05 Jan 2016

For the last couple of months, I’ve been more and more intrigued by Docker. When I first started looking into it, I understood it conceptually… but I didn’t know how it could benefit me or my world in anyway. So, I followed my intrigue as usual and dug in further.

DISCLAIMER I am not and nor do I claim to be an expert on Linux, Docker, Containers or Microservice Architecture, these are just my thoughts and understanding.

Without digging into my background too much, I just wanted to paint a picture of where I coming from and what I am hoping to get from Docker. I currently lead a team of full-stack Developers who build and maintain a handful of Internally built Enterprise Applications, predominately on .Net and Java. Over the past couple of years, we have had an initial stab at microservice architecture, breaking down some of our monolith applications into independent services and decoupling our UI from logic using RESTful services. This was a breakthrough (to some degree) and there has been a lot of challenges, but I’ll save all the detail for another blog post someday.

By breaking down our application into smaller services, we introduced a new set of challenges, one of them being we’ve now distributed our complexity. We have also increased the number of build and deployment configurations we now own. Unfortunately, we do not have access to a DevOps team and the company’s infrastructure team just focus on infrastructure (i.e. they will provision us a VM or tin with the OS we request), so we have traditionally looked after everything you see in the diagram below; from my reading, this seems to be quite common in small teams.

We have to take care of frameworks and software, IIS configuration, Builds and Deployments. To our credit, we have automated all of our CI / CD pipeline (thanks TeamCity and Octopus) but we still need to know a lot about IIS, Server Administration and all of that other noise. I call it noise because it takes us away from what we are really paid to do… focus on adding value to the business through application development, so I am constantly looking at ways to make my developers lives easier.

For a while now, I’ve been saying to my management and infrastructure teams that “As Developers, we do not give a ** about infrastructure!”, so the idea of something like PaaS (Platform as a Service) sounds like music to my ears, and for a while we were looking at Azure or Amazon as our way forward. But understandably, due to sensitive data we work on, moving to the cloud is challenging and not always possible.

Just to make something clear, we were not looking at PaaS platforms like Azure because our infrastructure performance is letting us down (our internal applications probably generates as much traffic a month as Netflix generates in a few seconds), we are looking at this for the following reasons:

• Increase time to market
• Reduce operations in the team
• Focus on Business Value
• Get rid of our environments and just have production only (The reason i’m mostly excited about - more on this in another blog)

So let’s bring this all back to the original question, what is Docker? well, put simply Docker is a container based platform technology. It’s not quite a PaaS, but it’s almost like a half way house. In-fact, this white paper from Docker refers to it as CaaS (Container-as-a-Service). Building applications on the CaaS model means we don’t need to know too much about the infrastructure (as we have our Infrastructure team taking care of that) but we still get a good control of the configuration of the application, things like the framework version, any specific environment settings, ports, etc… This CaaS model feels right at the moment for our team. It still gives us some degree of flexibility, configuration control and less needing to worry about OS level operations.

Here are some of the other benefits I can see for my team moving to Docker: - Process isolation - Application sand-boxing - Reduce server overhead - Application portability - Developer Productivity - No more “works on my machine” but doesn’t work on production situations

Here is a small list of resources I’ve been reading and viewing: - Docker Documentation - Docker White Paper - DockerCon Videos - Pluralsight Course from Nigel Poulton