What is the new cgroup v2 CPU weight formula for Kubernetes?

It's a quadratic map hitting (2,1), (1024,100), (262144,10000) – implemented in runc 1.3.2+ and crun 1.23+.

Will cgroup v1 to v2 conversion break my Kubernetes cluster?

Unlikely for most – but monitoring/tools assuming linear math need fixes. Test post-upgrade.

How do I check if my runtime uses the new formula?

Runc --version or crun --version; look for 1.3.2+ / 1.23+. Inspect pod cgroups via crictl.

Kubernetes' cgroup v2 CPU Fix: Quadratic Magic or Half-Measure?

Picture your Kubernetes pods gasping for CPU cycles, starved by a botched conversion formula. OCI runtimes just dropped a quadratic fix – better, but not without pitfalls.

Open Source Beat Apr 07, 2026 3 min read

Graph comparing old linear and new quadratic cgroup v1 shares to v2 weight conversion curves

⚡ Key Takeaways

New quadratic formula fixes CPU priority loss and granularity issues in cgroup v2 transitions. 𝕏
Implemented at OCI runtime level (runc/crun), not Kubernetes core – fast adoption possible. 𝕏
Watch for breakage in tools hardcoding old linear weights; test thoroughly. 𝕏

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Open Source Beat

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#CPU scheduling #CPU weight conversion #Kubernetes CPU #OCI runtime #OCI runtimes #cgroup v2 #kubernetes #runc crun

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Originally reported by Kubernetes Blog

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