I don't recall starting this container:
IMAGE COMMAND CREATED STATUS
google/cadvisor:latest "/usr/bin/cadvisor -l" 2 days ago Exited (0) 2 days ago
which has now exited. Any idea whether it's a good idea to do a docker rm
on it?
E.g. is it being used by Docker or Google somewhere for monitoring?
cAdvisor (short for "container advisor") is a project by Google that collects monitoring data from your Docker Engine, e.g. number of running containers, ressource usage per container and so on.
If you do not recall starting this container yourself, it is possible that some other application has started it. While I am not aware of any application that does this without asking, I could very well imagine that you are running a management application that uses cAdvisor for monitoring other containers on the host.
It is certainly not part of Docker itself, but as it is stopped there should be no harm in removing it.