Incident documentation/20200412-eqiad down

document status: draft

document status: document status: draft

Summary

eqiad cluster had issues.

Impact: All users reading or editing from that cache.

See phab:T250025.

Timeline

All times in UTC.

• 05:05 Connection problems (Error: 502, Next Hop Connection Failed)
• 05:34 Issues resolved

Detection

Issue was first detected during editing en.wp, when the site failed.

Conclusions

What weaknesses did we learn about and how can we address them?

What went well?

• (Use bullet points) for example: automated monitoring detected the incident, outage was root-caused quickly, etc

What went poorly?

• (Use bullet points) for example: documentation on the affected service was unhelpful, communication difficulties, etc

Where did we get lucky?

• (Use bullet points) for example: user's error report was exceptionally detailed, incident occurred when the most people were online to assist, etc

How many people were involved in the remediation?

• (Use bullet points) for example: 2 SREs and 1 software engineer troubleshooting the issue plus 1 incident commander

Links to relevant documentation

Add links to information that someone responding to this alert should have (runbook, plus supporting docs). If that documentation does not exist, add an action item to create it.

Actionables

Create a list of action items that will help prevent this from happening again as much as possible. Link to or create a Phabricator task for every step.

• To do #1 (TODO: Create task)
• To do #2 (TODO: Create task)

TODO: Add the #Wikimedia-Incident Phabricator tag to these tasks and move them to the "Follow-up" column.