Incident with Actions

On August 26, 2026 from 15:02 to 15:45 UTC, Actions jobs failed to start. The following 2 hours until 17:40 UTC, Actions runs were delayed starting by more than 5 minutes as the system caught up with delayed load. This impact was triggered by saturation of writes to the database primary used by the service processing triggers for Actions workflows. The primary was failed over, but the system did not fully recover. The saturation was caused by growing daily peak load combined with an upstream issue in GitHub’s event processing infrastructure, https://www.githubstatus.com/incidents/hcbtzksccj2f, which caused burst amplification of already-high load. Downstream throttles that were later used to recover were set ~10% too high to protect the system. At 15:45 UTC, throttling combined with service restarts recovered the service’s core health. Those throttles were gradually raised between 15:54 and 17:22 to restore full webhook processing for Actions runs. This ramp was deliberately slow to ensure we did not re-overwhelm the system given our original throttling was now known to be incorrectly set. The queue of webhook events was fully burned down at 17:40 UTC. 3.7% of larger-runner jobs, along with some scale-set self-hosted jobs, remained stuck in queued or “waiting for runner” state. We deployed a change to force-revoke jobs in this state, and they transitioned to failed at 18:40 UTC, about 50 minutes after incident mitigation. Releasing these jobs also freed hosted concurrency for larger-runner jobs. Customers using concurrency groups saw longer impact due to a separate issue w…

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