Docker Entrance

Sometimes I need to troubleshoot running containers or spin up an image then check on something that got built. These are the simple commands I run to ensure that I can get into the container or image, check what I need to do and get out.

Container Entrance (easy)

Lets say you have an container that you want to see what is on it, you should be able to spin it up and enter into a command line interface. Run the following to get into it:

docker exec --interactive --tty <mycontainer> bash

This can be simplified to docker exec -it <mycontainer> bash.

⚠️ You may have to identify where the bash command is depending, or even use a more basic sh shell command

Image Entrance (less straight forward)

What you need to do with this is allow the image to start up then enter into the container, this can be done in the following command:

docker run --rm -it --entrypoint /bin/bash image_name

This is a little bit more harder to ensure it works properly. There are a number of issues that may occur based upon the way the container is set up to run the image, so please watch out.

Container Entrance Using Attach

Another method to enter a running container is by using the docker attach command. This command allows you to attach your terminal’s standard input, output, and error to a running container.

docker attach <mycontainer>

⚠️ Be cautious when using docker attach as it connects to the main process of the container. If the main process terminates, the container will stop.