This blog post looks at the most important control plane components of a single Kubernetes master node — etcd, the API server, the scheduler and the controller manager — and explains how they work together. Although other components, such as DNS and the dashboard, come into play in a production environment, the focus here is on these specific four.
etcd is a distributed key-value store written in golang that provides a reliable way to store data across a cluster of machines. Kubernetes uses it as its brain, but only the kube-apiserver can communicate to it to save desired states. To get an idea of how etcd works, download the latest binary version for your preferred operating system and just execute etcd. If you have a golang development environment ready on your system (on a Mac just do: brew install go), you can also clone the etcd GitHub repo and start a cluster with goremanas follows:
Read more at VMware