Summary

Today an OpenShift cluster needs to be installed using networking
and DNS configuration where it will permanently reside.

There are scenarios where you may want to install OpenShift
plus a set of software on a system in one location, and then move the system
to another location. This would also involve modifying the OpenShift configuration
after it has been moved to another location where there are different networking
and DNS values.

This enhancement describes how to allow an OpenShift cluster to be
modified to a different set of networking and DNS values.

Motivation

Allow for OCP clusters to be incorporated into on-prem systems
and edge devices in such a way that it can be installed in one location and then
easily re-configured once the system or edge device is moved to another location.

Today an OCP cluster can only be installed once DNS and networking information
are known.

Goals

Allow an OCP cluster to be installed in one location and then
reconfigured with updated IP addresses, DNS information (cluster name,
base domain, host names etc), pull secret, disconnected image registry,
etc after it is moved to another location. Some of these values like pull secret
and image registry can be changed after install. Others such as cluster name,
base domain, etc cannot be changed today.

Non-Goals

Changing current installs as they work today. Goal is more to allow
for more flexibility in changing OpenShift configuration after install.

Proposal

The proposal is to allow among other fields necessary the ability
to change values originally set in install-config.yaml such as:

• cluster name
• base domain
• IP addresses of each compute and control node
• IP addresses of API and Ingress VIPs

The following values can already be changed after install completes

• Pull Secret
• Disconnected Registry information (Mirror Registry)

User Stories

Story 1

As a OpenShift administrator, I want to be able to run the OpenShift installer
in one location with a set of install-config values, and then move the system to
a new location and update the OpenShift networkign configuration for the new location.