Crossplane Documentation

What Crossplane is

Crossplane describes itself as a control plane framework for platform engineering. In practice it lets a platform team extend Kubernetes with its own APIs. Instead of handing product teams a folder of Terraform, you publish a resource such as Database or App, and when a team creates one, Crossplane provisions and keeps reconciling everything behind it: the cloud database, its network rules, the secret with credentials. Upbound created it and donated it to the CNCF in 2020; it became incubating in 2021 and graduated in November 2025.

What the docs cover

• What's Crossplane and Get Started: the core idea and installing it into a cluster with Helm.
• Composition: composite resource definitions (the API you publish), composite resources (what users create) and compositions (the template of resources behind them), built with composition functions that hold the logic.
• Managed resources and providers: the building blocks that map one to one to cloud resources, supplied by providers for AWS, Azure, Google Cloud and many other systems.
• Operations: running scheduled or event-driven operational tasks, one of the features Crossplane v2 introduced.
• Packages: how providers, functions and configurations are packaged and installed.
• Guides, CLI and API reference: worked tasks, the crossplane command line tool and every resource type.

The current docs are for Crossplane v2. The biggest change from v1 is that composite resources are namespaced and can compose any Kubernetes resource, not only cloud infrastructure, which makes it a better fit for application platforms. Use the version selector, because many blog posts still describe v1 with claims and cluster-scoped resources.

Is it worth learning?

If you are building an internal platform on Kubernetes, yes. It is the CNCF's graduated answer to "how do I offer self-service infrastructure with guard rails", and it shows the platform-as-an-API idea from the CNCF platforms white paper in working form. If you only need to provision a few resources for one team, plain Terraform or OpenTofu is simpler, and it is fine to start there.

Prerequisites and time

You need solid Kubernetes: custom resources, controllers at a conceptual level, namespaces and RBAC. You also need one cloud provider account, or you can compose plain Kubernetes resources to practise without one. Expect a weekend to install it and create your first managed resource, and one to two weeks to design and test a useful composition.

Free or paid

Crossplane and its documentation are free and open source under the Apache 2.0 licence. Commercial distributions and support exist from vendors, but none are needed to learn or use it.

What you can do after it

• Publish a self-service API that provisions a database and its credentials for a team.
• Enforce defaults such as encryption, regions and sizes inside a composition.
• Explain the difference between infrastructure as code that runs once and a control plane that keeps reconciling.

Best for: platform engineers who already know Kubernetes well and want to offer infrastructure as a product.