2024-09-03: The sidekiq_queueing SLI of the sidekiq service on shard urgent-cpu-bound has an apdex violating SLO

Customer Impact

Background processes may take longer to be picked up and executed than usual. This can result in emails not being delivered and commits not showing up in merge request activity. CI/CD jobs may be stuck in pending state impacting user CI minutes. Duo features on gitlab.com that use Sidekiq are impacted (such as Chat).

Current Status

The impact has been mitigated and most background processes should be running as normal now (background processes to update counters are disabled). Investigations into the root cause are ongoing.

📝 Summary for CMOC notice / Exec summary:

1. Customer Impact: Features that rely on Sidekiq are degraded (such as CI jobs queuing up)
2. Service Impact: ServiceSidekiq
3. Impact Duration: 8 hours 20 minutes
4. Root cause: unknown

📚 References and helpful links

Recent Events (available internally only):

• Feature Flag Log - Chatops to toggle Feature Flags Documentation
• Infrastructure Configurations
• GCP Events (e.g. host failure)

Deployment Guidance

• Deployments Log | Gitlab.com Latest Updates
• Reach out to Release Managers for S1/S2 incidents to discuss Rollbacks, Hot Patching or speeding up deployments. | Rollback Runbook | Hot Patch Runbook

Use the following links to create related issues to this incident if additional work needs to be completed after it is resolved:

• Corrective action ❙ Infradev
• Incident Review ❙ Infra investigation followup
• Confidential Support contact ❙ QA investigation

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Security Note: If anything abnormal is found during the course of your investigation, please do not hesitate to contact security.