Bug 1878830

Document URL: 
https://docs.openshift.com/container-platform/4.6/installing/install_config/installing-restricted-networks-preparations.html#installation-mirror-repository_installing-restricted-networks-preparations

Section Number and Name: 
 OpenShift Container Platform / Installing / Installation configuration / Creating a mirror registry for a restricted network / Mirroring the OpenShift Container Platform image repository

Describe the issue: 
Two separate scenarios are covered under this section:
1. Internet connectivity is available from the registry host
2. Internet connectivity is not available from the registry host

With the second scenario we need clear demarcation between:
- the steps that need to be done on the machine having internet connectivity
- the steps that need to be done on the registry host

This is missing in two places:

a.) The definition of environment variable. This needs to be done twice with scenario 2: on the machine having internet connectivity and on the registry host. This is the common use case where the registry host is in a completely fenced network zone and cannot communicate with the machine with internet access.

b.) The extraction of the installation program. This needs to be done on the machine having internet connectivity due to bug 1823143. The files then need to be placed on the removable media and physically moved like the registry content. 
The command for this in the documentation has a few issues:
$ oc adm -a ${LOCAL_SECRET_JSON} release extract --command=openshift-install "${LOCAL_REGISTRY}/${LOCAL_REPOSITORY}:${OCP_RELEASE}-${ARCHITECTURE}"

- it should happen before the removable media is moved to the registry host. The step for copying the file to it needs to be added.
- From the tests I did with 4.6.0-fc.5 the command failed with "-${ARCHITECTURE}" and succeeded without it.
- according to the contextual help "--from" should be used for specifying the image containing the release payload. Also both seem to give the same result.

Suggestions for improvement:
See above

Additional information: 
Investigating whether the issue with -${ARCHITECTURE}" is specific to the pre-release version.