How To Install and Use Docker on Ubuntu

Introduction

Docker is an application that simplifies the process of managing application processes in containers. Containers let you run your applications in resource-isolated processes. They’re similar to virtual machines, but containers are more portable, more resource-friendly, and more dependent on the host operating system.

For a detailed introduction to the different components of a Docker container, check out The Docker Ecosystem: An Introduction to Common Components.

In this tutorial, you’ll install and use Docker Community Edition (CE) on Ubuntu. You’ll install Docker itself, work with containers and images, and push an image to a Docker Repository. If you’re using Ubuntu 22.04, you can follow our guide on How To Install and Use Docker on Ubuntu 22.04 instead.

Note

This article will walk you through installing Docker on an Ubuntu server. If you wanted a 1-click way to deploy a Docker application to a live server, take a look at DigitalOcean App Platform.

Prerequisites

To follow this tutorial, you will need the following:

• One Ubuntu server set up by following the Ubuntu initial server setup guide, including a sudo non-root user and a firewall.
• An account on Docker Hub if you wish to create your own images and push them to Docker Hub, as shown in Steps 7 and 8.

Step 1 — Installing Docker

The Docker installation package available in the official Ubuntu repository may not be the latest version. To ensure we get the latest version, we’ll install Docker from the official Docker repository. To do that, we’ll add a new package source, add the GPG key from Docker to ensure the downloads are valid, and then install the package.

First, update your existing list of packages:

sudo apt update

Next, install a few prerequisite packages which let apt use packages over HTTPS:

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

Then add the GPG key for the official Docker repository to your system:

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"

This will also update our package database with the Docker packages from the newly added repo.

Make sure you are about to install from the Docker repo instead of the default Ubuntu repo:

apt-cache policy docker-ce

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

docker-ce:
  Installed: (none)
  Candidate: 5:19.03.9~3-0~ubuntu-focal
  Version table:
     5:19.03.9~3-0~ubuntu-focal 500
        500 https://download.docker.com/linux/ubuntu focal/stable amd64 Packages

Notice that docker-ce is not installed, but the candidate for installation is from the Docker repository for Ubuntu (focal).

Finally, install Docker:

sudo apt install docker-ce

Docker should now be installed, the daemon started, and the process enabled to start on boot. Check that it’s running:

sudo systemctl status docker

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

Output
● docker.service - Docker Application Container Engine
     Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)
     Active: active (running) since Tue 2020-05-19 17:00:41 UTC; 17s ago
TriggeredBy: ● docker.socket
       Docs: https://docs.docker.com
   Main PID: 24321 (dockerd)
      Tasks: 8
     Memory: 46.4M
     CGroup: /system.slice/docker.service
             └─24321 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock

Installing Docker now gives you not just the Docker service (daemon) but also the docker command line utility, or the Docker client. We’ll explore how to use the docker command later in this tutorial.

Step 2 — Executing the Docker Command Without Sudo (Optional)

By default, 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 installation process. If you attempt to run the docker command without prefixing it with sudo or without being in the docker group, you’ll get an output like this:

Output
docker: Cannot connect to the Docker daemon. Is the docker daemon running on this host?.
See 'docker run --help'.

If you want to avoid typing sudo whenever you run the docker command, add your username to the docker group:

sudo usermod -aG docker ${USER}

To apply the new group membership, log out of the server and back in, or type the following:

su - ${USER}

You will be prompted to enter your user’s password to continue.

Confirm that your user is now added to the docker group by typing:

groups

Output
sammy sudo docker

If you need to add a user to the docker group that you’re not logged in as, declare that username explicitly using:

sudo usermod -aG docker username

The rest of this article assumes you are running the docker command as a user in the docker group. If you choose not to, please prepend the commands with sudo.

Let’s explore the docker command next.

