Installing Docker on Ubuntu

This procedure works on both my laptop and a fresh EC2 instance.

Add the GPG key for Docker.

curl -fsSL https://download.docker.com/linux/$(. /etc/os-release; echo "$ID")/gpg | sudo apt-key add -

Add the details of the Docker repository.

OSNAME=$(. /etc/os-release; echo "$ID")
OSVERS=$(lsb_release -cs)
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/$OSNAME $OSVERS stable"

Update the package index.
```
sudo apt update
```
Install the Community Edition package.
```
sudo apt install docker-ce
```
Test it.
```
sudo docker run hello-world
```

The output from the test should look something like this:

Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
5b0f327be733: Pull complete 
Digest: sha256:1f1404e9ea1a6665e3664626c5d2cda76cf90a4df50cfee16aab1a78f58a3f95
Status: Downloaded newer image for hello-world:latest

Hello from Docker!
This message shows that your installation appears to be working correctly.

To generate this message, Docker took the following steps:
 1. The Docker client contacted the Docker daemon.
 2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
 3. The Docker daemon created a new container from that image which runs the
    executable that produces the output you are currently reading.
 4. The Docker daemon streamed that output to the Docker client, which sent it
    to your terminal.

To try something more ambitious, you can run an Ubuntu container with:
 $ docker run -it ubuntu bash

Share images, automate workflows, and more with a free Docker ID:
 https://cloud.docker.com/

For more examples and ideas, visit:
 https://docs.docker.com/engine/userguide/

Note that the docker command currently requires superuser privileges. To allow docker for mere mortals, add their accounts to the docker group.

sudo gpasswd -a ubuntu docker

On that user’s next login the docker group will be added to their profile and they will be able to launch docker jobs.

I’ve wrapped the installation up in a very simple Gist. You can source the gist and install using

$ wget -q -O - https://bit.ly/2JGrYR2 | /bin/bash