Cases3 cases

1 to 3 of 3

1. IL-0234 An onboarding operator deployed without its scope file installed dev applications on other IONOS Kubernetes clusters

   IONOS Cloud2026

   Symptoms

   On 8 May 2026 IONOS Cloud reported "K8s Control Planes not available": some Managed Kubernetes customers in DE/TXL, DE/FRA and DE/FRA/2 had trouble connecting to the control plane and saw degraded Kubernetes functionality. Between 15:22 and 16:12 (UTC+2) applications meant for a new internal development cluster were installed on other customer clusters, which were also modified.

   Control plane unresponsiveImage pull failures

   Trigger

   A routine internal operation onboarded a new Managed Kubernetes development cluster. The scoping configuration file for the onboarding operator failed to reach the deployment branch because of a merge conflict, and at the same time a second change removed the operator from the exclusion list, which deployed it at once.

   Root cause

   Faulty deployment

   Component

   CI systemContainer registry and its credentials

   Contributing factor

   No configuration testsExcessive blast radiusMissed in review

   Remediation

   • Corrected the onboarding operator so it needs an explicit namespace configuration before acting on any cluster
   • Reconfigured the deployment system to fail deployments when required configuration files are missing
   • Rolled back the identified changes on the affected resources
   • Ran a recovery script, validated in staging, that removed all unintended installations and updates from the affected clusters

   Action items

   • Add a mandatory CI/CD step that confirms all required configuration files reached the target branch before any deployment starts
   • Require additional peer review and change management approval for every deployment that touches production, whatever its size
   • Give teams a way to inform each affected customer in time about the status of post-incident cleanup

   Lessons

   IONOS treats the unintended change to cluster configurations as a failure of the controls that should keep internal operations from affecting customer environments.

   View case
2. IL-0315 Railway's backend API went down when an index build locked a billion-row Postgres table and used up every connection

   Railway2025

   Symptoms

   At 18:36 UTC on 28 October 2025, two minutes after a database change went live in production, Railway's internal monitoring alerted and paged the engineering team. The dashboard could not be opened, CLI operations that use the API, such as railway up, failed, GitHub-based deployments were delayed because webhook processing failed, and all Railway Public API operations were disrupted.

   Service outageLock contention or deadlockDatabase overload

   Trigger

   A routine schema change to the backend's Postgres database, introduced at 18:23 UTC and live in production at 18:34 UTC, that added a new column with an index without the CONCURRENTLY option.

   Root cause

   Faulty deployment

   Component

   DatabaseDatabase proxy and connection pooler

   Contributing factor

   No configuration testsLimited debug access

   Detection

   Internal monitoring alerts paged the engineering team at 18:36 UTC, and the incident was declared at 18:41 UTC.

   Remediation

   • The index migration finished after about 30 minutes and released the table lock, and the queued operations and connection pools recovered

   Action items

   • Enforce CONCURRENTLY for all index creation in CI and block pull requests that do not use it
   • Adjust PgBouncer pool limits so they cannot overwhelm the Postgres instance's capacity
   • Configure database user connection limits so administrative access stays possible during incidents

   View case
3. IL-0554 A database migration used up Sentry US's Postgres connections, and the site and event ingestion were down for 22 minutes

   Sentry2024

   Symptoms

   From 3:42 PM to 4:04 PM PT on 10 October 2024, the Sentry US site and event ingestion were unavailable, and the status page reported an issue with the Postgres database that made the site unavailable. The dashboard, the API and every US ingestion type, including errors, transactions, attachments, profiles, replays, spans, cron monitoring and custom metrics, were affected.

   Service outageDatabase overload

   Trigger

   A database migration ran certain database operations through the RunSQL command without lock and statement timeouts.

   Root cause

   Faulty deployment

   Component

   DatabaseSchema migration

   Contributing factor

   No configuration testsNo runbook

   Remediation

   • Issued a fix, after which the dashboard and ingestion recovered

   Action items

   • Replace RunSQL commands with more robust solutions in the migration framework
   • Update the database framework to the latest version, which handles some operations RunSQL was used for
   • Write runbooks for recovering from lock or timeout issues during migrations
   • Improve alerting and observability so the team reacts sooner

   View case

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