Step 3 — Using the Docker Command

Using docker consists of passing it a chain of options and commands followed by arguments. The syntax takes this form:

docker [option] [command] [arguments]

To view all available subcommands, type:

docker

As of Docker 19, the complete list of available subcommands includes:

Output
  attach      Attach local standard input, output, and error streams to a running container
  build       Build an image from a Dockerfile
  commit      Create a new image from a container's changes
  cp          Copy files/folders between a container and the local filesystem
  create      Create a new container
  diff        Inspect changes to files or directories on a container's filesystem
  events      Get real time events from the server
  exec        Run a command in a running container
  export      Export a container's filesystem as a tar archive
  history     Show the history of an image
  images      List images
  import      Import the contents from a tarball to create a filesystem image
  info        Display system-wide information
  inspect     Return low-level information on Docker objects
  kill        Kill one or more running containers
  load        Load an image from a tar archive or STDIN
  login       Log in to a Docker registry
  logout      Log out from a Docker registry
  logs        Fetch the logs of a container
  pause       Pause all processes within one or more containers
  port        List port mappings or a specific mapping for the container
  ps          List containers
  pull        Pull an image or a repository from a registry
  push        Push an image or a repository to a registry
  rename      Rename a container
  restart     Restart one or more containers
  rm          Remove one or more containers
  rmi         Remove one or more images
  run         Run a command in a new container
  save        Save one or more images to a tar archive (streamed to STDOUT by default)
  search      Search the Docker Hub for images
  start       Start one or more stopped containers
  stats       Display a live stream of container(s) resource usage statistics
  stop        Stop one or more running containers
  tag         Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE
  top         Display the running processes of a container
  unpause     Unpause all processes within one or more containers
  update      Update configuration of one or more containers
  version     Show the Docker version information
  wait        Block until one or more containers stop, then print their exit codes

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

docker docker-subcommand --help

To view system-wide information about Docker, use:

docker info

Let’s explore some of these commands. We’ll start by working with images.

Step 4 — Working with Docker Images

Docker containers are built from Docker images. By default, Docker pulls these images from Docker Hub, a Docker registry managed by Docker, the company behind the Docker project. Anyone can host their Docker images on Docker Hub, so most applications and Linux distributions you’ll need will have images hosted there.

To check whether you can access and download images from Docker Hub, type:

docker run hello-world

The output will indicate that Docker in working correctly:

Output
Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
0e03bdcc26d7: Pull complete
Digest: sha256:6a65f928fb91fcfbc963f7aa6d57c8eeb426ad9a20c7ee045538ef34847f44f1
Status: Downloaded newer image for hello-world:latest

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

Docker was initially unable to find the hello-world image locally, so it downloaded the image from Docker Hub, which is the default repository. Once the image downloaded, Docker created a container from the image and the application within the container executed, displaying the message.

You can search for images available on Docker Hub by using the docker command with the search subcommand. For example, to search for the Ubuntu image, type:

docker search ubuntu

The script will crawl Docker Hub and return a listing of all images whose name match the search string. In this case, the output will be similar to this:

Output
NAME                                                      DESCRIPTION                                     STARS               OFFICIAL            AUTOMATED
ubuntu                                                    Ubuntu is a Debian-based Linux operating sys…   10908               [OK]
dorowu/ubuntu-desktop-lxde-vnc                            Docker image to provide HTML5 VNC interface …   428                                     [OK]
rastasheep/ubuntu-sshd                                    Dockerized SSH service, built on top of offi…   244                                     [OK]
consol/ubuntu-xfce-vnc                                    Ubuntu container with "headless" VNC session…   218                                     [OK]
ubuntu-upstart                                            Upstart is an event-based replacement for th…   108                 [OK]
ansible/ubuntu14.04-ansible                               Ubuntu 14.04 LTS with
...

In the OFFICIAL column, OK indicates an image built and supported by the company behind the project. Once you’ve identified the image that you would like to use, you can download it to your computer using the pull subcommand.

Execute the following command to download the official ubuntu image to your computer:

docker pull ubuntu

You’ll see the following output:

Output
Using default tag: latest
latest: Pulling from library/ubuntu
d51af753c3d3: Pull complete
fc878cd0a91c: Pull complete
6154df8ff988: Pull complete
fee5db0ff82f: Pull complete
Digest: sha256:747d2dbbaaee995098c9792d99bd333c6783ce56150d1b11e333bbceed5c54d7
Status: Downloaded newer image for ubuntu:latest
docker.io/library/ubuntu:latest

After an image has been downloaded, you can then run a container using the downloaded image with the run subcommand. As you saw with the hello-world example, if an image has not been downloaded when docker is executed with the run subcommand, the Docker client will first download the image, then run a container using it.

