Best Practices When Using Docker

Best practices for Docker usage include using official images, controlling container resource usage, optimizing layers, and running containers as non-root users. These practices enhance security, efficiency, and maintainability. By following these guidelines, we build secure and efficient containerized applications while minimizing potential risks and resource consumption. We’ll discuss them further below.

Use official images

Start with official Docker images from trusted sources to minimize security risks and ensure reliability. Official images come from trusted sources, which reduces the risk of security vulnerabilities or malicious code. This practice helps ensure the security and reliability of containerized applications.

Create minimal images

Building minimal container images involves including only the components, files, and dependencies that are necessary for the application to function. Exclude unnecessary files and libraries. Smaller images are faster to download, deploy, and start, leading to better performance and resource efficiency.

Optimize layers

Docker uses a layered file system for images, and each Dockerfile instruction creates a new layer. Optimizing layers involves organizing these instructions to minimize the number of layers in the image. Fewer layers make image builds faster and more efficient because Docker can reuse cached layers, reducing the need to rebuild unchanged parts of the image.

Run containers as non-root users

Running containers as non-root users is a crucial security practice. By default, containers typically run as the root user within the container, which can introduce security vulnerabilities. When containers run as non-root users, they have limited access to system resources, reducing the impact of security breaches or vulnerabilities. Doing this follows the principle of least privilege.

Limit container capabilities

Capabilities restrict specific actions that a process can perform, such as network configuration or mounting file systems. By limiting these capabilities, you reduce the potential attack surface. Docker allows you to fine-tune container security by employing limiting capabilities.

Use Docker Compose

Docker Compose simplifies the orchestration of multiple containers that need to work together, such as microservices. It streamlines deployment, scaling, and networking. With Docker Compose, the application’s structure, dependencies, and configurations are in a declarative format, making it easier to manage complex containerized applications.

Security scanning

Regularly scanning Docker images for vulnerabilities is an essential security practice. Security scanning tools analyze images for known vulnerabilities in packages and dependencies. One of those tools is Trivy.