Issue: The keycloak container fails to start, after the upgrade of the Keycloak app.
In the keylcoak apps logs we see the message (univention-app logs keycloak)
2026-03-27 09:22:16,901 INFO [org.hibernate.orm.jdbc.batch] (JPA Startup Thread) HHH100501: Automatic JDBC statement batching enabled (maximum batch size 32)
2026-03-27 09:22:16,912 INFO [com.arjuna.ats.jbossatx] (main) ARJUNA032014: Stopping transaction recovery manager
ERROR: Failed to start server in (production) mode
ERROR: [PersistenceUnit: keycloak-default] Unable to build Hibernate SessionFactory
ERROR: Persistence unit 'keycloak-default' was configured to run with a database version of at least '10.6.0', but the actual version is '10.5.28'. Consider upgrading your database. Alternatively, rebuild your application with 'jakarta.persistence.database-product-version=10.5.28' (but this may disable some features and/or impact performance negatively).
The app is at version 26.5.6
Cause: The specific instance uses an external MariaDB server for persistence storage. This server is at version 10.5.28. Since the app version 26.4 keycloak has a requirement for the MariaDB version >=10.6.0.
Solution: We first need to find out what server keycloak tries to connect to. For this i enable the log level debug
univention-app configure keycloak --set keycloak/log/level=DEBUG
and then i can see in the apps logs
Setting kc/db/url to 'jdbc:mariadb://1.2.3.4:3306/keycloak'
This tells us that the mariadb server is reached under the IP 1.2.3.4. Now we can upgrade that system or at least the mariadb version.