Kubernetes admin

kube-apiserver

Master only component. Accepts user request. Stores resources definitions in etcd.

kube-scheduler

Master only component. Materializes user requests, watches the kube-apiserver, decides where and when schedule PODs. PODs definition may contain some data that affects kube-scheduler:

• affinity/anti-affinity
• nodeSelector
• taints/tolerations
• reservations/limits

It is possible to write custom scheduler

kube-controller-manager

Master only component. Monitors *-controllers, e.g., deployment-controller

kubelet

Master/Worker component. Resides on every Node. Connects to the kube-apiserver. Starts the actual containers via the container runtime. Provides health-checks

kube-proxy

Master/Worker component. Main network component, watches the services and materializes their rule on the Nodes (e.g. handles iptables)