Incident Library
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Cases2 cases

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  1. IL-0233 A VPC control plane release broke IP alias routes in Nebius eu-west1, and Managed Kubernetes pods lost connectivity
    Nebius2025
    Symptoms

    On 13 March 2025 practically every pod of Nebius Managed Services for Kubernetes in the eu-west1 region lost network connectivity for at least some time between 13:36 and 18:11 UTC. Packets for the affected IP alias routes were not processed by the data plane. The eu-north1 region was not affected.

    Network unreachable
    Trigger

    A release of a VPC control plane component in eu-west1, deployed to canaries from 13:36 UTC and to all other nodes from 14:35 UTC, changed route distinguisher values for a new feature. The change made a long-standing bug in the handling of route announcements take effect for the update messages of Managed Kubernetes pods.

    Root cause
    Software defect
    Component
    Network control plane (SDN)BGP routing
    Contributing factor
    Ineffective rollbackGap in automated testsMonitoring blind spot
    Remediation
    • Restarted the host VPC component on the affected nodes one node at a time
    • Restarted the host VPC component on the remaining nodes in parallel once the restart was known to fix the problem
    Action items
    • Fix the bug in the VPC host component itself
    • Add an alert on a diverging number of routes
    • Add an alert on the number of drops in the data plane
    • Develop a way to reset endpoints without restarting the host VPC component
    • Move the VPC's persistent e2e test virtual machines to canary hosts
    • Add persistent e2e tests for Managed Services for Kubernetes
    • Run e2e tests more often
    • Add a deployment stage in which non-critical internal services receive updates first
    Lessons

    The failure needed both an existing IP alias at release time and a particular order of node updates, and neither the testing installation nor the canaries met both, so neither caught it. Missing alerts on technical metrics that deviate from normal, here the number of routes and the number of drops, made the response much slower.

    View case
  2. IL-0347 About 25% of Scaleway FR-PAR-1 hypervisors lost VPC connectivity when both VPC BGP route reflectors got stuck
    Scaleway2024
    Symptoms

    On 18 October 2024, from 7:50 to 8:01 UTC, about 25% of the hypervisors in Scaleway's FR-PAR-1 availability zone lost VPC connectivity with the rest of the region, and products that use VPC failed with them. Public internet connectivity and Elastic Metal VPC connectivity were not affected.

    Network unreachablePacket lossNode NotReady
    Trigger

    At 6:20 UTC a Top of Rack switch in FR-PAR-1 had a software crash. One of the two BGP route reflectors for VPC ran on a hypervisor in that rack and was left in an abnormal state.

    Root cause
    Software defect
    Component
    Network control plane (SDN)BGP routingNetwork switchDatabaseManaged Kubernetes control plane and provider API
    Contributing factor
    Excessive blast radiusAutomation amplification
    Detection

    Health-check monitoring on both route reflectors detected the anomaly, and the Scaleway Customer Excellence and SRE teams detected the customer impact and opened an incident.

    Remediation
    • Fixed both VPC route reflectors by manual action
    Action items
    • Fixed the autohealing mechanism that had failed to fix route reflectors stuck in a stale state; the fix is https://github.com/FRRouting/frr/pull/17163
    • Run different software versions on the route reflectors so a single bug cannot stop several instances
    • Investigate the software issue that left the route reflectors in a stale state
    View case
Check your cluster for this

These 2 cases involve BGP routing and Network control plane (SDN). 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

Software defect2 cases

Component
BGP routing2Network control plane (SDN)2Database1Managed Kubernetes control plane and provider API1Network switch1
Contributing factor
Automation amplification1Excessive blast radius1Monitoring blind spot1Ineffective rollback1Gap in automated tests1
Organisation
Nebius1Scaleway1
  1. IL-0233 A VPC control plane release broke IP alias routes in Nebius eu-west1, and Managed Kubernetes pods lost connectivity
    Nebius2025
  2. IL-0347 About 25% of Scaleway FR-PAR-1 hypervisors lost VPC connectivity when both VPC BGP route reflectors got stuck
    Scaleway2024