To see the images that have been downloaded to your computer, type:

docker images

The output will look similar to the following:

Output
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
ubuntu              latest              1d622ef86b13        3 weeks ago         73.9MB
hello-world         latest              bf756fb1ae65        4 months ago        13.3kB

As you’ll see later in this tutorial, images that you use to run containers can be modified and used to generate new images, which may then be uploaded (pushed is the technical term) to Docker Hub or other Docker registries.

Let’s look at how to run containers in more detail.

Step 5 — Running a Docker Container

The hello-world container you ran in the previous step is an example of a container that runs and exits after emitting a test message. Containers can be much more useful than that, and they can be interactive. After all, they are similar to virtual machines, only more resource-friendly.

As an example, let’s run a container using the latest image of Ubuntu. The combination of the -i and -t switches gives you interactive shell access into the container:

docker run -it ubuntu

Your command prompt should change to reflect the fact that you’re now working inside the container and should take this form:

Output
root@d9b100f2f636:/#

Note the container id in the command prompt. In this example, it is d9b100f2f636. You’ll need that container ID later to identify the container when you want to remove it.

Now you can run any command inside the container. For example, let’s update the package database inside the container. You don’t need to prefix any command with sudo, because you’re operating inside the container as the root user:

apt update

Then install any application in it. Let’s install Node.js:

apt install nodejs

This installs Node.js in the container from the official Ubuntu repository. When the installation finishes, verify that Node.js is installed:

node -v

You’ll see the version number displayed in your terminal:

Output
v10.19.0

Any changes you make inside the container only apply to that container.

To exit the container, type exit at the prompt.

Let’s look at managing the containers on our system next.

Step 6 — Managing Docker Containers

After using Docker for a while, you’ll have many active (running) and inactive containers on your computer. To view the active ones, use:

docker ps

You will see output similar to the following:

Output
CONTAINER ID        IMAGE               COMMAND             CREATED

In this tutorial, you started two containers; one from the hello-world image and another from the ubuntu image. Both containers are no longer running, but they still exist on your system.

To view all containers — active and inactive, run docker ps with the -a switch:

docker ps -a

You’ll see output similar to this:

1c08a7a0d0e4        ubuntu              "/bin/bash"         2 minutes ago       Exited (0) 8 seconds ago                       quizzical_mcnulty
a707221a5f6c        hello-world         "/hello"            6 minutes ago       Exited (0) 6 minutes ago                       youthful_curie

To view the latest container you created, pass it the -l switch:

docker ps -l

CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                      PORTS               NAMES
1c08a7a0d0e4        ubuntu              "/bin/bash"         2 minutes ago       Exited (0) 40 seconds ago                       quizzical_mcnulty

To start a stopped container, use docker start, followed by the container ID or the container’s name. Let’s start the Ubuntu-based container with the ID of 1c08a7a0d0e4:

docker start 1c08a7a0d0e4

The container will start, and you can use docker ps to see its status:

Output
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
1c08a7a0d0e4        ubuntu              "/bin/bash"         3 minutes ago       Up 5 seconds                            quizzical_mcnulty

To stop a running container, use docker stop, followed by the container ID or name. This time, we’ll use the name that Docker assigned the container, which is quizzical_mcnulty:

docker stop quizzical_mcnulty

Once you’ve decided you no longer need a container anymore, remove it with the docker rm command, again using either the container ID or the name. Use the docker ps -a command to find the container ID or name for the container associated with the hello-world image and remove it.

docker rm youthful_curie

You can start a new container and give it a name using the --name switch. You can also use the --rm switch to create a container that removes itself when it’s stopped. See the docker run help command for more information on these options and others.

Containers can be turned into images which you can use to build new containers. Let’s look at how that works.

Step 7 — Committing Changes in a Container to a Docker Image

When you start up a Docker image, you can create, modify, and delete files just like you can with a virtual machine. The changes that you make will only apply to that container. You can start and stop it, but once you destroy it with the docker rm command, the changes will be lost for good.

