How to enter in a Docker container already running with a new TTY

Question

I have a container that is running the Apache service in the foreground. I would like to be able to access the container from another shell in order to \"poke around\" insid

Answer 1

Update

As of docker 0.9, for the steps below to now work, one now has to update the /etc/default/docker file with the '-e lxc' to the docker daemon startup option before restarting the daemon (I did this by rebooting the host).

This is all because...

...it [docker 0.9] contains a new "engine driver" abstraction to make possible the use of other API than LXC to start containers. It also provide a new engine driver based on a new API library (libcontainer) which is able to handle Control Groups without using LXC tools. The main issue is that if you are relying on lxc-attach to perform actions on your container, like starting a shell inside the container, which is insanely useful for developpment environment...

source

Please note that this will prevent the new host only networking optional feature of docker 0.11 from "working" and you will only see the loopback interface. bug report

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It turns out that the solution to a different question was also the solution to this one:

...you can use docker ps -notrunc to get the full lxc container ID and then use lxc-attach -n run bash in that container as root.

Update: You will soon need to use ps --no-trunc instead of ps -notrunc which is being deprecated.

Find the full container ID

Enter the lxc attach command.

Top shows my apache process running that docker started.