2024-02-14: Redis client connection intermittent saturation
Customer Impact
The customers impact is resolved now that the revert MR has merged and was deployed.
Current Status
This issue is resolved now that MR, Revert Redis v5 gem upgrade (gitlab-org/gitlab!144770 - merged), which reverts a problematic redis gem upgrade, has landed on gprd-cny.
Summary
- Multiple redis dbs were showing client connection errors.
- As a mitigation, the file descriptor max
maxclients
was bumped from 40k to 49k in the runtime config for redis nodes to allow more breathing room for connections. The hard-coded limit for redis DB instances managed by omnibus is 50k. - It was determined that a redis gem upgrade which was recently merged caused an increase in redis connections. A revert MR was opened to resolve this issue.
- We bumped the severity of the event from severity3 to severity2 to block deployments while the revert MR is merged and deployed to gprd-cny.
More information will be added as we investigate the issue. For customers believed to be affected by this incident, please subscribe to this issue or monitor our status page for further updates.
📚 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
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- Corrective action ❙ Infradev
- Incident Review ❙ Infra investigation followup
- Confidential Support contact ❙ QA investigation
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