Docker has revolutionized software development with the use of containers. It is the leading container platform.

Containers remove many tedious processes out of software development. To maximize Docker’s potential, there are several best practices to implement to improve security, speed, and efficiency.

What Is Docker?

Docker is an open-source utility that eliminates repetitive tasks in software development.

It allows a developer to create a container, a controlled environment to run a process.

The container uses an image, a replica of a specific operating environment. This might sound like server virtualization, but Docker containers can be streamlined to execute a command with minimal resources. It can do this by loading only the libraries and dependencies that are required.

Docker Management Best Practices

Manage Docker Container Efficiency With Proper Planning

How can each process be mapped to a container?

Is a container the best tool to use? How will containers interact?

When mapping out your software process, it’s best to plan containers to use the least amount of work and resources needed.

Leverage Speed of Containers

A container doesn’t need a vast library of resources to run (unlike a virtual machine).

A container can load, execute, and unload from memory in a fraction of a second.  Separating tasks into smaller operations can dramatically improve performance.

Run a Single Process in Each Container

There’s no limit to the number of containers you can launch and delete, and each one can run a process in its own environment.

The more operations a container performs, the more resources it needs to load, slowing performance. Using one process per container helps limit those shared resources and reduce the overall container footprint. It can be easy to overcommit memory by running multiple tasks at once.

Dedicating a single process to each container – then closing – helps keep a clean and lean operating environment.

Use SWARM services

Consider using Docker Swarm services.

Docker swarm can automate many scheduling and resource management tasks. Swarm can also help scale quickly if rapid growth is a concern.

Avoid Using Containers For Storing Data

Data storage increases the input/output (disk read/writes) of a container.

A better tool for data storage is a shared software repository.

Access to the remote repository can be granted to containers on request. This reduces the size of the container. It also helps prevent different containers from loading and storing redundant data. Finally, it can avoid bottlenecks as multiple processes access storage.

Find and Keep a Docker Image That Works

An image holds all the configurations, dependencies, and code needed for a task.

It can be challenging to create an image for a whole application lifecycle. But once that image is created, avoid changing it. It might be tempting to update an image as dependencies are updated. But modifying an image mid-cycle can wreak havoc in the development process. This is especially true if different teams use images with incompatible dependencies.

Using a single image from start to finish makes troubleshooting easier.

All teams will be working with the same base environment. This means less time is needed to bring different sections of code together. Also, a single update can be done and tested across multiple containers.  This reduces the duplicated work of individual updates and code fixes. It also helps quality assurance teams find and fix problems more quickly.

Networking in containers

Containers in Docker are assigned IP addresses to communicate with each other.  This can create challenges in a network environment.

In the past, the ––LINK command was used to manage addressing and communications.  This feature is considered legacy and has been replaced with bridge networking.

User-defined bridge networking between containers allows access to all ports within the bridge network. It also blocks all ports to the outside world.  This creates a secure environment for containers.  Internal traffic flows uninterrupted and is protected from outside influence.

For more information on user-defined bridges (and other technology), see the Docker documentation.

Security Concerns With Containers

Many modern internet security protocols are retrofitted. This is because the original network developers did not build security into networking protocols.

Retrofitting security is always more difficult and expensive. A much better practice is to implement security during development.

Here are a few options to consider for managing the security of Docker containers.

  • Avoid running containers with root privileges.

Most Linux administrators are familiar with the hazards of granting full root privileges to users. Similar warnings apply to containers. A better practice is to create containers with only the privileges they need.

Use the –u tag to specify a user (instead of an administrator).

  • Secure Credentials

Keep credentials in a different place than where they’re used. Also, environmental variables are a better way to manage access within a container. Including credentials in the same container is like keeping a password on a sticky note. Worse case scenario, a breach in one container can quickly spread through a whole application.

Use the –PRIVILEGED tag sparingly.

By default, containers run in a more secure unprivileged mode.

Containers won’t be able to access other devices. If access to other devices is required, use the –privileged tag to grant access on a case-by-case basis.

  • Use third-party security applications

It’s always a good idea to have a second set of eyes review your security configuration. Third party tools leverage the skill of security specialists to analyze your software. They can also help scan your code for known vulnerabilities. Plus they often include a user-friendly interface for managing container security.

  • Consider switching to private software registries

Docker Hub maintains a free registry of software images, which can be quite helpful for newer or smaller developers.

However, security can be a concern when using these registries. It’s worth evaluating the costs and benefits of hosting your software registries.

Conclusion

In this article, we learned how to manage Docker containers.

Docker Containers are designed to streamline the software development process.

They also streamline the actual application with proper application and container management  Best of all; Docker promotes optimizing software functionality without compromising communication or security.