Kubernetes 1.9 became generally available on Dec. 15, marking what is the final release of 2017 for the open-source container orchestration system. Kubernetes 1.9 is the fourth major release of Kubernetes in 2017 and follows the 1.8 release that became generally available on Sept. 28.
Among the new features in Kubernetes 1.9 is the general availability of the Apps Workloads API, which is the culmination of months of effort across several groups of APIs within Kubernetes.
"The Apps Workloads API groups the DaemonSet, Deployment, ReplicaSet, and StatefulSet APIs together to form the foundation for long-running stateless and stateful workloads in Kubernetes," the Kubernetes 1.9 release announcement states.
The Stateful Set API was first previewed as a beta feature in the Kubernetes 1.5 release that debuted in December 2016. The feature in alpha was known as PetSet, and it serves as the cornerstone of APIs that enables long-running stateful application deployment in Kubernetes.
Without StatefulSet and the broader Apps Workloads API, it was more difficult for Kubernetes users to define and deploy a stateful set of services to enable long-running application workloads.
Container Storage Interface
The Kubernetes 1.9 release also marks the alpha debut of the new Container Storage Interface (CSI) specification.
Much like the Container Networking Interface (CNI) provides a vendor-neutral abstraction for different networking overlay technologies, the CSI provides an abstraction for different storage technologies to plug into Kubernetes.
"Container Storage Interface (CSI) is a cross-industry standards initiative that aims to lower the barrier for cloud-native storage development and ensure compatibility," the Kubernetes 1.9 release stated. "SIG-Storage and the CSI Community are collaborating to deliver a single interface for provisioning, attaching, and mounting storage compatible with Kubernetes."
Kubernetes was originally a Google project and Google still remains the top code contributor to the project, according the Cloud Native Computing Foundation's (CNCF) devstats tracker. Red Hat, Huawei, CoreOS, IBM and Microsoft are now all active contributors as well.
Sean Michael Kerner is a senior editor at ServerWatch and InternetNews.com. Follow him on Twitter @TechJournalist.