Incidents/2023-09-20 mw-page-content-change-enrich

== Summary ==
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The mw-page-content-change-enrich (flink) app is failing to start in eqiad (passive DC because of a network timeout on a dependent service (thanos-swift) https://logstash.wikimedia.org/goto/ce1765e186329ed74f179d375f8df182.
The app needs swift for HA. The connection failure caused the k8s operator to fail startup. The incident was caused by incorrect egress rules. Since the app is DC agnostic, egress rules must be set for both DCs ip ranges for all deployments.
This issue was fixed by applying the proper egress rules, a re-deploying the application. The active DC deployment was not affected.
==Timeline==
All times in UTC.
*2023-09-19 15:00:00 alerts fire
*2023-09-20 09:10:05 gehel escalates to gmodena (#wikimedia-analytics). Troubleshooting starts.
*2023-09-20 09:42:23 issue is identified
*2023-09-20 09:46:14 triage with claime (#wikimedia-data-persistence), patch is prepared for review
*2023-09-20 12:00:00 patch has been deployed 
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There was no user visible outage.
==Detection==
Alerts where fired based on prometheus metrics. 
The issue was escalated to the DRI.
==Conclusions ==
* there was no user visible outage.
* only passive DC was affected.
* mw-page-content-change-enrich egress rules to thanos were misconfigured.
* we never encountered this issue before, because swift-thanos was pooled in both eqiad and codfw.
* during DC switchover swift-thanos was depooled from eqiad.
* the network route issue manifested.
===What went well?===
* gehel was proactive in escalating the incident to the DRI.
* instrumentation and logs supported troubleshooting.
* claime (#wikimedia-data-persistence) promptly helped to triage the issue.
===What went poorly?===
* lead time to escalation could have been shorter.
* Early critical alerts went unnoticed by the application DRIs.
===Where did we get lucky?===
* …
OPTIONAL: (Use bullet points) for example: user's error report was exceptionally detailed, incident occurred when the most people were online to assist, etc
==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.
Add the #Sustainability (Incident Followup) and the #SRE-OnFire Phabricator tag to these tasks.
==Scorecard==
Incident Engagement ScoreCard
 	Question 	Answer
(yes/no)	Notes
People 	Were the people responding to this incident sufficiently different than the previous five incidents? 		
People 	Were the people who responded prepared enough to respond effectively 		
People 	Were fewer than five people paged? 		
People 	Were pages routed to the correct sub-team(s)? 		
People 	Were pages routed to online (business hours) engineers?  Answer “no” if engineers were paged after business hours.		
Process 	Was the "Incident status" section atop the Google Doc kept up-to-date during the incident? 		
Process 	Was a public wikimediastatus.net entry created? 		
Process 	Is there a phabricator task for the incident? 		
Process 	Are the documented action items assigned? 		
Process 	Is this incident sufficiently different from earlier incidents so as not to be a repeat occurrence? 		
Tooling 	To the best of your knowledge was the open task queue free of any tasks that would have prevented this incident? Answer “no” if there are
open tasks that would prevent this incident or make mitigation easier if implemented.		
Tooling 	Were the people responding able to communicate effectively during the incident with the existing tooling? 		
Tooling 	Did existing monitoring notify the initial responders? 		
Tooling 	Were the engineering tools that were to be used during the incident, available and in service? 		
Tooling 	Were the steps taken to mitigate guided by an existing runbook? 		
Total score (count of all “yes” answers above)	Total score (count of all “yes” answers above)