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Incidents/2022-03-06 wdqs-categories

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document status: in-review

Summary

Incident metadata (see Incident Scorecard)
Incident ID 2022-03-06 wdqs-categories Start 2022-03-06 13:50
Task End 2022-03-06 17:24
People paged sre Responder count 3
Coordinators 0 Affected metrics/SLOs
Impact For 1.5 hour, some requests to the public Wikidata Query Service API were sporadically blocked.

The service got overloaded and started to block client traffic, including Pybal which ultimately triggered the page.  Icinga sent some non-paging alerts at 13:50 but paging alerts didn't get sent until 16:52.

Timeline

  • 13:50 Icinga alerts about CRITICAL - CRITICAL - wdqs-heavy-queries_8888 - none paging
  • 16:52 Icinga notifies about Wikidata Query Service wdqs eqiad - outage starts, paging
  • 16:57 Icinga notifies about Wikidata Query Service wdqs eqiad - paging
  • 17:02 Icinga notifies about Wikidata Query Service wdqs eqiad - paging
  • 17:05 joe restarts wdqs1006
  • 17:07 Icinga notifies about Wikidata Query Service wdqs eqiad - paging
  • 17:07 load on wdqs1006 increases to 120
  • 17:15 jbond tries to reach search team, contacted gehel
  • 17:17 gehel comes online
  • 17:21 jbond restart wdqs services (at gehels request) clusterwide (wdqs::public)
  • 17:24 RECOVERY messages in -operations - outage ends

Documentation:

02:15:05.481 [qtp2137211482-702147] INFO  o.w.q.r.b.t.ThrottlingFilter - A request is being banned. req.requestURI=/bigdata/namespace/wdq/sparql, req.xForwardedFor=10.64.1.19, req.queryString=query=%20ASK%7B%20%3Fx%20%3Fy%20%3Fz%20%7D, req.method=GET, req.remoteHost=localhost, req.requestURL=http://localhost/bigdata/namespace/wdq/sparql, req.userAgent=Twisted PageGetter
  • Fix required restarting the wdqs services on the cluster
    sudo cumin -b 1 -s 1 O:wdqs::public 'systemctl restart wdqs-blazegraph wdqs-categories wdqs-updater'
    

Actionables

Scorecard

Incident Engagement™ ScoreCard
Question Score Notes
People Were the people responding to this incident sufficiently different than the previous five incidents? (score 1 for yes, 0 for no) 1
Were the people who responded prepared enough to respond effectively (score 1 for yes, 0 for no) 1
Were more than 5 people paged? (score 0 for yes, 1 for no) 0
Were pages routed to the correct sub-team(s)? (score 1 for yes, 0 for no) 0
Were pages routed to online (business hours) engineers? (score 1 for yes,  0 if people were paged after business hours) 0 as weekend
Process Was the incident status section actively updated during the incident? (score 1 for yes, 0 for no) 0
Was the public status page updated? (score 1 for yes, 0 for no) N/A
Is there a phabricator task for the incident? (score 1 for yes, 0 for no) 1
Are the documented action items assigned?  (score 1 for yes, 0 for no) 0
Is this a repeat of an earlier incident (score 0 for yes, 1 for no) 0
Tooling Was there, before the incident occurred, open tasks that would prevent this incident / make mitigation easier if implemented? (score 0 for yes, 1 for no) ?
Were the people responding able to communicate effectively during the incident with the existing tooling? (score 1 for yes, 0 or no) 1
Did existing monitoring notify the initial responders? (score 1 for yes, 0 for no) 1
Were all engineering tools required available and in service? (score 1 for yes, 0 for no) 1
Was there a runbook for all known issues present? (score 1 for yes, 0 for no) 0
Total score 6