Wednesday's release of Kubernetes v1.37 shows how the team behind the popular open-source resource orchestrator is prioritizing production readiness, pruning outdated features even while it adds new ones. Overall, the release, nicknamed Garhwal after India’s lush Himalayan region of Uttarakhand, includes 67 changes: 16 features that have graduated to stable, production-ready status, along with 23 features being tested as beta, 27 new alpha features, and 1 deprecation.
The Cloud Native Computing Foundation (CNCF), which stewards Kubernetes among more than 220 cloud native projects, has to be mindful of its user base, which may be growing out of its infatuation with the bleeding edge. Approximately 82 percent of container users run Kubernetes in production, up from 66 percent in 2023, according to a CNCF January survey. Kubernetes has also become a big driver of AI workloads, with CNCF reporting that 66 percent of organizations hosting generative AI models use Kubernetes to manage some or all of their inference workloads.
Metrics API Finally Stable One of the first rules of maintaining production software is to keep the betas moving along. This release finally bumps the Metrics API to general availability, after being in beta status for the last nine years of K8s’ 12 years of public existence. In 2020, the maintainers of the Kubernetes resource orchestration platform set down the law: Any new API-based feature must not linger in beta status for more than three Kubernetes minor releases (about 12 months in the current release cadence). After three releases, the beta must move to general availability, or be replaced by another attempt at offering the same functionality.
Despite that mandate, the Metrics API remained in beta. According to Kubernetes 1.37 Release Lead Dipesh Rawat, "Despite the Beta label, the metrics.k8s.io API has been widely used in production for years." A CNCF spokesperson noted that the organization does not interfere in the decisions of the projects under its purview. The API may have skirted the deadline because it is not managed by the API server itself but rather is an aggregated API served out-of-tree by a separate metrics server. Also, the Instrumentation Special Interest Group was busy refining the underlying performance of the metrics serving engine after replacing the previous version, Heapster.
"No functional changes [are] expected," the release notes state. "Its move into v1 in this release formally recognizes that the API has already proven itself in production, and this is simply a mature project addressing a long-standing permanent Beta status."
Cleaning House: kube-dns, IPVS, cgroup v1 Other technical debt has been addressed in this release. The software’s original built-in DNS server, kube-dns, is being retired in favor of CoreDNS, the default cluster DNS add-on since Kubernetes v1.13. Those running kube-dns must update their clusters before Kubernetes 1.40, or they will stop working. Also, word has been handed down that kube-proxy, which handles the routing amongst the pods, will no longer support the Linux IPVS (IP Virtual Servers), beginning with Kubernetes 1.43. Additionally, cgroup v1 support is being phased out, aligning with the broader Linux community's shift to cgroup v2.
These deprecations reflect a deliberate effort to reduce maintenance burden and encourage users to adopt modern, efficient components. The CNCF expects operators to plan migrations accordingly.