Exploring Docker container's file system?

Question

I've noticed with docker that I need to understand what's happening inside a container or what files exist in there. One example is downloading images from the docker index - you don't have a clue what the image contains so it's impossible to start the application. What would be ideal is to be able to ssh into them or equivalent. Is there a tool to do this, or is my conceptualisation of docker wrong in thinking I should be able to do this.

Answer 1

Docker allows you to run commands within a container using the "docker exec" command. Therefore you can run a "docker exec -it My_Container_or_ID_Hash /bin/bash" command to get into the Bash command line within the container. From there, you will be able to utilize the tools within the container to explore all you want.

This only works with containers that have a continuous run - like a web server or DB server. If the container runs a command then exits (stops), you won't be able to use that command. Think of these as a container that runs a script or command that would typically put you back at the command prompt.

Just think of a container as a virtual machine with the bare minimum needed to run the code that the container was built for.