Cases2 cases

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1. IL-0471 GitHub Actions runs failed or sat queued for 9 hours after a routine deployment's pod replacement saturated capacity

   GitHub2026

   Symptoms

   From 15:05 UTC on 6 August 2026 GitHub Actions workflow runs failed to start, failed partway through or stayed queued for a long time, on both GitHub-hosted and self-hosted runners. Some requests to the Actions REST API returned errors, and some customers saw unexpected rate limiting in their workflows.

   High error rateHigh latency

   Trigger

   A routine deployment to an internal Actions service that processes events and generates Actions jobs replaced pods, and the remaining capacity became saturated.

   Root cause

   Capacity exhaustion

   Component

   CI system

   Contributing factor

   No headroomExcessive blast radiusHarmful manual action

   Remediation

   • Expanded capacity of the affected services
   • Throttled incoming webhook-triggered work
   • Increased processing capacity for the backlog of affected events
   • Deployed changes that stopped runners from repeatedly trying to acquire invalid jobs
   • Deployed a fix for self-hosted runners that were not picking up jobs and enabled it incrementally
   • Paused migrations with GitHub Enterprise Importer
   • Restored webhook-triggered Actions workflows to full throughput
   • Rolled back the mitigation that left some ARC runners offline, and recovered those runners by hand
   • Shared CLI and UI steps for customers to clear jobs that could not be retried or canceled

   Action items

   • Improve deployment and capacity safeguards for the affected services
   • Strengthen monitoring for the conditions that preceded the incident
   • Improve the resiliency and recovery of queued work and runner assignment
   • Add automatic recovery for self-hosted runners in upcoming Runner and ARC releases
   • Reduce the risk of cascading failures and speed up recovery during large Actions disruptions

   View case
2. IL-0552 CircleCI's archival database ran out of storage, slowing workflow and job starts and the display of workflows in the UI

   CircleCI2025

   Symptoms

   At about 23:00 UTC on 21 January 2025, an automated alert reported that the CircleCI database instance holding archived data was almost out of free storage space. From 23:50 UTC customers saw slow starts and cancellations of workflows and jobs, and delays and difficulty viewing workflows in the CircleCI UI, although pipelines for a specific project could still be viewed.

   High latencyIntermittent timeoutsLog floodNode disk fullCloud API rate limit exhausted

   Trigger

   A code change to a function in the archival database on 16 January 2025 unintentionally made it write an excessive number of log messages, and the database filled its storage.

   Root cause

   Faulty deployment

   Component

   DatabaseCI system

   Contributing factor

   Change with a delayed effectExcessive blast radiusOverlapping failures

   Detection

   An automated alert at about 23:00 UTC warned that the archival database was almost out of free storage, before customers were affected. The growing workflows queue was not linked to it at first because a separate alert about request volume fired at about the same time.

   Remediation

   • Scaled up the event consumer that processes the workflows queue at 23:44 UTC
   • Promoted a read replica of the archival database to a standalone primary at 23:55 UTC

   Action items

   • Fix the database function so it no longer writes an excessive number of log messages
   • Add a max duration to the workflows retry policy for archiving so it fails earlier than the default timeout
   • Move workflow archival to an event-based model that decouples it from the workflows service
   • Add forecast and anomaly monitoring for databases that alerts on unusual activity before it reaches critical levels

   Lessons

   The storage alert on the archival database did fire, but the database filled much faster than forecast, so there was little time to act before customers were affected. Because the workflows service called the archival service synchronously, a problem in the archival database slowed the whole workflows service.

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