It is not possible to build HA-CEP Spring boot image becuase microdnf fails with following error:
"The command '/bin/sh -c microdnf install --nodocs java-1.8.0-openjdk-headless && microdnf clean all' returned a non-zero code: 141"

It is probably related with this issue reported in microdnf: https://github.com/rpm-software-management/microdnf/issues/50

There are probably two possible solutions:

• Downgrade image to tag 8.0. For example as in this commit: https://github.com/submariner-io/submariner/pull/203/files
• Remove parameter --nodocs from microdnf command as is described here: https://github.com/rpm-software-management/microdnf/issues/50#issuecomment-550212377

I would suggest to go with the second option, because image with docs is only about 15MB bigger and we do not loose access to last updates.