OCP4-IPI-libvirt

Introduction

What I Assume

• You are familiar and comfortable with libvirt CLI and XML.
• You are familiar and comfortable with qemu-img tool.
• You understand the different types of network interfaces on Linux and different libvirt networks.
• You know how OpenShift installation works and what the difference between IPI and UPI is.
• You know about the OpenShift Machine API and various underlying mechanisms.

Outcomes

The installation described is for a fully managed IPI running OpenShift Container Platform v4.14, initially with three master and two worker nodes.

At a later point, I will add a couple of steps needed to grow the cluster by one extra worker node.

OpenShift Container Platform IPI Installation Using Libvirt

Prerequisites

Hardware requirements for the cluster:

• 136 GiB RAM (32 GiB per control plane, 20 GiB per compute node), max overcommit ratio of 1.5 (make sure enough swap is available)
• 52 vCPUs (12 per control plane, 8 per compute node), max overcommit ratio of 1.3 (may work with more, but will slow down the installation horribly and may ultimately fail)
• one physical network interface that will be used for the public bridged network
• a physical or virtual network interface that will be used for the provisioning network bridge

Hardware requirements for the installation client (provisioner) machine:

• a minimum of 8 GiB RAM and 4 CPUs
• a network connection to both the public bridged network and the provisioning network

Due to the fact provisioner needs access to both networks, and the provisioning network in this guide is a virtual one, it might be best if you define the provisioner as a VM, with the same network interface settings as the control/compute nodes.

In the case you want to run the workloads spread across several hypervisor hosts, there are some extra steps, but nothing big. More on that in #Host Configuration below.

Software artifacts needed on the provisioner host:

• oc, the command line client, of the corresponding version - download from https://mirror.openshift.com/pub/openshift-v4/clients/ocp/
• libvirt-client package is required for openshift-baremetal-install to be able to communicate to hypervisors
• ipmitool or some other IPMI client
• a pull-secret file containing authentication credentials for OpenShift Container Platform registries - download from https://console.redhat.com/openshift/
• an SSH keypair that can be used for accessing OpenShift nodes