Scaling GitHub Actions To the CNCF
Talkat Open Source Summit Japan + AI_dev: Open Source GenAI & ML Summit + Automotive Linux Summit 2025 · 2025-12-08..12-10·
summary
CNCF runs 235 GitHub-hosted projects and reports ~200 million free Actions minutes in 2025, hitting concurrency limits (1500 allowed, ~844 active). After June–Dec 2024 donations change, the foundation moves from GitHub runners to self-hosted solutions using the GitHub Actions Runner Controller, Argo for deployments and Oracle Cloud for clusters, then builds a small Go utility named gha-runner-vm to spawn VM-backed runners because GitHub’s published images target VMs not containers. The system works for months but adds maintenance, caching and VM lifecycle headaches.
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chapters (16)
- 0:00Introduction
- 1:08CNCF scaling challenges
- 5:01Why GitHub Actions
- 8:27Self-hosted runners shift
- 9:33Runner Controller explained
- 14:14Deploying on Oracle Cloud
- 15:19Complex CI workflow problems
- 17:30VM versus container mismatch
- 19:39Custom VM images
- 22:55Parity with hosted runners
- 24:20Service maintenance at scale
- 26:29Monitoring and alerting
- 27:35Fixing VM issues
- 28:59Current state and onboarding
- 31:05Lessons learned
- 32:30Q&A
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