OpenShift Architecture

Objective of this article to share high level architecture of Red Hat OpenShift. OpenShift uses Kubernetes as basic infrastructure which is Kubernetes built on top of the Docker.

This is to recollect about Kubernetes and how we use to manage applications. As we already learn in previous articles that any application can be deployed in Kubernetes as Docker Containers. In general, Containers are created on top of the Docker images. Docker images comes from different sources depending on our configuration like cloud, docker registry (Docker hub), repository or etc. Services are used to expose the applications other services or external world in Kubernetes.

OpenShift comes with web console which can be accessible by developers to browse and manage applications. OpenShift web console can be accessed only users who are authorized with OpenShift authentication. OpenShift also comes with built-in integration to manage source code. The source code repository has integrated to built-in CI/CD integration to build docker images and deploy into docker registry.

The etcd (“/etc distributed”) is the heart of the OpenShift to store various containers information in Key-Value pairs. As shown in the above image, the content which is present right side of etcd is specific to Kubernetes where the left side information points few among the many add-ons in OpenShift.

What is etcd?

Etcd stands for “/etc distributed”. It is meant to be a highly reliable configuration mechanism that provides a uniform view across a cluster of machines.

What is Master Node?

Master Node Architecture

As shown in the above image, Kubernetes Clusters are configured with multiple nodes where multiple Docker Images are hosted. These nodes are managed by one or more master nodes who hosts the API data server. For example, etcd data server and Schedulers.

Architectural differences:

Red Hat provides, and periodically updates, a comprehensive Reference Architecture document specific to deploying Red Hat OpenShift Container Platform on the most popular Cloud Infrastructure Providers:

  • Red Hat OpenStack Platform
  • Amazon Web Services (AWS)
  • Microsoft Azure public cloud
  • Google Cloud Platform (GCP)
  • VMware vSphere
  • Red Hat Virtualization (RHV)

Link to discover more on your own.