Docker

Overview

What is Docker

Docker is a way of deploying apps on servers. It packages apps into side-by-side containers. These are similar in spirit to virtual machines, but different because containers are not (or, don't have to be) fully bundled operating systems. The container system makes sure everything runs the same everywhere.

It's like Homebrew or Aptitude for apps.

Installing

Docker has great documentation on getting up and running: https://docs.docker.com/

Docker also provides several examples of docker-izing an app: https://docs.docker.com/engine/examples/

Linux

You can get docker running on many virtual hosting services.

Linode supports docker: https://blog.linode.com/2014/01/03/docker-on-linode/

They offer installation guides for different distributions: https://docs.docker.com/engine/installation/linux/#install-using-the-repository

Ubuntu

Guide to installing Docker on Ubuntu Linux: https://docs.docker.com/engine/installation/linux/ubuntulinux/

Start by setting up Docker's repositories:

$ sudo apt-get install \
    apt-transport-https \
    ca-certificates \
    curl \
    software-properties-common

Add Docker's GPG key:

$ curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -

Verify fingerprint starts with 9DC8:

$ sudo apt-key fingerprint 0EBFCD88

Set up the stable repository:

$ sudo add-apt-repository \
   "deb [arch=amd64] https://download.docker.com/linux/ubuntu \
   $(lsb_release -cs) \
   stable"

Install docker by updating package index and running install:

$ sudo apt-get update
$ sudo apt-get install docker-ce

Test it out:

$ sudo docker run hello-world

Errors

When I added Docker's repos to my aptitude following the instructions above, I kept seeing 403 errors from docker's repo when I ran apt-get update:

sudo apt-get update
...
W: Failed to fetch https://download.docker.com/linux/ubuntu/dists/wily/stable/binary-amd64/Packages  HttpError403

Resolving

Resolved the problem by downloading the right package myself.

Start with the name of your release:

$ lsb_release -c
Codename:                     wily

Now navigate to their aptitude repositories in your browser: https://apt.dockerproject.org/repo/pool/main/d/docker-engine/

Find the deb file that corresponds to your install and copy the link.

$ wget <link to .deb file> 

Now you can install it (you probably need to be sudo):

$ dpkg -i docker-engine_1.9.1-0~wily_amd64.deb
Selecting previously unselected package docker-engine.
(Reading database ... 142272 files and directories currently installed.)
Preparing to unpack docker-engine_1.9.1-0~wily_amd64.deb ...
Unpacking docker-engine (1.9.1-0~wily) ...
Setting up docker-engine (1.9.1-0~wily) ...
Processing triggers for ureadahead (0.100.0-19) ...
Processing triggers for systemd (225-1ubuntu9.1) ...
Processing triggers for man-db (2.7.4-1) ...

Mac

You can run docker on Mac: https://docs.docker.com/docker-for-mac/