A Simple Guide to Installing Docker CE on Ubuntu

September 2, 2018

What You Need Before You Begin #

Operating System Requirements #

First things first, make sure you’re running one of the following 64-bit Ubuntu versions to install Docker CE:

Ubuntu 18.04 (Bionic) - LTS
Ubuntu 17.10 (Artful)
Ubuntu 16.04 (Xenial) - LTS
Ubuntu 14.04 (Trusty) - LTS

Docker CE is compatible with these architectures: x86_64, armhf, s390x (IBM Z), and ppc64le (IBM Power).

Note: For IBM Z and Power architectures, you’ll need at least Ubuntu 16.04 (Xenial) or higher.

Out with the Old #

If you’ve had older versions of Docker installed, it’s a good idea to get rid of them first:

sudo apt-get remove docker docker-engine docker.io

Don’t worry if apt-get says that none of these packages exist. It’s fine. Your old files in /var/lib/docker/, such as images and containers, won’t be deleted.

Storage Driver Info #

Docker CE supports overlay2 and aufs storage drivers on Ubuntu.

For Linux kernel version 4 or higher, overlay2 is the recommended choice.
If you’re on Linux kernel version 3, go with aufs.

If you need to use aufs, there’s some additional setup, but we won’t get into that here.

Let’s Install Docker CE #

Step-by-Step: Using a Repository #

Before you can enjoy the perks of Docker CE, you have to set up its repository. Once that’s done, you can easily install or update Docker.

Setting Up the Docker Repository #

Update your package list:
```
sudo apt-get update
```

Install some required packages:

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

Add Docker’s GPG key for secure downloads:
```
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
```
Check if the key has the fingerprint 9DC8 5822 9FC7 DD38 854A E2D8 8D81 803C 0EBF CD88:
```
sudo apt-key fingerprint 0EBFCD88
```
Finally, add the Docker repository:
```
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
```
Note: If you’re adventurous and want to try the edge or test versions, you can add them to the repository command above.

Time to Install Docker CE #

Refresh your package list again:
```
sudo apt-get update
```
Install Docker CE:
```
sudo apt-get install docker-ce
```
If you want a specific version, first list the available ones:
```
apt-cache madison docker-ce
```
Then install the version you want:
```
sudo apt-get install docker-ce=<VERSION>
```
Test your installation by running:
```
sudo docker run hello-world
```

Docker CE should now be up and running on your machine. Initially, you’ll need to use sudo for Docker commands. To enable non-root access, check out further Linux post-install steps.