Root login for debugging docker containers

[dynamodan]

Is your feature request related to a problem? Please describe.
Would like to be able to debug the processes that are running inside of docker containers, specifically more detailed debugging about synapse and MAS.

Describe the solution you'd like
docker exec -it 0c12349a0c98 /bin/bash

Instead, I get:
OCI runtime exec failed: exec failed: unable to start container process: exec: "/bin/bash": stat /bin/bash: no such file or directory

Describe alternatives you've considered
There could also be standard syslogging coming out to a location like /var/log/matrix-synapse.log. There isn't, and I'm not sure how to configure it with docker.

Additional context
All I was doing was trying to debug while setting up. Ansible and Docker are nice, they do abstract away a lot of detail, but sometimes it's too much abstraction and we need to peek under the hood.

[spantaleev]

journalctl -fu matrix-synapse, etc. We use systemd-journald for logging.

We use official container images where possible. Some are based on Alpine, so there's no /bin/bash, but there is /bin/sh.