This section shows you how to save the state of a container as a new Docker image.

After installing Node.js inside the Ubuntu container, you now have a container running off an image, but the container is different from the image you used to create it. But you might want to reuse this Node.js container as the basis for new images later.

Then commit the changes to a new Docker image instance using the following command.

docker commit -m "What you did to the image" -a "Author Name" container_id repository/new_image_name

The -m switch is for the commit message that helps you and others know what changes you made, while -a is used to specify the author. The container_id is the one you noted earlier in the tutorial when you started the interactive Docker session. Unless you created additional repositories on Docker Hub, the repository is usually your Docker Hub username.

For example, for the user sammy, with the container ID of d9b100f2f636, the command would be:

docker commit -m "added Node.js" -a "sammy" d9b100f2f636 sammy/ubuntu-nodejs

When you commit an image, the new image is saved locally on your computer. Later in this tutorial, you’ll learn how to push an image to a Docker registry like Docker Hub so others can access it.

Listing the Docker images again will show the new image, as well as the old one that it was derived from:

docker images

You’ll see output like this:

Output
REPOSITORY               TAG                 IMAGE ID            CREATED             SIZE
sammy/ubuntu-nodejs   latest              7c1f35226ca6        7 seconds ago       179MB
...

In this example, ubuntu-nodejs is the new image, which was derived from the existing ubuntu image from Docker Hub. The size difference reflects the changes that were made. And in this example, the change was that NodeJS was installed. So next time you need to run a container using Ubuntu with NodeJS pre-installed, you can just use the new image.

You can also build Images from a Dockerfile, which lets you automate the installation of software in a new image. However, that’s outside the scope of this tutorial.

Now let’s share the new image with others so they can create containers from it.

Step 8 — Pushing Docker Images to a Docker Repository

The next logical step after creating a new image from an existing image is to share it with a select few of your friends, the whole world on Docker Hub, or other Docker registry that you have access to. To push an image to Docker Hub or any other Docker registry, you must have an account there.

This section shows you how to push a Docker image to Docker Hub. To learn how to create your own private Docker registry, check out How To Set Up a Private Docker Registry on Ubuntu or How To Set Up a Private Docker Registry on Ubuntu.

To push your image, first log into Docker Hub.

docker login -u docker-registry-username

You’ll be prompted to authenticate using your Docker Hub password. If you specified the correct password, authentication should succeed.

docker tag sammy/ubuntu-nodejs docker-registry-username/ubuntu-nodejs

Then you may push your own image using:

docker push docker-registry-username/docker-image-name

To push the ubuntu-nodejs image to the sammy repository, the command would be:

docker push sammy/ubuntu-nodejs

The process may take some time to complete as it uploads the images, but when completed, the output will look like this:

Output
The push refers to a repository [docker.io/sammy/ubuntu-nodejs]
e3fbbfb44187: Pushed
5f70bf18a086: Pushed
a3b5c80a4eba: Pushed
7f18b442972b: Pushed
3ce512daaf78: Pushed
7aae4540b42d: Pushed
...

After pushing an image to a registry, it should be listed on your account’s dashboard, like that show in the image below.

If a push attempt results in an error of this sort, then you likely did not log in:

Output
The push refers to a repository [docker.io/sammy/ubuntu-nodejs]
e3fbbfb44187: Preparing
5f70bf18a086: Preparing
a3b5c80a4eba: Preparing
7f18b442972b: Preparing
3ce512daaf78: Preparing
7aae4540b42d: Waiting
unauthorized: authentication required

Log in with docker login and repeat the push attempt. Then verify that it exists on your Docker Hub repository page.

You can now use docker pull sammy/ubuntu-nodejs to pull the image to a new machine and use it to run a new container.

Docker vs Docker Compose

While Docker lets you build and run containers, managing multi-container applications with just Docker can be tedious. That’s where Docker Compose comes in.

