Incident Library
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  1. IL-0221 A backbone maintenance command disconnected all Facebook data centers, and its DNS servers withdrew their BGP routes
    Meta2021
    Symptoms

    On 4 October 2021 Facebook's platforms went down worldwide: every connection in Facebook's global backbone network was lost, and the data centers were cut off from each other and from the internet. The rest of the internet could no longer find Facebook's servers, because Facebook's authoritative DNS servers had become unreachable.

    Service outageDNS resolution failuresNetwork unreachable
    Trigger

    During routine maintenance of the backbone, a command was issued to assess the availability of global backbone capacity, and it unintentionally took down all connections in the backbone network.

    Root cause
    Operator error
    Component
    Backbone network (WAN)BGP routingAuthoritative DNS servers and records
    Contributing factor
    Automation amplificationCircular dependencyLimited debug access
    Remediation
    • Sent engineers onsite to the data centers to debug the issue and restart systems
    • Brought the backbone network back online across the data center regions
    • Brought services back gradually, managing the rising load to avoid crashes from a traffic surge
    Action items
    • Find ways to simulate the global backbone being taken offline in storm drills
    • Strengthen testing, drills and overall resilience
    Lessons

    The hardening that protects Facebook's data centers against unauthorized access slowed recovery from an outage caused by Facebook's own error, and the author judges that tradeoff worth keeping. Storm drills prepared the teams to bring load back safely, although no drill had yet simulated the global backbone going offline.

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Check your cluster for this

This case involves Backbone network (WAN) and BGP routing. 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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Operator error1 case

Component
Backbone network (WAN)BGP routingAuthoritative DNS servers and records
Contributing factor
Automation amplificationCircular dependencyLimited debug access
Organisation
Meta
  1. IL-0221 A backbone maintenance command disconnected all Facebook data centers, and its DNS servers withdrew their BGP routes
    Meta2021