How to Install Docker on an Ubuntu 20.04 VPS?

Hey fellow developer! Want to deploy your awesome project using Docker, and you already have an Ubuntu 20.04 VPS ready? Great! This guide is your bible for Docker installation, written by someone who’s been there and done that. No boring theory here – just practical steps, real commands, and a dash of my personal experience seasoned with developer humor. Get ready for easy and fast deployment! Let’s go!

• System Preparation
• Installing Docker Engine
• Verifying the Installation
• Working with Images
• Creating and Running a Container
• Additional Recommendations

System Preparation

Okay, so the first thing we need to do is update the system. You know, I’ve wasted countless hours debugging because I forgot to update packages… Don’t repeat my mistakes! Trust me on this one. Open your terminal and type:

sudo apt update && sudo apt upgrade -y

This command will update the package list and install all available updates. The `-y` flag is a shortcut to avoid answering «Continue?» for every question. Convenient, but be careful, *always backup before you mess with production!*

Next, we need to install the necessary dependencies. This is like preparing the foundation for building a house – you can’t build without it. Here are the commands:

sudo apt install apt-transport-https ca-certificates curl gnupg lsb-release -y

These packages are needed for secure downloading and installation of Docker. If something goes wrong – `sudo apt —fix-broken install` is your friend. This command will attempt to fix broken packages. Been there, done that…

And the final step before installing Docker is a reboot. Sounds trivial, but sometimes nothing works without it. You know, this part always trips people up. Just reboot the server:

sudo reboot

Installing Docker Engine

Now that the system is prepared, it’s time to install the Docker Engine itself. This is the heart of the whole process. First, add the Docker GPG key:

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

This command downloads and installs the Docker signature key. It’s important to make sure the URL is correct – you don’t want to accidentally install something malicious…

Then add the Docker repository:

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

This command adds the Docker repository to the list of package sources. Now the system will know where to look for Docker packages.

Finally, install the Docker Engine:

sudo apt update && sudo apt install docker-ce docker-ce-cli containerd.io docker-compose-plugin -y

Boom! That’s it! If everything went smoothly, the Docker Engine is installed. But… there’s one small detail… you need to add your user to the `docker` group to run Docker commands without `sudo`.

sudo usermod -aG docker $USER && newgrp docker

Don’t forget to reload your terminal or session for the changes to take effect. Seriously though, this part is important!

Verifying the Installation

Let’s check if everything is working as expected. The easiest way is to check the Docker version:

docker version

If the command returned Docker version information, everything is great! Congratulations! If not… check the logs: `journalctl -u docker` and `systemctl status docker`. Sometimes error messages aren’t very informative, but *reading logs is a superpower*. Learn to use them!

Another test – let’s run a simple container. For example, hello-world:

docker run hello-world

If everything is fine, you’ll see a message about the successful container launch. If not – check the logs again! And don’t forget to check your firewall rules!

At this stage, if all commands were successfully executed and `docker run hello-world` worked without errors, congratulations! You have Docker installed and running. You did it!

Working with Images

Now that Docker is installed, it’s time to learn how to work with images. Images are like blueprints for containers. First, let’s download the nginx image:

docker pull nginx

This command will download the nginx image from Docker Hub. Docker Hub is a massive repository of images for various applications. It’s like a huge App Store for containers. Think of it as a giant Lego brick store.

Let’s check if the image was downloaded:

docker images

You should see nginx in the list of images. If not – double-check the `docker pull nginx` command and make sure your internet connection is working correctly. Ugh, this part always trips people up.

You can also search for images: `docker search nginx`

To remove an image, use the command `docker rmi <image_id>`, replacing <image_id> with the image ID. Be careful! *Always double check the image ID before removing*.

Creating and Running a Container

Now let’s run a container based on the nginx image. Here’s the command:

docker run -d -p 8080:80 --name my-nginx nginx

Let’s break down what’s happening here: `-d` runs the container in the background, `-p 8080:80` redirects port 80 of the container to port 8080 of the host, `—name my-nginx` gives a name to the container, `nginx` is the image name. It hits different, when you understand all the flags.

Let’s check if the container is running:

docker ps

You should see your `my-nginx` container in the list. If not – check the logs again! And check that port 8080 is free.

Open your browser and go to `http://your_server_ip:8080`. If you see the standard nginx page, then hooray, the container is working!

To stop the container use `docker stop my-nginx`, and to remove it use `docker rm my-nginx`.

Additional Recommendations

Here are a few tips to help you avoid headaches in the future. Real talk… Docker is a powerful tool, but without proper care it can become a source of problems.

• Use Docker Compose to manage multiple containers. This will simplify deployment and management.
• Regularly update the Docker Engine and images. This will improve security and performance.
• Create Dockerfiles to automate image building. This will save you a lot of time and nerves.
• Learn how to work with Docker volumes to store container data. This will allow you to preserve data even after deleting the container.
• Configure Docker to work with remote repositories, such as Docker Hub or private registries.

Here’s another link to Stack Overflow, just in case. No cap, you can find answers to almost any Docker question there. And don’t forget the official documentation!

“Docker simplifies the lives of developers, allowing them to easily create, deploy, and scale applications.”

Unknown Docker Expert

“Using Docker significantly reduces application deployment time and improves their reliability.”

Another unknown expert

And remember: practice is the best way to master Docker. Experiment, don’t be afraid of mistakes, and you’ll quickly become a Docker guru! Good luck!