How to Install Docker on Ubuntu 22.04

How to Install Docker on Ubuntu 22.04. Docker is a open-source platform that uses OS-level virtualization to deliver software in packages called containers. Container is a unit of software that packages up code and all its dependencies so the application runs quickly and reliably from one computing environment to another.

In this guide you are going to learn how to install Docker on Ubuntu 22.04 LTS. This setup is tested on Google Cloud Platform so it will work fine on any cloud servers or any VPS or any dedicated servers running Ubuntu 22.04.

Prerequisites

• SSH access to server with sudo privileges.

Initial Setup

Start by updating the packages to the latest version available.

sudo apt update
sudo apt upgrade

Step 1: Install Docker

Make sure you install the latest version of Docker from the official Docker repository. The official Ubuntu repository also has the Docker installation package, but it may not be the latest version.

Let’s start installing Docker.

Install some packages which allows you to use the packages over HTTPS.

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

Add the GPG key of Docker repository.

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg

Now add the Docker repository of Ubuntu 22.04 (jammy) to the apt sources.

echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

Update the packages index and setup your server to install Docker from official Docker repo.

sudo apt update
sudo apt-cache policy docker-ce

You will receive an output similar to this.

Output
docker-ce:
  Installed: (none)
  Candidate: 5:20.10.14~3-0~ubuntu-jammy
  Version table:
     5:20.10.14~3-0~ubuntu-jammy 500
        500 https://download.docker.com/linux/ubuntu jammy/stable amd64 Packages
     5:20.10.13~3-0~ubuntu-jammy 500
        500 https://download.docker.com/linux/ubuntu jammy/stable amd64 Packages

Now you can install Docker.

sudo apt install docker-ce

Once Docker is installed and the process is enabled to start on boot.

To check the status of Docker you can use the following command.

sudo systemctl status docker

The output will be like this.

Output
● docker.service - Docker Application Container Engine
     Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)
     Active: active (running) since Wed 2022-05-04 06:43:00 UTC; 2min 28s ago
TriggeredBy: ● docker.socket
       Docs: https://docs.docker.com
   Main PID: 12995 (dockerd)
      Tasks: 8
     Memory: 38.6M
        CPU: 400ms
     CGroup: /system.slice/docker.service
             └─12995 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock

Configure Sudo permissions for Docker

The docker command can only be executed as root user by default. If you need to run the docker command without sudo, you need to add your username to the docker group.

sudo usermod -aG docker username

Now restart your SSH or open a new terminal to see the changes.

From now you use the docker command without sudo.

Using Docker Commands

To view the system information about Docker.

docker info

Download Docker Images

docker run hello-world

If the output you get is similar to the below then you can access and download images from Docker Hub.

Output
Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
2db29710123e: Pull complete 
Digest: sha256:10d7d58d5ebd2a652f4d93fdd86da8f265f5318c6a73cc5b6a9798ff6d2b2e67
Status: Downloaded newer image for hello-world:latest

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

Run the below command to see downloaded images.

docker images

Docker Commands

Once you have started using Docker you will have many active and inactive containers.

To view all active containers, use the following command.

docker ps

To view all containers which are active and inactive, use the below command.

docker ps -a

To view the latest container

docker ps -l

To start a docker container, use docker start command followed by the Container ID or Container Name.

docker start container-id/name

Likewise to stop a running container you can use the docker stop command followed by Container ID or Container Name.

docker stop container-id/name

If you no longer need the container you can remove the container with the docker rm followed by Container ID or Container Name.

docker rm container-id/name

To enter into interactive shell you can use the following command.

docker run -it container-id/name

You can manually install commands inside the shell.

For more details about docker commands use the docker run help command.

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Conclusion

Now you have learned how to install and manage Docker on Ubuntu 22.04.

Thanks for your time. If you face any problem or any feedback, please leave a comment below.