Since Windows worker node support reached GA in Kubernetes Microsoft and Tigera have listened closely to feedback from the community. A big contention point of Windows Container users in the Kubernetes community is: “One of the most important open source network policy tools in the market is not available for Windows.” This is limiting adoption of Windows worker nodes for Kubernetes in environments big and small as customers cannot fulfill their policy and compliance requirements like they could address them in Linux.
Over the last couple of years Microsoft and Tigera have been working together to close some significant gaps in the Windows container networking stack. The work includes enabling Direct Server Return, enhanced policy, packet logging, expanded firewall support in the Host Networking Service of Windows, multi-subnet support and many more large and small improvements.
Now for the good news:
We are incredibly happy to share that with Calico 3.16 - Windows container support is now GA in open source Calico (Release Notes)
With this release, windows containers can be deployed and secured in Azure cloud, any other cloud computing provider or on-premises using networking components in Windows Server and Calico network policy.