The user manual for APEX in readthedocs has some issues and inaccuracies in it:
https://onap.readthedocs.io/en/latest/submodules/policy/parent.git/docs/apex/APEX-User-Manual.html

• the docker profile should be sued to build the tarball
• the apex engine should be run using "sudo su"
• the APEX_HOME and APEX_USER environment variables should then be set
• debugging defaults to "debug" level rather than "info" level