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Gitaly performance problems on some servers

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Summary

Gitaly performance problems on some servers leading to growing sidekiq queues.

Root Cause Analysis issue: https://gitlab.com/gitlab-com/gl-infra/infrastructure/issues/7479

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Service(s) affected : ~"Service:Gitaly" ~"Service:Sidekiq"

Team attribution :

Minutes downtime or degradation :

Timeline

2019-08-08

  • 00:30 UTC - CPU usage on file-33,34,35 starts going up (customer started importing repos with many tags)
  • 01:47 UTC - cache_vulnerability_history feature flag enabled
  • 04:24 UTC - gitaly latency APDEX starts going down, CPU usage on file-33,34,35 reaches 80%
  • 05:10 UTC - web_hook queue starts growing
  • 05:29 UTC - gitaly latency APDEX alert in #alerts-general
  • 06:28 UTC - Incident opened by EOC
  • 06:31 UTC - #backend and #g_gitaly pinged for support
  • 06:41 UTC - IMOC pinged via /pd-mgr
  • 07:21 UTC - status.io post
  • 08:03 UTC - users librideploy and dann30 blocked by abuse team - but it didn't help
  • 08:10 UTC - cache_vulnerability_history feature flag disabled
  • 08:16 UTC - gitaly on file-33 restarted, post receive queue starting to go down a bit, but then rises again
  • 08:25 UTC - gitaly on file-34 restarted
  • 08:29 UTC - gitaly on file-35 restarted
  • 08:50 UTC - collecting profiling data from gitaly on file-33
  • 09:30 UTC - profiling data reveals Gitaly spending a lot of time in FindAllTags
  • 11:08 UTC - starting to deploy hot patch for Gitaly n+1 calls to prod
  • 11:14 UTC - post_receive queue starting to decline
  • 11:20 UTC - deployment of hot patch finished
  • 11:45 UTC - problematic jobs manually killed
  • 13:00 UTC - reports of MRs being closed inadvertently (#1040 (closed))
  • 13:16 UTC - hot patch reverted as it wasn't clear if it's causing the closed MRs
  • 14:30 UTC - manually added web_hook to queue groups on the pages sidekiq nodes to accelerate queue processing
  • 14:55 UTC - queues down to zero
Edited by Henri Philipps