How To Install and Use Docker on Ubuntu 16.04/18.04/Aws Ec2


Docker is an open-source containerization tool that allows you to easily build, test, and deploy applications. Docker helps to package an application with all parts (code, logs, libraries, configuration settings, and other dependencies) and allows them to run as isolated containers. Containers are lighter weight, portable.self-sufficient, and easier to manage.

Docker software is maintained by the Docker community and Docker Inc.To learn more about Docker concepts and docs checkout official documentation.

In this tutorial, we’ll learn how to install Docker Community Edition (CE) on on an Ubuntu 18.04 Aws ec2 instance.You can apply this same on local ubuntu or server also.

Before We Begin

  • Ubuntu 18.04 system with root or user with sudo privileges

Step-1:Install Docker

There are two ways to install Docker on ubuntu. One way is we can install docker from official Ubuntu repositories using apt, but the version may not be the latest. The recommended way is to install the latest Docker Package from the official Docker repository.

To do that, we have to add a new package source, add the GPG key from Docker to ensure that the downloads are valid, and then we will install the package.

At first update the ubuntu existing packages:

sudo apt update

Next, we will install a few prerequisite dependencies to add new packages over HTTPS:

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

Then we have to add the GPG key for the official Docker repository to our system:

curl -fsSL | sudo apt-key add -

Add the Docker repository to our system APT sources:

sudo add-apt-repository "deb [arch=amd64] bionic stable"

Next, update the package database with the Docker packages from our newly added repo:

sudo apt update

We have to make sure installing from the Docker repo instead of the default Ubuntu repo.So check by running:

apt-cache policy docker-ce

You’ll see output like this, although the version number for Docker may be different:

Installed: (none)
Candidate: 5:19.03.12~3-0~ubuntu-bionic
Version table:
5:19.03.12~3-0~ubuntu-bionic 500
500 bionic/stable amd64 Packages

Note that docker-ce is not installed.But installation candidate from Docker repository for Ubuntu bionic.

If we need to install a specific version, first list the available versions in the Docker repository:

apt list -a docker-ce

The command prints the available Docker versions in the second column.

For example, to install version 18.09.6 you would type:

sudo apt install docker-ce=5:18.09.8~3-0~ubuntu-bionic

We will install the latest version 5:19.03.12~3-0 shown from the above command not specifying specific version:

sudo apt install docker-ce

Now Docker is installed in our server. After installation automatically daemon started, and the process enabled us to start on boot.

Check Docker Status

We can check the docker status :

sudo systemctl status docker 

The output should be similar to the following, showing that the service is active and running:

● docker.service – Docker Application Container Engine
Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)
Active: active (running) since Sat 2020-07-18 07:45:17 UTC; 8min ago
Main PID: 3525 (dockerd)
Tasks: 8
CGroup: /system.slice/docker.service
└─3525 /usr/bin/dockerd -H fd:// –containerd=/run/containerd/containerd.sock

To check Docker version Installed :

docker -v
Docker version 19.03.12, build 48a66213fe

We can stop docker service as :

sudo systemctl stop docker 

To start/restart the service:

sudo systemctl start docker
sudo systemctl restart docker

Executing the Docker Command Without Sudo

By default, after docker installation,the docker command can only be run the root user or by a user in the docker group, which is automatically created during Docker’s package installtion. If you try to run the docker command without prefixing it with sudo or without being in the docker group, you’ll get an output like this:

docker images
Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Get http://%2Fvar%2Frun%2Fdocker.sock/v1.40/images/json: dial unix /var/run/docker.sock: connect: permission denied

To fix this ,add the user to docker group :

sudo usermod -aG docker $USER

Logout from the system and log back again to reflect the changes we made.

Now check again docker command without using sudo

ubuntu@ip-172-31-63-145:~$ docker images

To test a docker container run:

docker container run hello-world

The command will download a test image, run it in a container, print a “Hello from Docker” message and exit. The output should look like the following:

On upcoming posts we will learn more about Docker images and Docker containers working with best practices

Use Docker Commands

The Docker CLI command takes this form:

docker [option] [subcommand] [arguments]

To view all available subcommands, just type docker without no parameters as below :


It will list all available subcommands .In ubuntu 18.04 we can see output as below

To view the options available to a specific command, type:

docker docker-subcommand --help

For example If we run

docker ps --help  

It will list options showing how to use that particular sub-command “ps”.


In this tutorial, we learned to install Docker on ubuntu 18.04 and some basic commands to manage docker. It is just the starting. In upcoming Docker tutorials, we will learn about Docker images, Docker containers, Docker Compose, and Docker Swarm. To learn more about Docker check out the official Docker documentation

If you have any questions, please leave a comment below.

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