Incident Library
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  1. IL-0086 A deployment meant for a CircleCI test Kubernetes cluster also removed Traefik and Calico resources from the production cluster, taking down the CircleCI UI and runner.circleci.com
    CircleCI2021
    Symptoms

    At 15:35 EST on 11 March 2021 the CircleCI web UI and runner.circleci.com became unavailable. The API, which uses a separate ingress point, stayed reachable, and builds kept running.

    Service outageResources deleted
    Trigger

    An update deployed to a test Kubernetes cluster also removed Traefik and Calico resources from CircleCI's primary production cluster.

    Root cause
    Faulty deployment
    Component
    Ingress controllerCalico
    Contributing factor
    Excessive blast radiusNo runbookMonitoring blind spot
    Detection

    CircleCI engineers were alerted and began investigating. The status page posted its first notice at 20:45 UTC.

    Remediation
    • restored Traefik in the production cluster
    • restored Calico in the production cluster, after which pods served customer requests again
    Action items
    • Improve network-level documentation and runbooks to cover every layer of the Kubernetes networks
    • Improve monitoring and alerting for the network infrastructure
    • Add guardrails that isolate the production and staging clusters so they cannot interfere with each other
    Lessons

    A deployment path that can reach both a test cluster and production can remove shared networking components from production. When the ingress controller and the CNI are both affected, restoring the ingress alone is not enough: engineers had to find the link between Calico and Traefik and restore Calico before pods served traffic again. Time went to DNS and AWS red herrings because nothing linked the outage to the test deployment; CircleCI's answer is better network runbooks, network alerting and guardrails between clusters.

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Check your cluster for this

This case involves Calico and Ingress controller. 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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By root cause1

Faulty deployment1 case

Component
CalicoIngress controller
Contributing factor
Excessive blast radiusMonitoring blind spotNo runbook
Organisation
CircleCI
  1. IL-0086 A deployment meant for a CircleCI test Kubernetes cluster also removed Traefik and Calico resources from the production cluster, taking down the CircleCI UI and runner.circleci.com
    CircleCI2021