Feature Overview (aka. Goal Summary)  

As an OpenShift administrator I want to install OpenShift to a specific host disk partition and maintain one or more existing partition.

Why is this important?

We have partners that use multiple partitions. For example they want to retain one partition to host a rescue/maintenance OS that is used to install the operating system (ie. CoreOS) to a second partition, the Agent installer should not delete existing partitions and take the whole disk.

Existing functionality in UPI

This is fully supported in UPI today with the coreos-installer:

https://docs.openshift.com/container-platform/4.12/installing/installing_bare_metal/installing-bare-metal.html#installation-user-infra-machines-advanced_retaindisk_installing-bare-metal