Kubernetes 1.13 Improves Cloud-Native Storage Features

The fourth release of the Kubernetes container orchestration platform in 2018 is highlighted by the general availability of kubeadm management and the Container Storage Interface features.

Microsoft Kubernetes Components

Kubernetes 1.13 was released on Dec. 3, providing users of the popular open-source cloud-native platform with new features to make it easier to manage, deploy and operate containers in production.

Among the features that are now generally available in Kubernetes 1.13 is the kubeadm administration tool for configuring services. The Container Storage Interface is another new generally available feature, providing a stable abstraction layer for different third-party storage plug-ins. Additionally, with Kubernetes 1.13, CoreDNS is now the default DNS (Domain Name Server) technology, replacing KubeDNS.

"One of the main themes that we tried to align the cycle with was around stability, that is focusing more on giving users a reliable and stable end-of-year refresh of capabilities, mostly focusing on graduating long-term outstanding features that have had time to mature," Aishwarya Sundar, release lead for Kubernetes 1.13 and Google software engineer, told eWEEK. "We also focused this release on improving the reliability of features that are already in general availability, fixing any long-term issues that might be out there." 

Kubernetes 1.13 is the fourth and final release of 2018 for the Kubernetes project and follows the 1.12 release that became generally available on Sept. 27, Kubernetes 1.11, which was released on June 27, and Kubernetes 1.10, which launched on March 26. Kubernetes is a container orchestration and cloud-native application infrastructure platform that was originally developed by Google and has been operated as a Cloud Native Computing Foundation (CNCF) project since July 2015.

Sundar noted that the 1.13 release had the shortest development cycle of any Kubernetes release. Although it was a quick development cycle, she said the new release team models and approaches expedited the process.

"We made a few release process improvements as well, focusing on CI/CD [Continuous Integration/Continuous Deployment] signals and triaging breaking changes early on in the cycle and also tightening the criteria for test jobs that block the release," she said. "All of these were non-user facing improvements that we did in terms of the release process itself to ensure that we can land a stable, reliable release on time."


The Container Storage Interface (CSI) had been in development for almost a year and first appeared as a beta feature for Kubernetes 1.10. CSI enables third-party storage vendors to build plug-ins against the stable API. Another new storage capability that is now stable in the 1.13 release is Topology Aware Volume Scheduling, which enables Kubernetes to make intelligent decisions, while provisioning storage volumes within a Kubernetes pod.

"We have the scheduler, which provides input as to which would be the best place to provision a volume and the pod," Sundar said. "For example, if you have a multi-zone cluster, this means the volumes will get provisioned in an appropriate zone that can run within the pod, allowing administrators to easily deploy and scale stable workloads."

Overall, Topology Aware Volume Scheduling enables high-availability and fault-tolerant deployments, she said.


Kubeadm is also a feature that had been in development for multiple releases of Kubernetes and is now finally generally available. Kubeadm can used as an easy cluster management tool as a well as a tool to track the creation, configuration and upgrade of Kubernetes cluster, according to Sundar. After taking user feedback, fixing bugs and making many improvements, kubeadm is now stable and ready to become generally available, she said.

What's Next?

There are a number of alpha and beta features in Kubernetes 1.13 that provide glimpses into future capabilities. Among the beta features is Kubectl Diff, which shows the difference between a locally declared object configuration and the current state of a live object. The APIServer DryRun is another capability that has landed as a beta feature.

"The API server dry run is one of the things which will help us fix a lot of existing bugs that are elusive today, with applied commands being managed within kubectl and not with an API server," Sundar said. 

In terms of alpha features making their debut, Kubernetes 1.13 introduces support for third-party device monitoring plug-ins.

"The main advantage of this feature is it will enable cluster administrators to gather more container-level metrics for devices and provide device vendors the ability to provide device-specific metrics," she said.

Sean Michael Kerner is a senior editor at eWEEK and InternetNews.com. Follow him on Twitter @TechJournalist.

Sean Michael Kerner

Sean Michael Kerner

Sean Michael Kerner is an Internet consultant, strategist, and contributor to several leading IT business web sites.