Container Control Commands

Downloading Containers #

For example, to download an nginx container, you can write it as follows. The latest tag fetches the most recent version of the container image.

# docker pull NAME[:TAG]
$ docker pull nginx:latest

Running Containers #

Running containers typically uses the docker run command and has the following format. If you want to run an ubuntu:16.04 container, you can do so as follows.

# docker run [OPTION] IMAGE[:TAG] [COMMAND]
$ docker run -i -t ubuntu:16.04 /bin/bash

Running in Foreground #

The -t option allocates a TTY, and the -i option uses standard input/output. For example, you can create an Ubuntu 16.04 container with the -i and -t options and run its default command, /bin/bash. The same behavior is expected even if this command is not explicitly entered.

$ docker run -i -t ubuntu:16.04 bin/bash

Running as a Daemon (Detached) #

Run as a daemon using the -d option. Web server containers, among others, are typically run in this mode. For example, run an nginx container.

$ docker run -d -p 80:80 nginx

Assigning Container Names #

To manage containers via commands, assign a name using the --name option. If you don't specify a name, a random one will be assigned, but it can be difficult to manage, so be careful.

$ docker run -i -t --name my_ubuntu ubuntu:16.04 /bin/bash

Container Port Forwarding #

When creating, use the -p option. In the daemon execution example above, port 80 was exposed for the nginx container; to expose multiple ports, you can use multiple -p options.

$ docker run -d --name my_nginx -p 80:80 =p 3306:3306 nginx:latest

Stopping & Exiting Containers #

Input is typically done via the terminal within the container, and there are two ways: exit and Ctrl + P, Q. The exit command completely stops the container. The Ctrl + P, Q command leaves the container's current state as is and only detaches your connection.

# Stop
$ exit

If you want to switch the container to the background without stopping it, press Ctrl and then P and Q sequentially to exit.

# Exit
$ Ctrl + P,Q