Completing the largest migration in Kubernetes history

Kubernetes has removed built-in cloud provider integrations to enhance vendor neutrality and simplify maintenance. Four new subsystems were created to achieve full feature parity with built-in capabilities: cloud controller manager, API server network proxy, kubelet credential provider plugins, and storage migration to CSI. The cloud controller manager initializes nodes, applies metadata labels, and runs the service controller. The API server network proxy provides a generic proxying mechanism for secure traffic between the control plane and nodes. Kubelet credential provider plugins enable the kubelet to fetch credentials for image registries hosted on various clouds. Storage migration to CSI involves using external drivers to manage storage systems, with an API translation layer ensuring backwards compatibility. The migration has reduced the Kubernetes codebase by approximately 1.5 million lines and binary sizes by 40%. SIG Cloud Provider will now focus on improving integration with cloud providers in hybrid environments and simplifying integration efforts for external providers. Testing capabilities for cloud controllers will be enhanced to include more providers. In-tree cloud providers will be disabled and removed in Kubernetes v1.31. Users are encouraged to migrate to external cloud providers before v1.31.