Crossplane

Crossplane is an open-source control plane for Kubernetes that enables declarative, multi-cloud infrastructure management. It allows users to provision and manage external infrastructure and services—such as cloud databases, caches, and networking—directly from the Kubernetes API, using Kubernetes-native resources.

Architecture and concepts: It centers on Kubernetes CustomResourceDefinitions (CRDs) and a set of resource types that model both cloud providers and the infrastructure they manage. Providers connect to cloud accounts (AWS, Google Cloud, Azure, etc.) via Provider and ProviderConfig resources. Users describe higher-level infrastructure needs with CompositeResourceDefinitions and Composition, and then create resource claims that Crossplane satisfies by provisioning one or more managed resources on the configured providers.

Operation: Crossplane runs as a set of controllers inside a Kubernetes cluster and reconciles desired state with external cloud state. It supports multi-cloud environments, enabling a single Kubernetes API surface to provision resources across providers.

Usage and ecosystem: Crossplane is licensed under Apache 2.0. It can be installed via Helm or manifests and integrates with Kubernetes tooling and CI/CD. It has providers for major clouds and services and supports governance features and policy through external tools.

History: Crossplane originated as an open-source project maintained by Upbound and community contributors, with ongoing development and adoption in the Kubernetes ecosystem. It has been developed to provide Kubernetes-native infrastructure provisioning and to complement existing infrastructure-as-code tools.