ASSERT: make sure you have an application with 1 embedded cartridge (ex. mysql embedded) EXEC: in the OpenShift Explorer : pick your app and choose Edit Embedded Cartridges EXEC: uncheck the embedded cartridge that's currently added to your app and check a different 1 - 1 addition, 1 removal (ex. uncheck mysql , check postgres Result: The embedded cartridge you unchecked was not removed. If you did this with postgres/mysql then you'll get an error that tells you that only 1 database at the time is permitted.