September 2017

Docker Notes

• A Dockerfile can consist of a single line: FROM ubuntu
• To build the image from a Dockerfile in the current directory: docker build .
• To run an image: docker run --rm -it ccc7a1, where ccc7a1 is any part of the hash for a given image (list the available images with docker images)
• Example: docker run --rm -it python:3.6
  • --rm means destroy when done
  • -it means interactive with terminal attached
  • We could do -d to run in background
• Some images available: library/fedora, alpine (small Linux)
• Sign up for a docker id on their website
• Portainer can be used to get a Web interface to your local Docker images
• Portainer instructs you to use the following command: docker run -d -p 9000:9000 -v /var/run/docker.sock:/var/run/docker.sock portainer/portainer
  • -v allows file in
• You can run the basic Docker Hello World with docker --rm -it hello-world
  • If you don't do the slash with hello-world, then it goes to the library online.
• To exit Docker container: exit
• docker ps (see what's running)
• docker pull hello-world (no slash - library/, it's what Docker people themselves maintain)
• Adds :latest if you don't do a version number (meaning e.g. :14.04 for Ubuntu Trusty)
• docker ps -a (see what you already ran)
• docker images (show images)
• docker rmi 05a3 (remove image, can use any part of the hash)
• When we do run, it creates a container from the image.
• docker logs

Dockerfile: a script that lets you build an image or container or whatever.

FROM ubuntu:14.04

then: docker build . or docker build -f MyDockerfile .

Dockerfile is executed every time you build the image.