2021-01-06 web-27 puma misbehaving
Summary
web-27 lost it's ability to talk to the primary redis-cache node and initially saturated all puma threads waiting on network replies that were never received; it required a full shutdown/restart to bring it back into service.
Timeline
All times UTC.
2021-01-06
- 03:29 - Alert fires
- 03:41 - cmiskell declares incident in Slack.
- 04:15 - Solution found, server shutdown and restarted (full,not just a reboot)
- 04:18 - server returned to service.
Corrective Actions
Click to expand or collapse the Incident Review section.
Incident Review
Summary
- Service(s) affected:
- Team attribution:
- Time to detection:
- Minutes downtime or degradation:
Metrics
Customer Impact
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Who was impacted by this incident? (i.e. external customers, internal customers)
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What was the customer experience during the incident? (i.e. preventing them from doing X, incorrect display of Y, ...)
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How many customers were affected?
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If a precise customer impact number is unknown, what is the estimated impact (number and ratio of failed requests, amount of traffic drop, ...)?
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What were the root causes?
Incident Response Analysis
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How was the incident detected?
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How could detection time be improved?
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How was the root cause diagnosed?
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How could time to diagnosis be improved?
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How did we reach the point where we knew how to mitigate the impact?
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How could time to mitigation be improved?
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What went well?
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Post Incident Analysis
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Did we have other events in the past with the same root cause?
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Do we have existing backlog items that would've prevented or greatly reduced the impact of this incident?
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Was this incident triggered by a change (deployment of code or change to infrastructure)? If yes, link the issue.
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Lessons Learned
Guidelines
Resources
- If the Situation Zoom room was utilised, recording will be automatically uploaded to Incident room Google Drive folder (private)
Incident Review Stakeholders
Edited by Igor