Red Hat Bugzilla – 1910199 – [GSS] The "External" mode option is not available when the OCP cluster is deployed using Redhat Cluster Assisted Installer 4.6.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory (OpenShift Container Platform 4.6.20 bug fix update), and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
https://access.redhat.com/errata/RHBA-2021:0674