The open-source Kubernetes container management system is moving forward with the release of Kubernetes 1.5 on December 15, bringing the platform to Microsoft Windows Server for the first time. The Kubernetes 1.5 milestone is the last major release of Kubernetes in 2016 and follows the 1.4 release that debuted on September 26.
The Kubernetes project is part of the Linux Foundation's Cloud Native Computing Foundation (CNCF), and is supported by multiple vendors that are building and contributing code.
"Kubernetes is gaining traction as the standard open source platform enabling deployments across public, private, hybrid, and multi-cloud environments," Dan Kohn, executive director, The Cloud Native Computing Foundation said.
Among the vendors that helped with the Windows support in Kubernetes 1.5 are Red Hat and Apprenda.
"Red Hat has helped enable the Windows container support at several levels, including laying foundational groundwork to have Windows nodes connected to the cluster and assisting in the prototyping of how Kubernetes concepts can be mapped to Windows containers," Clayton Coleman, lead engineer for OpenShift at Red Hat, told eWEEK. "While this effort is still in its early days, we are excited about the potential to manage mixed application workloads on Kubernetes across both Windows and Linux."
Prior to the Kubernetes 1.5 release, Linux was the only supported operating system. Rakesh Malhotra, Senior Vice President of Products and Engineering at Apprenda explained that Kubernetes had previously been supported on the Microsoft Azure cloud, but without Windows Server support. Kubernetes is now coming to Windows Server 2016, thanks to the fact that it is the first version of Windows with container support. Microsoft and Docker Inc. announced Docker container support on September 26.
"With the 1.5 release of Kubernetes, you can install a hybrid container host environment of Linux and Windows Server operating systems to host your Kubernetes cluster, with everything deployed in your local infrastructure or in Microsoft Azure," Malhotra told eWEEK.
Malhotra explained that with Kubernetes 1.5, applications can run on either Linux or Windows Server. However, the actual containers, for example, Windows Server and Hyper-V containers, are only capable of being distributed across Windows Server nodes in the cluster. For developers, the API of both the Windows and Linux side will continue to look the same. Malhotra added that all Kubernetes environments will continue having a requirement to deploy Linux nodes to host the Kubernetes master components including the API server, controller manager, scheduler and distributed storage. The Kubernetes nodes that are the container hosts can be deployed using Windows Server or Linux.
"Kubernetes should be a single control plane that developers can simply deploy to and have DevOps or operations decide which operating system is best," Malhotra said.
Malhotra added that the Windows support is real code, though there is still work to do on the networking front before it becomes generally available for production workloads.
Another feature that is part of the Kubernetes 1.5 milestone is the StatefulSet capability which is now in Beta.
"StatefulSet, which used to be called PetSet, allows organizations to run stateful applications," Malhotra said.
Malhotra noted that stateful applications are applications that requires a greater sense of identity and persistence in storage, which would include databases like PostgreSQL and clustered software like distributed key-value stores or Cassandra.
Looking forward to 2017, there are a number of areas where Kubernetes is likely to improve. Malhotra said that Apprenda will continue working side by side with Microsoft to enhance the networking backbone of Windows Server Containers. Additionally, he expects to see continued innovation on the Kubernetes dashboard as well as bare metal deployment advancements.
Coleman commented that Red Hat is focusing on ensuring that Kubernetes has a vibrant ecosystem and can be allowed to continue to grow in many different areas.
"A key enabler will be making the platform more modular and extensible," Coleman said. "We have been working for quite a while to ensure that Kubernetes can be the core of a cluster operating system and we're just scratching the surface of how users can customize Kubernetes to meet their needs."
Sean Michael Kerner is a senior editor at eWEEK and InternetNews.com. Follow him on Twitter @TechJournalist