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  1. IL-0464 IONOS Managed Kubernetes control planes went unreachable for minutes at a time as their shared etcd grew and fragmented
    IONOS Cloud2026
    Symptoms

    From 14 to 16 March 2026 a subset of customer control planes on IONOS Managed Kubernetes (MK8s) became unavailable again and again, each time for several minutes. While a cluster was unreachable, operations that depend on the Kubernetes API, such as deployments, scaling and health checks, did not work reliably.

    Control plane unresponsiveImage pull failures
    Root cause
    Capacity exhaustion
    Component
    etcdKubernetes API serverManaged Kubernetes control plane and provider API
    Contributing factor
    Excessive blast radius
    Remediation
    • Defragmented the affected database instances, reclaiming about 3–4 GiB per instance
    • Shortened the database compaction intervals on the affected instances
    • Deployed a fix for the affected AI Model Hub database services
    • Applied final changes to all affected clusters
    Action items
    • Expand monitoring dashboards to show control plane health per database instance
    • Move the highest-volume clusters to dedicated database backends
    • Make incidents of this kind trigger immediate paging
    • Roll the updated compaction interval out to all shared control plane database instances
    • Run automated, scheduled defragmentation jobs on all instances
    • Rebalance clusters across database instances to reduce concentration
    • Contact customers whose clusters write disproportionate data, for example to store large security scan reports outside the control plane database
    • Introduce per-tenant resource quotas and key-count limits on the shared control plane database
    • Re-architect the shared control plane for stronger isolation, with dedicated database instances and better vertical scaling
    • Evaluate full database sharding for customers with consistently high data volumes
    • Hold regular drills on database resource exhaustion and recovery
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This case involves etcd and Kubernetes API server. 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

Capacity exhaustion1 case

Component
etcdKubernetes API serverManaged Kubernetes control plane and provider API
Contributing factor
Excessive blast radius
Organisation
IONOS Cloud
  1. IL-0464 IONOS Managed Kubernetes control planes went unreachable for minutes at a time as their shared etcd grew and fragmented
    IONOS Cloud2026