in the cloud.
  • To define common operations, provide a default implementation, and provide the ability to swap out implementations for alternative ones.
  • To reuse and integrate existing ecosystem components rather than duplicating their functionality (e.g. node-problem-detector, cluster autoscaler, SIG-Multi-cluster).
  • To provide a transition path for Kubernetes lifecycle products to adopt Cluster API incrementally. Specifically, existing cluster lifecycle management tools should be able to adopt Cluster API in a staged manner, over the course of multiple releases, or even adopting a subset of Cluster API.


  • To add these APIs to Kubernetes core (kubernetes/kubernetes).
    • This API should live in a namespace outside the core and follow the best practices defined by api-reviewers, but is not subject to core-api constraints.
  • To manage the lifecycle of infrastructure unrelated to the running of Kubernetes-conformant clusters.
  • To force all Kubernetes lifecycle products (kops, kubespray, GKE, AKS, EKS, IKS etc.) to support or use these APIs.
  • To manage non-Cluster API provisioned Kubernetes-conformant clusters.
  • To manage a single cluster spanning multiple infrastructure providers.
  • To configure a machine at any time other than create or upgrade.
  • To duplicate functionality that exists or is coming to other tooling, e.g., updating kubelet configuration (c.f. dynamic kubelet configuration), or updating apiserver, controller-manager, scheduler configuration (c.f. component-config effort) after the cluster is deployed.

Community, discussion, contribution, and support

  • Chat with us on the Kubernetes Slack in the #cluster-api channel
  • Subscribe to the SIG Cluster Lifecycle Google Group for access to documents and calendars
  • Participate in the conversations on Kubernetes Discuss
  • Join our Cluster API working group sessions where we share the latest project news, demos, answer questions, and triage issues
  • Provider implementers office hours where you can ask questions related to developing providers for Cluster API
    • Weekly on Tuesdays @ 12:00 PT (Zoom) and Wednesdays @ 15:00 CET (Zoom)
    • Previous meetings: [ notes ]

Pull Requests and feedback on issues are very welcome! See the issue tracker if you’re unsure where to start, especially the Good first issue and Help wanted tags, and also feel free to reach out to discuss.

See also: our own contributor guide and the Kubernetes community page.

Code of conduct

Participation in the Kubernetes community is governed by the Kubernetes Code of Conduct.