Crossplane is an open-source, cloud-native control plane framework built on top of Kubernetes. It enables you to build your own custom control planes to manage and orchestrate applications and infrastructure across multiple cloud providers or on-premises environments.

• **Extensible Control Plane:** Crossplane extends the Kubernetes control plane, allowing you to define and manage custom resources representing your infrastructure and applications.
• **Custom Resource Definitions (CRDs):** Crossplane leverages CRDs to define new object types within the Kubernetes API, representing abstractions for various cloud services or infrastructure components.
• **Controllers and Reconciliation:** It provides a framework for building controllers that watch for changes to your custom resources and take actions to reconcile the desired state (defined in the resource) with the actual state of the underlying cloud or infrastructure resources.
• **Composition:** Crossplane enables you to compose multiple custom resources to represent complex applications or infrastructure stacks, simplifying management and deployment.
• **Portability:** Crossplane's cloud-agnostic nature allows you to manage resources across different cloud providers or on-premises environments using a unified interface and consistent workflows.

• **Unified Infrastructure Management:** Crossplane provides a single, centralized control plane for managing your applications and infrastructure across multiple clouds or on-premises environments, simplifying operations and reducing complexity.
• **Declarative Management:** The declarative nature of custom resources makes it easier to define and manage your desired infrastructure state, promoting consistency and reproducibility.
• **Self-Service Provisioning:** Crossplane empowers developers to provision and manage cloud resources directly through the Kubernetes API, reducing reliance on manual processes and improving agility.
• **Extensibility:** The ability to create custom resource definitions and controllers allows you to tailor Crossplane to your specific needs and integrate with any cloud provider or infrastructure technology.
• **Cloud-Native Ecosystem:** By leveraging Kubernetes' core capabilities and ecosystem, Crossplane integrates seamlessly with other cloud-native tools and workflows.

While Crossplane is primarily about defining custom resources and controllers, here's a conceptual example of a custom resource definition for a managed database:

```yaml apiVersion: database.crossplane.io/v1alpha1 kind: PostgreSQLInstance metadata:

 name: my-database

 parameters:
   engineVersion: "13"
   storageType: "gp2"
   storageSize: "10Gi"
 providerRef:
   name: aws  # Reference to an AWS cloud provider

This configuration defines a custom resource of type `PostgreSQLInstance` representing a PostgreSQL database. It specifies parameters like the engine version and storage configuration, along with a reference to an AWS cloud provider. Crossplane's controllers would then handle the provisioning and management of the actual database instance on AWS based on this declarative configuration.

• **Crossplane Official Website:** s://crossplane.io/(https://crossplane.io/)
• **Crossplane GitHub Repository:** s://github.com/crossplane/crossplane(https://github.com/crossplane/crossplane)
• **Crossplane Documentation:** s://doc.crds.dev/github.com/crossplane/crossplane(https://doc.crds.dev/github.com/crossplane/crossplane)