Overview
The control plane is the orchestration layer of Kubernetes. It makes global decisions about the cluster (such as scheduling) and detects and responds to cluster events (such as starting up a new pod when a deployment's replicas field is unsatisfied).
Key Components
- kube-apiserver: The front end for the Kubernetes control plane.
- etcd: Consistent and highly-available key-value store used as Kubernetes' backing store for all cluster data.
- kube-scheduler: Watches for newly created Pods with no assigned node, and selects a node for them to run on.
- kube-controller-manager: Runs controller processes (e.g., Node Controller, Job Controller).
- cloud-controller-manager: Links your cluster into your cloud provider's API.
Importance
The control plane ensures that the cluster's actual state matches the desired state defined by the user.