How do I get into a Docker container's shell?

Question

I'm getting started working with Docker. I'm using the WordPress base image and docker-compose.

I'm trying to ssh into one of the containers to inspect the files/directories that were created during the initial build. I tried to run docker-compose run containername ls -la, but that didn't do anything. Even if it did, I'd rather have a console where I can traverse the directory structure, rather than run a single command. What is the right way to do this with Docker?

Answer 1

To bash into a running container, type this:

docker exec -t -i container_name /bin/bash 

or

docker exec -ti container_name /bin/bash 

or

docker exec -ti container_name sh 

Answer 2

docker attach will let you connect to your Docker container, but this isn't really the same thing as ssh. If your container is running a webserver, for example, docker attach will probably connect you to the stdout of the web server process. It won't necessarily give you a shell.

The docker exec command is probably what you are looking for; this will let you run arbitrary commands inside an existing container. For example:

docker exec -it <mycontainer> bash 

Of course, whatever command you are running must exist in the container filesystem.

In the above command <mycontainer> is the name or ID of the target container. It doesn't matter whether or not you're using docker compose; just run docker ps and use either the ID (a hexadecimal string displayed in the first column) or the name (displayed in the final column). E.g., given:

$ docker ps d2d4a89aaee9        larsks/mini-httpd   "mini_httpd -d /cont   7 days ago          Up 7 days                               web                  

I can run:

$ docker exec -it web ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN      link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00     inet 127.0.0.1/8 scope host lo        valid_lft forever preferred_lft forever     inet6 ::1/128 scope host         valid_lft forever preferred_lft forever 18: eth0: <BROADCAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP      link/ether 02:42:ac:11:00:03 brd ff:ff:ff:ff:ff:ff     inet 172.17.0.3/16 scope global eth0        valid_lft forever preferred_lft forever     inet6 fe80::42:acff:fe11:3/64 scope link         valid_lft forever preferred_lft forever 

I could accomplish the same thing by running:

$ docker exec -it d2d4a89aaee9 ip addr 

Similarly, I could start a shell in the container;

$ docker exec -it web sh / # echo This is inside the container. This is inside the container. / # exit $