Docker ImagesΒΆ

Show images

$ sudo docker images

Specifying a Variant

$ sudo docker run -t -i ubuntu:14.04 /bin/bash

Pull an Image

$ sudo docker pull debian

Create your own image

  1. Create a Dockerfile with the following content

    FROM debian:wheezy
    RUN apt-get update && apt-get install -y cowsay fortune
  2. Go to the directory container Dockerfile and execute the following command to build a image

    $ docker build -t test/cowsay-dockerfile .

    You will see output as shown below

    Sending build context to Docker daemon 2.048 kB
    Sending build context to Docker daemon
    Step 0 : FROM debian:wheezy
    wheezy: Pulling from debian
    7a3e804ed6c0: Pull complete
    b96d1548a24e: Already exists
    Status: Downloaded newer image for debian:wheezy
     ---> b96d1548a24e
    Step 1 : RUN apt-get update && apt-get install -y cowsay fortune
     ---> Running in 4404353a3643
    Get:1 wheezy/updates Release.gpg [1554 B]
    Get:2 wheezy/updates Release [102 kB]
    Get:3 wheezy Release.gpg [2390 B]
    Setting up perl (5.14.2-21+deb7u2) ...
    update-alternatives: using /usr/bin/prename to provide /usr/bin/rename
     ---> ca3618d10f2a
    Removing intermediate container 4404353a3643
    Successfully built ca3618d10f2a
  3. Check that image has been created

    $ docker images
    REPOSITORY                   TAG                 IMAGE ID            CREATED             VIRTUAL SIZE
    test/cowsay-dockerfile       latest              ca3618d10f2a        3 minutes ago       126.9 MB
    docker-dev                   dry-run-test-2      db155754d7fc        6 days ago          1.571 GB
    <none>                       <none>              b01392d005bb        6 days ago          1.571 GB
    debian                       wheezy              b96d1548a24e        7 days ago          84.97 MB
    debian                       latest              df2a0347c9d0        7 days ago          125.2 MB
    dockerswarm/dind-master      latest              bb4cd757411e        7 days ago          159 MB
    <none>                       <none>              f672d2db20f6        7 days ago          1.571 GB
    <none>                       <none>              1fe07c1fdf52        8 days ago          1.571 GB
    dockerswarm/swarm-test-env   latest              01e6a0da0825        2 weeks ago         515.5 MB
    ubuntu                       14.04               07f8e8c5e660        3 weeks ago         188.3 MB
    hello-world                  latest              91c95931e552        5 weeks ago         910 B
    busybox                      latest              8c2e06607696        5 weeks ago         2.433 MB
  4. Run the cowsay program using the built image

    $ docker run test/cowsay-dockerfile /usr/games/cowsay "Hi!"

    This will execute and show the output

    < Hi! >
            \   ^__^
             \  (oo)\_______
                (__)\       )\/\
                    ||----w |
                    ||     ||
  5. Removing a Docker Image : Docker image can be removed using the following command

    $ docker rmi test/cowsay-dockerfile