Kube-apiserver is the central hub and access gateway to a Kubernetes cluster. This topic introduces the kube-apiserver component. This topic also describes the usage notes and release notes for kube-apiserver.
Introduction
Kube-apiserver validates and configures data for the API objects, which include pods, Services, and ReplicationControllers. Kube-apiserver serves REST operations and provides a frontend to the shared state of the cluster. All other components interact through this frontend.
Usage notes
Kube-apiserver is automatically installed. You can use it without additional configurations.
In clusters that run Kubernetes 1.20 or later and are created after February 2023, elastic network interfaces (ENIs), instead of Classic Load Balancer (CLB) instances, are used to expose Services in the default namespace. Using ENIs provides faster connection speeds and higher bandwidth.
If the security group of a cluster forbids inbound traffic through port 6443 and the security group of the cluster nodes and containers that run on the nodes is different from the security group of the cluster, the system components of the cluster may fail to access the kube-apiserver of the cluster.
Release notes
Kube-apiserver is updated along with the Kubernetes version. For more information, see Overview of Kubernetes versions supported by ACK.