Main Architecture

Structure

A K8S cluster is consist of master node(s) and worker node(s). All nodes are networking connected and could talk to each other.

DNS server is also part of master server which is not shown in the diagram above

Master node: etcd, Controller Manager, Scheduler and API Server are running on it. You will the corresponding Linux processes are running on the master node.

etcd

controller manager

scheduler

API Server

From v1.14 cloud-controller-manager was added. So we have kube-controller manager and cloud-controller-manager as the controller manager

Worker node: kubelet is running on it

On worker node, there could be kube-proxy as well

Command line tools

All components mentioned above have corresponding executable binaries which are packaged each node. The locations of those binaries are different based on how you install the K8S cluster. In PKS, the K8S binaries are under /var/vcap/packages . And etcd is only on master node.

So, if you want to play with those command line tools, you could go to your K8s node check out the binary location and run it for fun.

Official doc about those command line tools could be found here.