Well, how I would dive into this issue.

  1. Run %SYS.MONLBL in production, for a relevant time gap, at least 1 hour. You can filter it by classes which you care, and get the only line counts, to decrease impact on speed.
  2. So, you can collect summary time for all such Methods.
  3. Change a few of them to the new way as a ClassMethod, from MONLBL you can find the list of frequently used ones. So, will be easy to find what to change.
  4. Run %SYS.MONLBL with the same conditions as in the first time.
  5. Compare results.
  6. Decide

Of course, this way not so easy to realize, and depends on how you deploy code in production. Or maybe it even possible to measure in the testing environment.

This behaviour expected if you use default Docker configuration, look at mention about aufs above in comments.

But, you should use docker version 18.06, because  in newest version already deleted support for AUFS, and InterSystems does not work on overlay driver wchich is used by default in Docker.

when your container run, and you can find it in running state, you can use command

docker ps -a

which will show all existing containers in any state.

and then you can look at the logs of particular container

docker logs `hash shown after run command or assigined name visible in docker ps -a`

looks like you did some changes in your Dockerfile comparing to my example, and you did mistake there. Can you share your Dockerfile, so I could check it?

In my example I have line

ADD $cache-lnxrhx64.tar.gz .

where $cache is variable defined few lines above. And when build will run, it will be replaced with value. But in your case, I see $ensemble, and sure that you don't have such variable, and this follows to the error.

I have configured automatic deployment of the application to Kubernetes with Helm from GitLab as a part of CI/CD process.

I would not say that I had some specific issues, just well configured Kubernetes cluster with the right storage driver. Any InterSystems products supports devicemapper and aufs right now, yet. So, of course, better to have devicemapper available server, and use this possibility. AUFS already deprecated by Docker and will disappear in the next major release.