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OCP on KVM

Table of Contents

Purpose

In the wild, libvirt/KVM based OpenShift installations are used for development, demo, PoC, and other, normally non-productive, purposes (see the official installer documentation).

Though different approaches exist addressing an automated OpenShift installation (see references below), they deploy to specific target environments. This project aims to be agnostic when it comes to installation platforms: Wherever RHEL 8 runs, this setup should work.

Design Principles

  1. Solution should work on different infrastructure setups.
  2. The number of nodes should easily be adjustable (i.e. 1/3/n master nodes etc).
  3. Specific setups for individual target platforms shall be made configurable, not hard coded.
  4. Ansible is used for automation (vs. Go/other lang individual programs).

General Setup

Prerequisites

  • Root access to your machine.
  • You need to have access to the Red Hat Enterprise Linux (RHEL) binaries. E.g. head over to Red Hat Developers and create an account.
  • Ansible 2.8++.
  • Terminal access.

Basic Steps I: What is done?

  1. KVM gets installed and set up.
  2. Based on an inventory file, a single KVM node ("Bootstrap" node) is created for further deployment of the cluster).
  3. When the bootstrap node is up, it is used to create the cluster nodes.

Basic Steps II: What do you need to do?

  1. Clone this repository (or make a fork: contributions welcome!):
git clone https://github.com/sa-mw-dach/ocp-on-kvm.git
cd ocp-on-kvm

  1. Login to RHN and download the RHEL 8.1 DVD image from https://access.redhat.com/downloads/content/479/ver=/rhel---8/8.1/x86_64/product-software and place it under /root, e.g. /root/rhel-8.1-x86_64-dvd.iso

  2. Create an individual SSH-Key

ssh-keygen -q -t rsa -f /root/.ssh/id_ocplabs -C "" -N ""
  1. Create an Ansible vault file.
touch group_vars/all/vault.yml

Put in this information and replace the placeholders <rhn-user> and <rhn-password>:

vault_rhn_user: <rhn-user>
vault_rhn_password: <rhn-password>

and encrypt it:

ansible-vault encrypt group_vars/all/vault.yml

Make sure you can remember the password given as you'll need it later.

  1. Create an inventory file.
touch inventory

Add content to the inventory file according to your infrastructure setup. You can find an example inventory file here.

  1. Run the playbook
ansible-playbook -vvv --ask-vault-pass -i inventory playbook.yml > ansible.log 2>&1

Target Architecture

The target architecture consists of the Bootstrap 1..3..5..n Master and 1..n Worker (aka Compute) nodes. Supportive functionality (DNS, DHCP) is provisioned on the Bootstrap node.

See this basic archictural diagram: High Level Architecture.

Tasks

The following paragraphs give an overview of the individual steps needed to setup the OpenShift cluster. These tasks are fully automated.

Setup KVM on RHEL 8.1

KVM/libvirt installation needed for running the OpenShift cluster. Deep explanation of many steps needed to be done can be found in the official OpenShift installer documentation.

Setup DNS

Installed unconditionally.

Setup NTP

Installed unconditionally.

Setup DHCP

Installed unconditionally.

Setup TFTP

Installed unconditionally.

Setup PXE-Boot for KVM

Check the `ìnventoryfile if your setup needs the various kvm_`` parameters.

(Optional) Add Bridging

If you don't think you need bridging, remove
kvm_network_mode=bridge
in your ìnventory file.

Update Firewall

Done unconditionally where needed.

Setup HTTP Server

Installed unconditionally.

Setup HA Proxy

Installed unconditionally.

(Optional) Setup Outbound Proxy

Needed if you want to simulate real life settings (like in TelCo) where all traffic is proxied. Done via

squid_install=True

in the inventory file.

(Optional) Setup Docker Repository (f.e. Nexus) for Detached Install

Nexus will be installed if you set

ocp_install_type=disconnected

and

nexus_version=<your-nexus-version>

e.g.

nexus_version=3.20.1-01

in the inventory file.

Stage and Extract Client and Installer

Done automatically.

Stage Secret

Still on the to-do list, see below. Contributions welcome!

Setup Ignition Config

Done automatically.

Create Ignition Config with Installer

Done automatically.

Copy Ignition Configs to HTTP Folder

Done automatically.

Start Bootstrap

Done automatically.

Install and Customize all VMs

Done automatically.

virsh start VMs

Done automatically.

Add Worker Nodes

Done automatically.

Reference, Inspiration, Links

In open source, you always stand on the shoulders of giants, so do we.

OCP4 UPI Helpernode
Comprehensive single node setup. The helper node acts as bastion and bootstrap node.

Hetzner OCP4
An automated installation From the Red Hat EMEA "Tigers", specifically targeting the Hetzner dedicated hosting environment (https://www.hetzner.com/sb).

OpenShift 4 IPI for Hetzner
Documentation of a KVM based IPI install on the Hetzner environment.

Some of us are actually giants in their own right ;) ...:

Ansible lab
From @jcordes73 - target platform is his famous "OpenShift-in-a-box" environment.

OCP4 Labs-Ansible
From @elajoie - derived from practical field work.

TO DO/WIP

Contributions welcome!

  • Stage secret automatically (see here).
  • Make RHEL DVD iso file placement configurable. (Unfortunately it doesn't seem possible automating the download).
  • Make a pre-check of your configuration.
  • Add the NFS role for the bastion node.
  • Configure/setup OpenShift Container Storage.