SSSD seems to work now and I can login to Keycloak with an IPA user. Unfortunately, when trying to use an AD user I get an exception:
Aug 20 13:10:46 keycloak-test.linux.mydomain.at standalone.sh[16537]: 13:10:46,967 WARN [org.keycloak.services] (default task-52) KC-SERVICES0013: Failed authentication: org.keycloak
.federation.sssd.api.SSSDException: Failed to retrieve user's attributes. Check if SSSD service is active.
Aug 20 13:10:46 keycloak-test.linux.mydomain.at standalone.sh[16537]: at org.keycloak.federation.sssd.api.Sssd.getUser(Sssd.java:112)
Aug 20 13:10:46 keycloak-test.linux.mydomain.at standalone.sh[16537]: at org.keycloak.federation.sssd.SSSDFederationProvider.importUserToKeycloak(SSSDFederationProvider.java:114)
Aug 20 13:10:46 keycloak-test.linux.mydomain.at standalone.sh[16537]: at org.keycloak.federation.sssd.SSSDFederationProvider.findOrCreateAuthenticatedUser(SSSDFederationProvider.java:
109)
SSSD service is active.