Document URL:
https://docs.openshift.com/container-platform/4.10/installing/installing_bare_metal/installing-bare-metal.html#rhcos-enabling-multipath_installing-bare-metal
Section Number and Name:
Enabling multipathing with kernel arguments on RHCOS
Describe the issue:

The documents is supposedly for enabling multipath at installation time.

The listed prerequisites are:
1. You have a running OpenShift Container Platform cluster that uses version 4.8 or later.

2. You are logged in to the cluster as a user with administrative privileges.

If I have a running OCP cluster, how can it be at installation time?

Also,

The following procedure has this first step:
To enable multipath and start the multipathd daemon, run the following command:

$ mpathconf --enable && systemctl start multipathd.service

Where should the user execute this command?