Docker Compose is a tool for defining and running multi-container Docker applications using a YAML file. Instead of manually running separate containers for a web server, database, and caching layer, you can define them all in a docker-compose.yml file and run them with:

docker-compose up

For a detailed guide on using Docker Compose, including how to set up complex multi-container applications and manage their configurations, check out our tutorial on How To Install and Use Docker Compose on Ubuntu. This guide will walk you through creating and managing multi-container applications with Docker Compose, from basic setups to more complex configurations.

For more, see How To Install and Use Docker Compose on Ubuntu.

Troubleshooting Common Docker Installation Issues

Problem: docker: command not found

Fix: The Docker CLI isn’t in your $PATH. Reinstall Docker or ensure /usr/bin is included.

sudo apt install docker-ce docker-ce-cli containerd.io

Problem: Cannot connect to the Docker daemon

Fix: Docker isn’t running, or your user isn’t in the docker group.

sudo systemctl start docker
sudo usermod -aG docker $USER

Then log out and log back in.

Problem: GPG key or repository error

Fix: If the keyserver or Docker GPG key changes, refer to Docker’s official docs for the latest key and repository steps. If you’re using Ubuntu 22.04, you may want to check our guide on How To Install and Use Docker on Ubuntu 22.04 for version-specific instructions. For automated installation that can help avoid these issues, consider using our guide on How To Use Ansible to Install and Set Up Docker on Ubuntu.

Docker Desktop on Ubuntu (Beta)

Docker Desktop is now available in beta for Linux distributions like Ubuntu. It provides a GUI, bundled Docker Engine, and Kubernetes support.

To install Docker Desktop on Ubuntu:

sudo apt install ./docker-desktop-<version>-<arch>.deb

Refer to Docker Desktop for Linux docs for prerequisites and download links.

Note: Docker Desktop is suited for development environments. For server-side installs, use Docker CE.

Installing Docker Using a Dockerfile

For automated environments, install Docker using a Dockerfile. Here’s an example:

FROM ubuntu:20.04

RUN apt-get update && \
    apt-get install -y apt-transport-https ca-certificates curl gnupg lsb-release && \
    curl -fsSL https://download.docker.com/linux/ubuntu/gpg | apt-key add - && \
    add-apt-repository \
   "deb [arch=amd64] https://download.docker.com/linux/ubuntu focal stable" && \
    apt-get update && \
    apt-get install -y docker-ce docker-ce-cli containerd.io

For more advanced automation options, you can also use Ansible to install and configure Docker. Check out our guide on How To Use Ansible to Install and Set Up Docker on Ubuntu. This is particularly useful if you need to manage Docker installations across multiple servers or want to maintain consistent configurations in your infrastructure.

How to Uninstall Docker on Ubuntu

To remove Docker from your system, run:

sudo apt purge docker-ce docker-ce-cli containerd.io
sudo rm -rf /var/lib/docker
sudo rm -rf /var/lib/containerd

Frequently Asked Questions

1. What is the best way to install Docker on Ubuntu?

The recommended and most reliable way to install Docker on Ubuntu is by using Docker’s official repository. This approach ensures you always receive the latest stable version, complete with security patches and updates directly from Docker. To do this, you first update your package index and install prerequisites like apt-transport-https, ca-certificates, curl, gnupg, and lsb-release. Next, you add Docker’s official GPG key and set up the stable repository. After updating your package index again, you can install Docker Engine and related components using

sudo apt install docker-ce docker-ce-cli containerd.io

This method is preferred over using the default Ubuntu repositories, which may contain outdated versions. By following Docker’s official installation steps, you ensure compatibility with the latest features, bug fixes, and security enhancements, making your Docker experience on Ubuntu both robust and secure.

2. Do I need sudo to run Docker commands?

By default, Docker requires root privileges to run its commands, which means you need to prepend sudo to every Docker command. However, you can avoid this by adding your user to the docker group, which grants permission to run Docker commands without sudo. To do this, execute

sudo usermod -aG docker $USER

and then log out and log back in for the changes to take effect. This step modifies your user’s group memberships, allowing Docker to be run as a non-root user. Keep in mind that adding users to the docker group grants them root-level access to the Docker daemon, so only add trusted users. If you skip this step, you’ll encounter permission errors when running Docker commands without sudo. For security and convenience, it’s best to add your user to the docker group if you use Docker frequently.

