Kubernetes Cluster Architecture

Kubernetes Cluster Architecture An architecture diagram generated by Archify. kubectl / Client · API request · Architecture component kubectl / Client API request kube-apiserver · API frontend · Control Plane kube-apiserver API frontend etcd · key-value store · Control Plane etcd key-value store kube-scheduler · node selection · Control Plane kube-scheduler node selection kube-controller-manager · controllers · Control Plane kube-controller-manager controllers cloud-controller-manager · cloud provider API · Control Plane cloud-controller-manager cloud provider API kubelet · node agent · Worker Node kubelet node agent Container Runtime · containerd / CRI-O · Worker Node Container Runtime containerd / CRI-O Pods · running workloads · Worker Node Pods running workloads kube-proxy · network rules · Worker Node kube-proxy network rules kubectl / API read / write state watch pods watch / reconcile watch / reconcile assign pod CRI run forward traffic Control Plane Worker Node Legend Backend Database External

Control Plane

  • • kube-apiserver exposes the Kubernetes API
  • • etcd stores all cluster data
  • • kube-scheduler picks a node for new pods
  • • kube-controller-manager runs core controllers
  • • cloud-controller-manager talks to the cloud provider API

Worker Node

  • • kubelet manages containers on the node
  • • kube-proxy maintains network rules and forwarding
  • • the container runtime (containerd, CRI-O, ...) runs pods