The current RHBK documentation uses the ":latest", which is wrong.  It is not supported by RHBK 

~~~
FROM registry.redhat.io/rhbk/keycloak-rhel9:latest as builder#

...
Enable health and metrics support
ENV KC_HEALTH_ENABLED=true
ENV KC_METRICS_ENABLED=true
...

~~~

It generates the following error:

_rror: initializing source docker://registry.redhat.io/rhbk/keycloak-rhel9:latest: reading manifest latest in registry.redhat.io/rhbk/keycloak-rhel9: unsupported: This repository does not use the "latest" tag to track the most recent image and must be pulled with an explicit version or image reference. For more information, see: https://access.redhat.com/articles/4301321_ 

~~~

podman build . -t localhost/keycloak/mykeycloak-debug:1.0
STEP 1/3: FROM registry.redhat.io/rhbk/keycloak-rhel9:latest AS builder
Trying to pull registry.redhat.io/rhbk/keycloak-rhel9:latest...
WARN[0000] Failed, retrying in 2s ... (1/3). Error: initializing source docker://registry.redhat.io/rhbk/keycloak-rhel9:latest: reading manifest latest in registry.redhat.io/rhbk/keycloak-rhel9: unsupported: This repository does not use the "latest" tag to track the most recent image and must be pulled with an explicit version or image reference. For more information, see: https://access.redhat.com/articles/4301321 

~~~

The way to fix it is to use the proper appropriate tag such as:

~~~

FROM registry.redhat.io/rhbk/keycloak-rhel9:22-7 as builder

....

.... 
["/opt/keycloak/bin/kc.sh"]

~~~