3. How do I verify if Docker is running correctly?

To confirm that Docker is installed and running properly on your Ubuntu system, you can use a couple of simple commands. First, run

docker info

to display detailed information about the Docker installation, including server version, storage driver, and running containers. If Docker is running, this command will return a wealth of information; if not, you’ll see an error. Another common test is to run

docker run hello-world

This command downloads a test image from Docker Hub and runs it in a container. If everything is set up correctly, you’ll see a message indicating that Docker is working as expected. If you encounter errors, check that the Docker service is running with

sudo systemctl status docker

and review any error messages for troubleshooting. These steps help ensure your Docker installation is functional and ready for use.

4. Can I install a specific version of Docker?

Yes, you can install a specific version of Docker on Ubuntu, which is useful if you need compatibility with certain applications or want to avoid the latest changes. First, list all available Docker versions in the repository using

apt-cache madison docker-ce

This command will display a list of version strings. Once you identify the desired version, install it by running

sudo apt install docker-ce=<VERSION_STRING>

replacing <VERSION_STRING> with the exact version number (for example, 5:20.10.7~3-0~ubuntu-focal). This approach ensures you have precise control over the Docker version on your system. Remember to also specify matching versions for

docker-ce-cli

and

containerd.io

if needed. Pinning a specific version can help maintain stability in production environments or when working with legacy projects that require a particular Docker release.

5. What’s the difference between Docker and Docker Compose?

Docker and Docker Compose are related but serve different purposes. Docker is a platform that allows you to build, ship, and run individual containers, each encapsulating an application and its dependencies. It’s ideal for running single services or applications in isolation. Docker Compose, on the other hand, is a tool designed to define and manage multi-container applications. With Compose, you use a YAML file (docker-compose.yml) to specify how multiple containers should interact, their configurations, networks, and volumes. This makes it easy to orchestrate complex applications consisting of several interconnected services, such as a web server, database, and cache. While Docker alone is sufficient for simple use cases, Docker Compose streamlines the process of managing multi-container setups, making development, testing, and deployment of complex applications much more efficient and reproducible.

6. How do I remove Docker from my system?

To completely uninstall Docker from your Ubuntu system, you need to remove the Docker packages and delete any associated data. Start by running

sudo apt purge docker-ce docker-ce-cli containerd.io

to remove the Docker Engine, CLI, and container runtime. This command deletes the installed packages but leaves configuration files and data directories intact. To fully clean up, remove Docker’s data directories with

sudo rm -rf /var/lib/docker

and

sudo rm -rf /var/lib/containerd

These directories store images, containers, volumes, and other persistent data. If you added your user to the docker group, you may also want to remove the group with

sudo groupdel docker

After these steps, Docker and all its data will be removed from your system. Always back up important data before uninstalling to avoid accidental loss.

7. Is Docker Desktop available for Ubuntu, and should I use it?

Yes, Docker Desktop is now available in beta for Linux distributions, including Ubuntu. Docker Desktop provides a graphical user interface (GUI) for managing containers, images, volumes, and networks, making it easier for users who prefer not to work exclusively with the command line. It also bundles the Docker Engine and offers integrated Kubernetes support, which is useful for development and testing environments. To install Docker Desktop on Ubuntu, download the appropriate .deb package from Docker’s official website and install it using

sudo apt install ./docker-desktop-<version>-<arch>.deb

However, Docker Desktop is primarily intended for development and not recommended for production servers. For server-side or headless environments, it’s better to use Docker Engine Community Edition (CE) via the command line. Always check Docker’s documentation for prerequisites and the latest installation instructions before proceeding.

Conclusion

In this comprehensive tutorial, you’ve successfully installed Docker on Ubuntu, mastered the fundamentals of container management, and learned how to work with Docker images and containers. You’ve also gained hands-on experience with Docker Hub by pushing a modified image to the registry. These skills form a solid foundation for container-based development and deployment. To further enhance your Docker expertise, we encourage you to explore the other Docker tutorials in the DigitalOcean Community, where you’ll find advanced topics like container orchestration, networking, and security best practices.