Docker overview

Docker is an open platform for developing, shipping, and running applications. Docker enables you to separate your applications from your infrastructure so you can deliver software quickly. With Docker, you can manage your infrastructure in the same ways you manage your applications. By taking advantage of Docker's methodologies for shipping, testing, and deploying code, you can significantly reduce the delay between writing code and running it in production.

Install Docker

Update the package repository

sudo apt update

Install the prerequisite packages

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

Add the Docker GPG key

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

Add the Docker repository to APT sources

sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu focal stable"

Update the package repository again

sudo apt update

Install Docker

sudo apt install docker-ce

Start and enable the Docker service

sudo systemctl start docker
sudo systemctl enable docker

This code adds the Docker repository to your system, installs Docker from the repository, and then starts and enables the Docker service so that it starts automatically when your system boots.

To verify that Docker is installed and running, you can use the following command:

sudo systemctl status docker

You should see output similar to the following, indicating that the Docker 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 Tue 2022-11-08 12:34:47 UTC; 1s ago
     Docs: https://docs.docker.com
 Main PID: 1118 (dockerd)
    Tasks: 5
   Memory: 43.7M
   CGroup: /system.slice/docker.service
           └─1118 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock

You can also use the docker command to verify that it is installed and working correctly. For example, you can run the following command to download and run the hello-world Docker image:

docker run hello-world

This should download the hello-world image and run a container using that image, which will display a message and then exit. If this command completes successfully, it indicates that Docker is installed and working correctly on your system.

You can also install Docker with a different command

or Install Docker

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

sudo apt-get update
sudo apt-get install \
ca-certificates \
curl \
gnupg

sudo install -m 0755 -d /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
sudo chmod a+r /etc/apt/keyrings/docker.gpg

echo \
"deb [arch="$(dpkg --print-architecture)" signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu \
"$(. /etc/os-release && echo "$VERSION_CODENAME")" stable" | \
sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
sudo apt update && apt upgrade -y

sudo apt-get install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin