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Olga Christensen edited this page Oct 20, 2016 · 9 revisions

[Docker Explained: Using Dockerfiles to Automate Building of Images] (https://www.digitalocean.com/community/tutorials/docker-explained-using-dockerfiles-to-automate-building-of-images) @DigitalOcean

[Dockerfile reference] (https://docs.docker.com/engine/reference/builder/) @Docs.Docker

##Docker Machine

docker-machine ls

docker-machine Start/stop [NAME/S]

docker run hello-world

Run docker ps -a to show all containers on the system.

The command docker ps shows only currently running containers.

The command docker images lists all the images on your local system

You can specify a repository and tag at which to save the new image if the build succeeds:
$ docker build -t shykes/myapp .

# Stop ALL running containers
docker stop $(docker ps -a -q)

# Remove all build containers
docker rm $(docker ps -a -q)

# Remove all saved images (that is remove base images downloaded and cached)
docker rmi $(docker images -q)

##Build your own image

####Dockerfile

  1. Go to your command terminal window.
  2. Make a new directory by typing mkdir mydockerbuild and pressing RETURN.
    mkdir mydockerbuild
    This directory serves as the “context” for your build. The context just means it contains all the things you need to build your image.
  3. Change to your new directory.
    cd mydockerbuild Right now the directory is empty.
  4. Create a Dockerfile in the directory by typing touch Dockerfile and pressing RETURN.
    touch Dockerfile The command appears to do nothing but it actually creates the Dockerfile in the current directory.
  5. Open the Dockerfile in a visual text editor like Atom or Sublime, or a text based editor like vi, or nano (https://www.nano-editor.org/).
  6. Add a line to the file like this: FROM docker/whalesay:latest The FROM keyword tells Docker which image your image is based on. Whalesay is cute and has the cowsay program already, so we’ll start there.
  7. Now, add the fortunes program to the image.
    RUN apt-get -y update && apt-get install -y fortunes
    The fortunes program has a command that prints out wise sayings for our whale to say. So, the first step is to install it. This line installs the software into the image.
  8. Once the image has the software it needs, you instruct the software to run when the image is loaded.
    CMD /usr/games/fortune -a | cowsay
    This line tells the fortune program to pass a nifty quote to the cowsay program.
  9. Check your work, your file should look like this:
    FROM docker/whalesay:latest RUN apt-get -y update && apt-get install -y fortunes CMD /usr/games/fortune -a | cowsay
  10. Save and close your Dockerfile.
    At this point, you have all your software ingredients and behaviors described in a Dockerfile. You are ready to build a new image.

####Build image from Dockerfile

  1. At the command line, make sure the Dockerfile is in the current directory by typing cat Dockerfile
  2. Now, build your new image by typing docker build -t docker-whale .

##Run interactive container

docker run -t -i ubuntu /bin/bash

docker run runs a container.
ubuntu is the image you would like to run.
-t flag assigns a pseudo-tty or terminal inside the new container.
-i flag allows you to make an interactive connection by grabbing the standard in (STDIN) of the container.
/bin/bash launches a Bash shell inside our container.
exit command or Ctrl-D to exit the interactive shell.

##Troubleshooting

[@Docks.Docker.com] (https://docs.docker.com/toolbox/faqs/troubleshoot/)

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