How to run Windows Containers? Not using Minikube !!!

How we ran Minikube?

In the previous blog we looked at installing Minikube on Windows and also on Linux. In both the cases, the software stack is the same except replacing the Linux OS with the Windows OS (highlighted above). The Container ultimately runs on Linux OS in both the cases, so only Linux Containers and not the Windows Containers can be run in case of Minikube.

How do we run a Windows Container then?

For this we have to install Docker for Windows (DFW). Instructions for installing here. Prerequisite for DFW is support for Hyper-V which is not available in Windows Home Edition, need to upgrade to a Pro edition. In DFW K8S can be enabled as mentioned here.

There are two types of Containers in the Windows world, Windows Containers which runs directly on Windows and shares the host kernel with other Containers. And the other type of Container is Hyper-V Container which has has one Windows Kernel per Container. Both the types of Containers are highlighted in the above diagram and are detailed here.

The same Docker Windows image can be run as both Windows Container and Hyper-V Container, but the Hyper-V container provides an extra isolation. The Hyper-V Container is as good as a Hyper-V Virtual Machine, but uses a light weight and tweaked Windows Kernel. Microsoft documentation recommends using Windows Containers for stateless and Hyper-V Containers for stateful applications.

As seen in the above diagram the Windows Container runs directly on top of the Windows Pro OS and doesn't use any Virtualization, but Hyper-V is a prerequisite for installing Docker for Windows, not sure why. If I get to know I will update the blog accordingly.

Conclusion

In this blog, we looked at a very high level on running Windows Containers. Currently, I have Windows Home and Ubuntu as dual boot setup. Since, I don't have a Windows Pro with Hyper-V enabled, I am not able to install Docker for Windows. Will get Windows updated to Pro and will write a blog on installing and using Docker for Windows. Keep looking !!!

On a side note, I was thinking about setting up an entire K8S cluster on Windows and looks for now it is not possible. The K8S documentation mentions that the K8S control plane (aka master components) have to be installed on a Linux machine. But, Windows based worker nodes can join the K8S cluster. Maybe down the line, running an entire K8S cluster on Windows will be supported.

Note : Finally I was able to upgrade my Windows Home to Professional (here),  enable Hyper-V (here) and installed Docker for Windows (here).