Kubernetes 1.9 version bump is near – with APIs to extend the system
Latest container wrangling bits should drop on Friday
Assuming a handful of lingering issues can be resolved, the open-source Kubernetes project will introduce version 1.9 on Friday.
In a phone interview with The Register, Aparna Sinha, special interest group (SIG) product management lead for Kubernetes and product manager at Google, singled out the general availability designation of the Apps/V1 Workloads API as the most notable aspect of the release.
Workloads are computing resources used to manage and run containers in a cluster. The Apps Workloads API includes DaemonSet, Deployment, ReplicaSet, and StatefulSet; it's distinct from the Batch Workloads API, which includes Job and CronJob and has yet to reach general availability.
The general availability designation (V1) signals the API is robust enough for production usage and implies long-term backwards compatibility.
DaemonSet provides a way to describe apps that operate on an ongoing basis. Deployment allows the description of an app's desired state. ReplicaSet provides the container instances to meet the Deployment configuration. And StatefulSet provides a way to maintain persistent data when containers disappear or get restarted.
"What the community has done is work on all four of these resource types and bring a level of consistency across them," said Sinha.
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These APIs, said Sinha, provide a way for companies to extend Kubernetes. "The idea is you can write a piece of code, some function, and define an API and use one of these extension mechanisms to ...make it part of Kubernetes," she said.
Anthony Yeh, a Google software engineer and the Kubernetes 1.9 release lead, said many of the newcomers to the Kubernetes community are building things on top of Kubernetes rather than contributing to the core code, which is why so much energy has been put into these extensions.
With the recent introduction of the Cloud Native Computing Foundation's Certified Kubernetes Conformance Program – a program to ensure vendor implementations of Kubernetes adhere to the spec – companies playing in the Kubernetes ecosystem will have to look beyond commodified orchestration to add value. So expect a lot of extensions.
Kubernetes is also looking to extend its footprint beyond Linux to Microsoft Windows. After about a year of work, Windows Server support in Kubernetes has advanced to beta status, meaning it's stable enough for testing.
The orchestration software has also gained an alpha implementation – it must be specifically enabled – of the Container Storage Interface, an initiative that aims to provide a standard way to connect storage systems not just to Kubernetes but to any container orchestration system, such as Docker Swarm, Mesos, or Cloud Foundry.
Initial CSI support will allow third-party storage providers to start working on Kubernetes-friendly products without touching the core code.
Another alpha feature appearing with version 1.9 is support for hardware acceleration, which will make Kubernetes better suited for machine learning and other computationally intensive workloads.
"Looking forward, we're doing a lot more support for GPUs and hardware accelerators," said Sinha. ®