Understanding the foundational concepts
Let's start by understanding the main concepts related to Kubernetes and OpenShift components and servers. First, any OpenShift cluster is composed of two types of servers: master and worker nodes.
Master nodes
This server contains the control plane of a Kubernetes cluster. Master servers on OpenShift run over the Red Hat Enterprise Linux CoreOS (RHCOS) operating system and are composed of several main components, such as the following:
- Application programming interface (API) server (
kube-apiserver
): Responsible for exposing all Kubernetes APIs. All actions performed on a Kubernetes cluster are done through an API call—whenever you use the command-line interface (CLI) or a user interface (UI), an API call will always be used. - Database (
etcd
): The database stores all cluster data.etcd
is a highly available distributed key-value database. For in-depth information aboutetcd
, refer to its documentation here: https...