Add real time kernel workers with OCP 4.x and UPI

The purpose of this repo is to describe the enroll of CentOS-RT nodes on an existing OCP 4.x cluster based on baremetal (using UPI workflow)

Introduction

This procedure is based on the baremetal instructions for OCP 4.1 : https://docs.openshift.com/container-platform/4.1/installing/installing_bare_metal/installing-bare-metal.html . What is shown here is an implementation of those instructions based on matchbox for PXE and terraform for automation.

How does it work

Pre-requisites

Initial cluster deployment

Kickstart generation

Enroll worker

Credits

This is heavily based on: https://github.com/e-minguez/ocp4-upi-bm-pxeless-staticips https://github.com/openshift/installer/tree/master/upi/metal