At Etsy we run our production stack exclusively on physical hardware and have (including developer and CI VMs) about 1000 nodes managed with a single Chef server running the same cookbooks across development and production nodes. We have built the knife-spork plugin to support our workflow and have 30 engineers making changes about 20 times a day. While this setup keeps configuration changes and package installations consistent across our network, it makes it harder to gradually roll out and test changes on a per node or role basis. In the talk our general workflow will be introduced and explained and how we enable engineers to frequently roll out small changes. Following the general introduction, our workflow for testing changes will be discussed and the library we wrote to enable config flags and gradual roll outs for our infrastructure within our chef recipes.

1. Feature Flagging your
Infrastructure for Fun and
Pro!t
Daniel Schauenberg
dschauenberg@etsy.com
@mrtazz
Tuesday, September 10, 13

2. Tuesday, September 10, 13

3. LAMMP
Item by TheBackPackShoppe
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4. Item by FrankelPhotos
Monolithic App
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5. Etsy Infrastructure
•~1400 nodes
•~30 dev & ops engineers making changes
regularly
•Open Source Chef server + GitHub Enterprise
•Default environment setup (production,
development, testing)
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6. jonlives/knife-spork
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7. knife-spork
•Work!ow to manage cookbook and environment
changes
•Versioned cookbooks and pinned environments
•Speci"c work!ow, di#erent ways of using plugins
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8. Tuesday, September 10, 13

9. % chef-shell
chef > recipe_mode
chef:recipe > echo off
chef:recipe > include_recipe "apache"
chef:recipe > run_chef
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10. % review -r jcowie --cc ops
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11. % knife spork check apache
% knife spork bump apache
% git commit
% git push
% knife spork upload apache
Staging Deploy
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12. jonlives/knife-!ip
% knife node flip node.etsy.com testing
% knife role flip testRole testing
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13. % knife spork promote apache
% git commit
% git push
% knife spork promote apache --remote
Production Deploy
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14. Monitoring
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15. 19:18:06 irccat | CHEF: Daniel
Schauenberg promoted apache@0.0.2 to
development https://
github.etsycorp.com/gist/12345
Tuesday, September 10, 13

16. etsy/chef-handlers
19:20:00 irccat | Chef run failed on test.etsy.com
19:20:00 irccat | https://github.etsycorp.com/
gist/12347
jgoulah/knife-lastrun
% knife node lastrun test.etsy.com
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17. Graphs!
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18. Downsides
•Longer testing blocks others
•Staged cookbooks can accidentally be promoted
•Testing environment a#ects more than one
cookbook
•Used “upgrade” environments to circumvent
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19. Feature Flags
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20. Branching in Code
•Well established pattern for “dark launches”
•Used in the Etsy Web stack
•Allows for restricted roll outs
•http://code.!ickr.net/2009/12/02/!ipping-out/
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21. Tuesday, September 10, 13

22. etsy/chef-whitelist
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23. chef-whitelist
•Data bag driven whitelist
•Library to include in cookbooks
•Easy access to feature !ags
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24. whitelist data bag
{
"id": "my_whitelist",
"patterns": [
"host.example.com",
"*.subdomain.example.com",
"prefix*.example.com"
]
}
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25. whitelist data bag{
"id": "my_whitelist",
"patterns": [
"host.example.com",
"*.subdomain.example.com",
"prefix*.example.com"
],
"roles": [
"Webserver",
"DatabaseServer"
]
}
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26. feature !ags in recipe
if node.is_in_whitelist? "my_whitelist"
# new hawtness
else
# old stuff
end
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27. Customizable
node.is_in_whitelist? "my_whitelist", "acl", "hosts"
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28. real world
example
{
"id": "php-5-4-19",
"patterns": [
"dschauenberg.vm.dev.etsy.com",
"web0270.etsy.com",
"api04.etsy.com",
"imgcache01.etsy.com",
"imgwriter01.etsy.com",
"worker01.etsy.com",
"beacon01.etsy.com",
"paymentsweb01.etsy.com"
],
"roles": [
]
}
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29. Advantages
•Easy to access list of what gets upgrades
•Upgrades don’t need the spork work!ow
•Pattern already known by all engineers
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30. Downsides
•Changes outside the regular work!ow
•No graphs (yet)
•Less visible cleanup required
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31. Summary
•GitHub Enterprise, Dev VMs, chef-shell as
development environment
•Chef Server and knife-spork as Deployment
System
•Feature !agging with chef-whitelist
•Monitoring, Noti"cations, Graphs
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32. •http://codeascraft.etsy.com/
•http://codeascraft.com/2013/08/02/
infrastructure-upgrades-with-chef/
•http://www.slideshare.net/jonlives/michelin-
starred-cooking-with-chef
•http://www.slideshare.net/mcdonnps/lessons-
from-etsy-avoiding-kitchen-nightmares-
chefconf-2012
•https://github.com/etsy
Further information
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33. Thank you!
Questions?
Tuesday, September 10, 13

34. Feature Flagging your
Infrastructure for Fun and
Pro!t
Daniel Schauenberg
dschauenberg@etsy.com
@mrtazz
Tuesday, September 10, 13