The most major change in this release is actually a feature that is already in widespread use. Custom Resource Definitions (CRD) are a major foundation of Kubernetes extensibility and are used by many features and projects; however, they have been in beta since version 1.7, over two years ago. They finally graduate to general availability (GA) and stable status in this release, meaning that anyone using the current version of the feature and its API can expect compatibility for any future 1.x release as well as any 2.x release yet to come.
Admission webhooks have been in beta for nearly as long, since 1.9. They, too, graduate to general availability in this release. Admission webhooks offer very fine-grained control of user permissions.
In addition, this release brings a major overhaul to Kubernetes metrics, which have been excluded previously from stability requirements. Many metrics are added, and a few are dropped.
There are many interesting developments on the alpha/beta front as well.
The Container Storage Interface (CSI) specs for volume extension move to beta in this release. And CSI spec volume plugin can now be resizable.
Enhancements have been made on the path to allow existing clusters to migrate cloud-specific control loops from the old in-tree cloud providers (under kube-controller-manager, or KCM) to the new out-of-tree providers (under cloud-controller-manager, or CCM) without downtime.
A new Topology Manager can optimize allocation of resources, keeping devices and the CPUs that need them in proximity.
Two of the most interesting areas in the alpha/beta spaces of this release are IPv4/IPv6 dual stack support and Windows containers support. These are both rapidly evolving and will greatly enhance the role of Kubernetes in modern enterprise data centers. We are, of course, tracking these closely in our product planning process.
Look for upstream version 1.16 to be available in a SUSE CaaS Platform release within about 90 days.