Kubernetes control plane is responsible for controlling the cluster and manages the cluster state and configuration data. Read on.
The Kubernetes control plane is one of the two parts of Kubernetes clusters. To refresh your knowledge, Kubernetes is an open source container orchestration system that can automate application deployment, scaling, & management. The other part of the clusters is the nodes or the computing machines.
The control plane is responsible for controlling the cluster. It acts as the central hub of a Kubernetes cluster and manages the cluster state and configuration data. However, the control plane is highly prone to attacks because it is not easy to configure.
Kubernetes Control Plane Components
The Kubernetes control plane consists of multiple components, where each piece manages its own process. These components can run on a single master node or multiple master nodes supporting high-availability clusters.
etcd
etcd is a persistent, distributed, and lightweight key-value data store. It is developed by CoreOS that stores the cluster configuration data, representing the overall cluster state at a given point of time. etcd favors consistency over availability in the event of network partitions. This consistency is crucial to maintaining the correct scheduling and operation of services. The K8s API Server uses etcd's watch API in monitoring the cluster and roll out critical configuration changes or restore any divergences of the state of the cluster to what was declared by the deployer.
API Server
The API server is a crucial component of the control plane and serves the Kubernetes API using JSON instead of HTTP, providing both internal and external interfaces to Kubernetes. It processes and validates REST requests and updates the state of API objects in etcd, allowing workload and container configuration on worker nodes.
