How to Succeed (Or Fail) with Docker

Docker was developed in 2012 as a tool for virtualization applications in a reproducible environment called containers. Containers allow development teams to package their application, third-party libraries, and other dependencies and ship it out as a single package. These packages consistently run on any Docker-enabled environment. Gone are the days of “It worked on my environment!” 

Now, some may say, “Why don’t we just build a virtual machine?” This can be a valid option in the right situation, but it is time consuming and resource intensive. Instead of creating a whole virtualized operating system, Docker allows the application container to use the same Linux kernel as the host machine boosting performance.

When to Use Docker

Docker is an amazing tool, but like any other, you must know and understand when to use it. 

1. Software Development
   Docker allows for teams large and small to develop and test applications in the same environment, no matter the individual developer’s programming environment.
2. Testing Technologies
   With the use of Docker Compose and Docker Hub, it’s incredibly easy for teams to test new technologies and applications. Ever curious if switching to a self-hosted GitLab or bug tracking with Mantis was the right thing for your company? Docker allows you to test these applications out in a matter of minutes with minimal overhead. And when you are done testing, you can simply delete the container and move on.
3. Application Isolation
   Have you ever needed to run multiple applications of the same server that may have conflicting dependencies? Docker allows you to sidestep these issues by completely isolating applications into containers, removing any conflicts.
4. Highly Available Micro Services
   This is where Docker truly shines: small, stateless applications that may need to be deployed rapidly or spun down when the resources are no longer needed. 

When Not to Use Docker

Docker is great for many situations, but there are some cases where it falls short.

1. Production Environment
   Docker can be used for production environments, but it should be noted that there are many more steps to making a production-ready Docker container that would be considered stable.
2. Performance
   Since Docker shares the host environment’s resources, it does impose a cost to performance. If you want to squeeze the most out of your applications, you may want to skip Docker and host your applications as close to the native OS as you can. 
3. Databases
   Docker is best used for stateless applications and should not be used to host databases. Docker containers have been known to have stability issues with database writes and can be killed mid-process. Databases are best left hosted on a host machine directly.

Overall, Docker has become an essential tool for many organizations, allowing teams to test in reproducible environments and deploy applications across many different environments with the knowledge that it will run as originally intended. 

Here at Buildable, we have embraced Docker for software, IT, and DevOps and have received a boom in our productivity.