docker-basics.md

Docker Basics

Table of Contents

• Containers
• Images

Containers

List running containers

docker ps

List all containers

docker ps -a

Run a container (the image will be downloaded if not yet so)

Start a container using the image nginx with host port 8080 mapped to container port 80 and name it try_nginx:

docker run --name try_nginx -p 8080:80 nginx

Start a container using the image ubuntu and name it try_ubuntu (nothing happens since no command is given):

docker run --name try_ubuntu ubuntu

Run a container in background

Start a container in the background using the image nginx with host port 8080 mapped to container port 80 and name it try_nginx:

docker run -d --name try_nginx -p 8080:80 nginx

-d, --detach: Run container in background and print container ID

Run a one-time command

Start a container using the image ubuntu, and delete it after the command echo finishes:

docker run --rm ubuntu echo "Hello World"

--rm: Automatically remove the container when it exits

Run a container, override the entry point command

Start a container using the image nginx, start an interactive shell instead of running the HTTP server:

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

--rm: Automatically remove the container when it exits

-i, --interactive: Keep STDIN open even if not attached

-t, --tty: Allocate a pseudo-TTY

--entrypoint string: Overwrite the default ENTRYPOINT of the image

Start an interactive shell in a running container

Start an interactive shell in the running container try_nginx:

docker exec -it try_nginx /bin/bash

Run a command in a running container

Run the ps command in the running container try_nginx:

docker exec try_nginx ps

Start a stopped (an existing) container

Start the container try_nginx:

docker start try_nginx

Stop a running container

Stop the container ac6aa090558c:

docker stop ac6aa090558c

Remove a container

Remove the container try_ubuntu:

docker rm try_ubuntu

Images

List downloaded images

docker images

Alternative spelling:

docker image ls

Download (or update) an image

Download (or update) the image ubuntu:

docker pull ubuntu

Download (or update) a specific tag of an image

Download (or update) the trusty tag of the image ubuntu:

docker pull ubuntu:trusty

Get a list of supported tags

HTML result:

https://hub.docker.com/_/ubuntu/

JSON result:

https://registry.hub.docker.com/v1/repositories/ubuntu/tags

Remove an image

Remove the image ubuntu:

docker rmi ubuntu

Alternative spelling:

docker image rm ubuntu