Docker is not the only container technology, but it is the de facto container standard and is unique to container applications and developers. Docker support is already integrated into a wide variety of products and platforms, and many organizations already use Docker containers or are trying to figure out how to keep up.
Docker isn’t too difficult to use, but it can be more efficient if you follow some best practices. Here are five Docker best practices you should keep in mind, whether you’re already using Docker or just thinking about using it in the future.
1. Pay attention to inheritance and dependencies
A container inherits its parent image, usually including its base operating system and dependencies, such as dependency packages, default users, and so on. Those inherited properties and dependencies can expose your container to unnecessary risks. Make sure you know the inherited properties and take any other steps necessary to further isolate and secure your containers.
2. Limit container interactions
Container security has become a serious concern for many organizations, especially the security of interactions between containers and interactions with the outside world. Containers should not accept access from exposed ports on any network card. You should take steps to control the internal interaction of containers and limit the number of containers connected to the outside to minimize external risks.
3. Monitor container vulnerabilities
One of the challenges with a repository like Docker Hub is that once the container image is uploaded to the repository, no one is responsible for its security. It may be fine when initially created, but over time, new vulnerabilities and defects are discovered that you need to scan for before using the container in production. Tools like Twistlock can help you monitor and identify vulnerabilities in container images.
4. Run the container as read-only as possible
One of the best and easiest ways to limit the exposure risk of containers is to run them in read-only mode. This is obviously not true of all containers; in order for an application to work properly, some containers must accept some sort of sequential access requests, and these containers can run in read-only mode. Another rule is never to run containers in privileged mode.
5. Keep it simple
Make your Docker container system as simple as possible. You should run the process in a separate container.
If you have services that depend on each other, you should use container linking to connect the two containers rather than combining them in the same Docker container. You should also focus on keeping the resources the container loads small, not loading unnecessary packages or services, and ensuring that your container design is easy to replace, as unnecessary resources will only make the file bigger and waste resources. Systems made up of containers are often very unstable, and containers should be easily created and removed on demand.
The list above doesn’t cover all the guidelines, and to be honest, I could write 25 or even 50 Docker best practices. This is just a great start to help you maximize the value of Docker containers while helping you take some steps to ensure that your containerized applications and data are safe.