Docker Compose host user best practice

When running Docker containers using Docker Compose on a Droplet (a virtual private server provided by DigitalOcean), it's essential to choose the right user to run the containers. The user you choose can have security implications, so let's break down the options:

Option 1: Running as the jake user
If you're the sole owner of the Droplet and don't plan to have multiple users or shared access, running as the jake user might be a decent choice. However, consider the following:

• Security: If another user gains access to your Droplet, they'll inherit the same permissions as jake.
• Container isolation: Running as a non-root user can provide some level of isolation between containers, as they'll run with the same privileges as the user running the container.

Option 2: Running as root user
Running as the root user can provide more privileges, but it also increases the attack surface. If you choose to run as root, keep in mind:

• Security: Running as root means that containers will run with the most privileged user, which can lead to increased exposure to potential security vulnerabilities.
• Container isolation: Since all containers run as root, there's no additional security benefit from running as a non-root user.

Option 3: Running as a separate user (e.g., dockeruser)
Creating a dedicated user for Docker, like dockeruser, can provide a middle ground. This approach:

• Security: If another user accesses your Droplet, they'll only inherit the same permissions as the dockeruser, which is a lower-privileged user.
• Container isolation: Running as a dedicated user like dockeruser can provide some level of isolation between containers, as they'll run with the same privileges as the user running the container.

Best practice:
To achieve a balance between security and functionality, consider creating a dedicated user for Docker and running your containers as that user. For example, you can create a user like dockeruser with a specific set of permissions, and then use Docker Compose to run your containers as that user.

Here's an example of how to create a dedicated user and run Docker Compose as that user:

sudo useradd dockeruser
sudo usermod -aG dockeruser docker
sudo chown -R dockeruser:dockeruser /path/to/docker/ data
docker-compose up

In this example:

1. useradd creates the dockeruser user.
2. usermod adds the dockeruser to the docker group.
3. chown changes the ownership of the Docker data directory to the dockeruser.
4. You can then run Docker Compose as the dockeruser using docker-compose up.

By following these best practices, you can maintain a safe and secure environment for your Docker containers while still leveraging the benefits of running them with a dedicated user.

When using Docker Compose on your Droplet, it's important to consider which user account to use for running your containers. Here are a few aspects to help you decide:

1. Security and Principle of Least Privilege:

Running as root:

• Pros: Convenient since it has all necessary permissions.
• Cons: Risky because any vulnerability in your application can lead to a full system compromise. Docker daemon itself often runs as root, so an exploit can affect the entire system.

Running as a non-root user (e.g., jake):

• Pros: Adheres to the principle of least privilege, minimizing the impact of any potential security issues.
• Cons: May require additional configuration to ensure the user has necessary access to resources and Docker.

2. Docker User and Permissions:

Regardless of whether you're using root or a non-root user to launch Docker containers, you need to ensure that your Docker service is securely configured:

• User namespace remapping: Helps ensure that even if a container is compromised, it won’t gain root privileges on the host.
• Non-root container users: Always prefer running the processes within your containers as non-root users. You can specify this in your Dockerfile as follows:

  FROM some-image
  USER some-non-root-user
  

3. Docker Group:

By default, Docker commands need root privileges, but you can create a Docker group and add your user (jake) to it:

• Create Docker group (if not already present):

  sudo groupadd docker
  

• Add your user to the Docker group:

  sudo usermod -aG docker jake
  

• After adding the user to the group, log out and log back in for the changes to take effect.

4. Configuring Docker Compose:

Open your docker-compose.yml and adjust configurations as needed. When invoking Docker Compose:

sudo -u jake docker-compose up

Or simply use:

docker-compose up

if the user jake is part of the Docker group.

Best Practice Summary:

1. Non-root User: Prefer using a non-root user to run Docker Compose. This enhances security by limiting privileges.
2. Configure Group Permissions: Add the user running Docker Compose (jake) to the Docker group.
3. Non-root Containers: Ensure containers run as non-root users to minimize the impact of any compromises within the container.
4. Security Configurations: Utilize Docker security mechanisms like user namespace remapping to further protect the host system.

Example workflow might look as follows:

1. Add jake to the Docker group.
2. Use Docker Compose as jake.
3. Ensure Docker containers run processes as non-root users.

Adhering to these practices can help in achieving a more secure Docker environment on your Droplet.