2022-04-06: uncontrolled HPA resizing caused by a GCP incident

Incident DRI

Current Status

For ~2 min, we were responding to most of the requests on all services with errors. image

Summary for CMOC notice / Exec summary:

  1. Customer Impact: for ~2 mins, majority of requests were failing
  2. Service Impact: all services running in GKE
  3. Impact Duration: 07:56:00 - 07:58:00 (2min)
  4. Root cause: GCP incident. Investigation issue - https://gitlab.com/gitlab-com/gl-infra/reliability/-/issues/15569

Timeline

Recent Events (available internally only):

All times UTC.

2022-04-06

  • 07:55:45 - pods in all k8s clusters start failing readiness checks
  • 07:56 - HAProxy errors start, cpu utilization on primary and replicas starts to drop
  • 07:57:00 - cpu utilization on primary and replias reaches bottom and starts to go up, total sum of db duration on replicas goes up
  • 07:57:30 - number of pods starts to go up above the previous number
  • 07:58:00 - cpu utilization on primary and replicas reaches similar levels from before the incident
  • 07:59:30 - number of pods reaches peak, roughly ~50% above what was before the incident
  • 08:01 - @mwasilewski-gitlab declares incident in Slack.
  • 08:08 - number of pods drops to the level from before the incident

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Incident Review
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Customer Impact

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What were the root causes?

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Incident Response Analysis

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Post Incident Analysis

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What went well?

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Guidelines

Resources

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Edited by Kennedy Wanyangu