Use authServerUrl instead of authUrl to initialize Keycloak Admin Client

[thomasdarimont]

Describe the bug

If Keycloak is configured with a different admin-hostname (e.g. other than the frontend-hostname) for the admin-console, then the admin-console.v2 does not initialize correctly.

See: #12192

Version

18.0.0 / Main

Expected behavior

When using a dedicated admin-hostname then the admin-console.v2 should still work.

Actual behavior

Admin Console.V2 does not load correctly if different hostname settings are used.
See: #12192 (comment)

How to Reproduce?

• Checkout Allow setting the admin hostname #12192
• Build a keycloakx distribution
• Run keycloak with a dedicated admin and frontend hostname:

 bin/kc.sh --verbose \
  start \
  --auto-build \
  --hostname=id.acme.test \
  --hostname-port=8443 \
  --hostname-strict=true \
  --hostname-strict-https=true \
  --hostname-strict-backchannel=true \
  --hostname-admin=admin.acme.test \
  --http-enabled=true \
  --http-relative-path="auth" \
  --proxy=edge \
  --https-certificate-file=./acme.test+1.pem \
  --https-certificate-key-file=./acme.test+1-key.pem \
  --spi-events-listener-jboss-logging-success-level=info \
  --spi-events-listener-jboss-logging-error-level=warn \
  --features=admin2

Anything else?

There is another bug in Keycloak which is fixed in #12192, which currently prevents users to easily configure different hostnames for frontend and admin usage.

A fix for the admin-console.v2 bootstrap can be found here:
#12192 (comment)