Why are Windows containers an important topic?

Have you ever asked yourself, “Why should I care about Windows containers?” Many DevOps engineers and solution architects excel in Linux containerization, helping their companies with re-platforming legacy Linux applications into containers to architect, deploy, and manage complex microservices environments. However, many organizations still run tons of Windows applications, such as ASP.NET websites or .NET Framework applications, which are usually left behind during the modernization journey.

Through many customer engagements I have had in the past, there were two main aspects that meant Windows containers weren’t an option for DevOps engineers and solution architects.

The first was a lack of Windows operational system expertise in the DevOps team. Different system administrators and teams usually manage Windows and Linux, each using the tools that best fit their needs. For instance, a Windows system administrator will prefer System Center Configuration Manager (SCCM) as a Configuration Management solution. In contrast, a Linux system administrator would prefer Ansible.

Another example: a Windows system administrator would prefer System Center Operations Manager (SCOM) for deep insights, monitoring, and logging, whereas a Linux system administrator would prefer Nagios and an ELK stack. With the rapid growth of the Linux ecosystem toward containers, it is a natural and more straightforward career shift that a Linux system administrator needs to take in order to get up to speed as a DevOps engineer, whereas Windows system administrators aren’t exposed to all these tools and evolutions, making it a hard and drastic career shift, where you have to first learn about the Linux operating system (OS) and then the entire ecosystem around it.

The second aspect is the delusion that every .NET Framework application should be refactored to .NET (formerly .NET Core). In almost all engagements where the .NET Framework is a topic, I’ve heard developers talking about the beauty of refactoring their .NET Framework application into .NET and leveraging all the benefits available on a Linux ecosystem, such as ARM processors and the rich Linux tools ecosystem. While they are all 100% technically correct, as solution architects, we need to see the big picture, meaning the business investment behind it. We need to understand how much effort and investment of money will be required to fully refactor the application and its dependencies to move out of Windows, what will happen with the already purchased Windows Server licenses and management tools, and when the investment will break even. Sometimes, the annual IT budget will be better spent on new projects rather than refactoring 10-year-old applications, where the investment breakeven will take 5 or more years to come through, without much innovation on the application itself.

Now that we understand the most common challenges for Windows container adoption and the opportunity in front of us, we’ll dig into the Windows Server primitives for Windows containers, resource controls, and Windows base images.