Incident Library
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Cases2 cases

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  1. Symptoms

    On August 16, 2024 from 11:38 AM to 1:16 PM PT, the OpenAI primary API was unreliable: ChatGPT conversations succeeded less often, and logging in and creating accounts were affected. The status page called it elevated error rates for ChatGPT and the Platform API. The incident came in two waves, of 44 and 15 minutes.

    Trigger

    A scheduled maintenance combined with an upgrade to the ingress of OpenAI's user-facing clusters.

    Root cause
    Component
    Contributing factor
    Action items
    • Mitigate the networking control plane regression and validate that control plane restarts do not interfere with the clusters' data plane
    • Change service software to start faster and remove the first-start query, relieving the persistence layer
    • Deploy configuration changes that optimise the networking control plane's effect on the clusters' ability to handle traffic
    • Remove the expensive database query from critical startup paths
    • Add monitoring and alerting for networking control plane issues
    • Introduce staged rollouts with longer soak time for infrastructure changes
    • Audit systems for other slow queries that may affect service start time
    Lessons

    A brief connectivity loss turned into a long outage because recovery itself was expensive: the services that restarted overwhelmed one backend persistence store with a heavy first-start query. Keeping costly queries off startup paths shortens recovery, and staged rollouts with longer soak time limit how many systems an infrastructure regression reaches before it is caught.

  2. Symptoms

    Standard alerting paged Honeycomb's on-call engineers about the performance and stability of event ingestion, and the automated load-shedding mechanisms tripped and sent further notifications. The status page described a higher than normal error rate and response time on the ingestion service.

    Trigger

    An abnormally large number of queries arrived from many separate connections within a few minutes.

    Root cause
    Component
    Contributing factor
    Detection

    Standard alerting notified the on-call engineers about ingestion performance and stability, and the automated load-shedding mechanisms added notifications when they tripped. The first status post, about alerts on a higher than normal error rate and response time, went up at 18:28 PST (02:28 UTC), 13 minutes after the 02:15 UTC start.

    Remediation
    • Scaled the ingest fleet up manually and aggressively
    • Cut off most ingest for a few minutes so the ingest hosts could come back with enough capacity
    • Temporarily lowered the rate limits for the most aggressive traffic sources until their traffic subsided
    Action items
    • Keep the ingest fleet scaled up to prevent a repeat while longer-term fixes are worked on
    • Decide on the projects that will address these failure paths
    Lessons

    Load shedding and auto-scaling were in place, yet a burst that arrived faster than the cache could spread its writes still took the ingest hosts down. During recovery, Kubernetes' crash loop back-off worked against the operators: the hosts that had failed stayed offline while the fleet needed every host. Clients that retry whole OTel batches after a partial drop can multiply traffic many times over, so per-source rate limits were what finally stabilised ingest.

Check your cluster for this

These 2 cases involve Application database and In-memory cache. kubegap audits a Kubernetes cluster for gaps like these, read-only, from Claude Code or Codex; its checks cite public reports like the ones in this library.

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