Docker has a number of nifty options to help investigate containers
and container images. One option I have used over and over to debug
issues is the docker [“diff” command.]
(https://docs.docker.com/engine/reference/commandline/diff/)
This dumps out the files that have been aded (A), deleted (D)
and created(C) since the container started. Here’s a simple
example showing diff in action:
$ docker run --rm -it --name centos centos bash
$ touch /tmp/bar /tmp/baz /tmp/foo
$ docker diff centos
C /run
D /run/secrets
C /tmp
A /tmp/bar
A /tmp/baz
A /tmp/foo
Cool stuff!