Merge pull request #51447 from haircommander/4033-ga-blog

Add blog for KEP 4033 GA

Author: k8s-ci-robot

content/en/blog/_posts/2025-0X-XX-Auto-Node-Configuration-Goes-GA.md

@@ -0,0 +1,50 @@
+---
+layout: blog
+title: "Kubernetes 1.34: Autoconfiguration for Node Cgroup Driver Goes GA"
+date: 2025-0X-XX
+draft: true
+slug: cri-cgroup-driver-lookup-now-GA
+author: Peter Hunt (Red Hat), Sergey Kanzhelev (Google)
+---
+
+Historically, configuring the correct cgroup driver has been a pain point for users running new
+Kubernetes clusters. On Linux systems, there are two different cgroup drivers:
+`cgroupfs` and `systemd`. In the past, both the [kubelet](/docs/reference/command-line-tools-reference/kubelet/)
+and CRI implementation (like CRI-O or containerd) needed to be configured to use
+the same cgroup driver, or else the kubelet would misbehave without any explicit
+error message. This was a source of headaches for many cluster admins. Now, we've
+(almost) arrived at the end of that headache.
+
+## Automated cgroup driver detection
+
+In v1.28.0, the SIG Node community introduced the feature gate
+`KubeletCgroupDriverFromCRI`, which instructs the kubelet to ask the CRI
+implementation which cgroup driver to use. You can read more [here](/blog/2024/08/21/cri-cgroup-driver-lookup-now-beta/).
+After many releases of waiting for each CRI implementation to have major versions released
+and packaged in major operating systems, this feature has gone GA as of Kubernetes 1.34.0.
+
+In addition to setting the feature gate, a cluster admin needs to ensure their
+CRI implementation is new enough:
+
+- containerd: Support was added in v2.0.0
+- CRI-O: Support was added in v1.28.0
+
+## Announcement: Kubernetes is deprecating containerd v1.y support
+
+While CRI-O releases versions that match Kubernetes versions, and thus CRI-O
+versions without this behavior are no longer supported, containerd maintains its
+own release cycle. containerd support for this feature is only in v2.0 and
+later, but Kubernetes 1.34 still supports containerd 1.7 and other LTS releases
+of containerd.
+
+The Kubernetes SIG Node community has formally agreed upon a final support
+timeline for containerd v1.y. The last Kubernetes release to offer this support
+will be the last released version of v1.35, and support will be dropped in
+v1.36.0. To assist administrators in managing this future transition,
+a new detection mechanism is available. You are able to monitor
+the `kubelet_cri_losing_support` metric to determine if any nodes in your cluster
+are using a containerd version that will soon be outdated. The presence of
+this metric with a version label of `1.36.0` will indicate that the node's containerd
+runtime is not new enough for the upcoming requirements. Consequently, an
+administrator will need to upgrade containerd to v2.0 or a later version before,
+or at the same time as, upgrading the kubelet to v1.36.0.