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Granting Docker Permissions to Non-Root User in Ubuntu 18.04

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In this tutorial, we will guide you through the process of granting Docker permissions to a non-root user in Ubuntu 18.04. This is an essential step in managing Docker containers securely and efficiently.

Quick Answer

To grant Docker permissions to a non-root user in Ubuntu 18.04, you can create a Docker group, add the non-root user to the group, and activate the changes. This allows the non-root user to run Docker commands without needing root access.

Introduction

By default, Docker requires root privileges to execute commands. This can be a security risk as it allows the user to have full control over the system. To mitigate this risk, we can create a Docker group and add non-root users to it. This allows them to execute Docker commands without needing root access.

Prerequisites

To follow this guide, you will need:

  • A system running Ubuntu 18.04
  • Docker installed on your system
  • Access to a terminal window/command line
  • A non-root user with sudo privileges

Step 1: Creating the Docker Group

The first step is to create a Unix group named “docker”. This can be done using the groupadd command:

sudo groupadd docker

In this command, sudo is used to run the command with root privileges, groupadd is the command to add a new group, and docker is the name of the group.

Step 2: Adding the Non-Root User to the Docker Group

Next, we need to add the non-root user to the “docker” group. Replace “$USER” with the username of the non-root user:

sudo gpasswd -a $USER docker

In this command, gpasswd -a is used to add a user to a group. $USER is a placeholder for the non-root user’s username, and docker is the name of the group.

Step 3: Activating the Changes

For the changes to take effect, you can either log out and log back in, or use the following command:

newgrp docker

The newgrp command is used to log into a new group. The group name docker is passed as an argument to the command.

Step 4: Verifying the Changes

To ensure that the non-root user can now run Docker commands without using sudo, run the following command:

docker run hello-world

This command runs the hello-world Docker image. If everything is set up correctly, you should see a message from Docker saying that your installation appears to be working correctly.

Security Considerations

While this setup allows the non-root user to run Docker commands, it’s important to note that the Docker daemon itself still runs as the root user. This means that the non-root user has access to Docker through the Unix socket, which can pose a security risk if not managed properly. Therefore, it’s crucial to follow security best practices and keep the Docker daemon and its associated files secure.

For more information and detailed instructions, you can refer to the official Docker documentation on managing Docker as a non-root user: post-installation steps for Linux.

Conclusion

In this tutorial, we have shown you how to grant Docker permissions to a non-root user in Ubuntu 18.04. This is an important step in managing Docker containers securely and efficiently. However, remember to always follow best security practices to keep your system secure.

Why do I need to grant Docker permissions to a non-root user?

Granting Docker permissions to a non-root user is important for security reasons. By default, Docker requires root privileges to execute commands, which can be a security risk as it gives full control over the system. By creating a Docker group and adding non-root users to it, they can execute Docker commands without needing root access, thereby mitigating the security risk.

How do I create a Docker group in Ubuntu 18.04?

To create a Docker group in Ubuntu 18.04, you can use the groupadd command with sudo privileges. For example, sudo groupadd docker will create a group named "docker".

How do I add a non-root user to the Docker group?

To add a non-root user to the Docker group, you can use the gpasswd -a command with sudo privileges. Replace "$USER" with the username of the non-root user. For example, sudo gpasswd -a $USER docker will add the non-root user to the "docker" group.

How can I activate the changes after adding a non-root user to the Docker group?

To activate the changes after adding a non-root user to the Docker group, you can either log out and log back in, or use the newgrp command. For example, newgrp docker will log the user into the "docker" group.

How can I verify if the non-root user can run Docker commands without using sudo?

To verify if the non-root user can run Docker commands without using sudo, you can run the command docker run hello-world. If everything is set up correctly, you should see a message from Docker stating that your installation appears to be working correctly.

What security considerations should I keep in mind when granting Docker permissions to a non-root user?

It’s important to note that even though the non-root user can run Docker commands, the Docker daemon itself still runs as the root user. This means that the non-root user has access to Docker through the Unix socket, which can pose a security risk if not managed properly. It is crucial to follow security best practices and keep the Docker daemon and its associated files secure. For more information, refer to the official Docker documentation on managing Docker as a non-root user.

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