Cookbook Reusability

Chef Summit 2014

Transcript

1. Cookbook Reusability! Chef Community Summit 2014
2. Sean OMeara! someara@getchef.com! @someara
3. whoami
4. A Year in Review
5. Diversification
6. 7zip! apache2! ark! application*! couchdb! Imagemagick! java
7. logrotate! mercurial! munin! nagios! nginx! ntp! openvpn
8. pacman! postgresql! python! reprepro! rabbitmq! runit! supervisor
9. selinux! tmux! varnish ! wordpress!
10. Supermarket https://www.flickr.com/photos/mobilestreetlife/10885044043
11. • Escaped the tyranny of JIRA! • Moved to Github Issues! • Automated CLA checking! • OSS Artifact Repository
12. Rewrites
13. 2009 0.5.2 Chef Vagrant ChefSpec 0.1.0 0.0.2 Minitest-Chef Berkshelf Test Kitchen 2010 0.9.0 2011 0.10.0 2012 10.12.0 1.0.0 0.2.0 1.0.0 0.7.0 1.0.0 2013 2014 1.0.0 2.0.0 1.0.0 2.0.0 1.4.0 11.0.0 12.0.0 1.6.5 3.0.0 3.0.0 1.2.2 ServerSpec ChefDK 0.0.1 2.0.0 0.2.2 TDI Capability 0.8.0
14. yum! yum-*! jenkins! mysql! httpd
15. The Evolution of a Chef Cookbook
16. Stage 1 - Paradise https://www.flickr.com/photos/nattu/1385100375/
18. test / repair test / repair test / repair
19. Easy to read Easy to grok Easy to test }
20. Stage 2 - if statements
21. logic compiled into resource collection
22. Resource DSL } Just Ruby }
23. Resource DSL } Just Ruby } }Chef
24. Stage 3 - Crazytown https://www.flickr.com/photos/kwl/4595324641
26. wat
27. Why?
28. Reusable is useful
29. Cross-platform is useful
30. We desire useful things
31. Platform idioms are hard
32. Keeping the Dream Alive https://www.flickr.com/photos/kalexanderson/7014655351/
33. Most people just write their own cookbooks from scratch
34. I really really really want reusable cross-platform cookbooks
35. Lessons Learned
36. Attributes are routinely abused https://www.flickr.com/photos/jabberwocky381/2828863789
38. Attributes are an interface
39. Attributes are tunable knobs
41. You probably just want a variable
43. Or even a method
45. Using an attribute to track state during a Chef run causes tears and sorrow
46. Prefer resource parameters
49. Primitives are more useful than opinionated policy
50. “They’re Just Resources”! ! LWRP is Googleable
51. Zoom out a level! ! Think about services and runtimes, not files and processes
52. Singleton resources are good but confusing. Possibly even dangerous.! ! Multiple instance support is better! ! Cross-platform resources are best
54. BDD / TDD yields high quality cookbooks https://www.flickr.com/photos/glenirah/4376553184
55. Test Kitchen! ServerSpec / Minitest / Bats! ChefSpec
56. 2009 0.5.2 Chef Vagrant ChefSpec 0.1.0 0.0.2 Minitest-Chef Berkshelf Test Kitchen 2010 0.9.0 2011 0.10.0 2012 10.12.0 1.0.0 0.2.0 1.0.0 0.7.0 1.0.0 2013 2014 1.0.0 2.0.0 1.0.0 2.0.0 1.4.0 11.0.0 12.0.0 1.6.5 3.0.0 3.0.0 1.2.2 ServerSpec ChefDK 0.0.1 2.0.0 0.2.2 This Slide Again 0.8.0
57. Full test coverage is tedious
58. Full test coverage is totally worth it
59. Let users bring their own configurations
60. It is better to add to a resource_collection than to monkey patch it
61. Configuration files are the brains of a service
62. Manage minimal configuration to get a service running
63. Offload further configuration to the user
64. conf.d is your friend
65. Hide everything else inside a resource
66. Add resource parameters when appropriate
69. Cross-platform cookbooks are hard https://www.flickr.com/photos/glenirah/4376553184
70. Cross-platform resources are even harder
71. They can be done!
72. Create a resource
74. Create a provider
76. Subclass platform providers
82. Set provider default for platforms
84. Do Repeat Yourself
85. Some resources are often the duplicated across providers
86. That’s fine. It’s the pattern as a whole that’s important
87. Maximize for grokability
88. People will be reading your code for the first time during operations work
89. Init systems are annoying
90. Using a service resource usually requires file or template resources in addition to service[thingd]
91. Debconf! Docker! LaunchD! Runit! SMF! Simple! SystemD! Sysvinit! Upstart! Windows Services
92. Subclassing is awesome
94. Customize before recipe compilation
95. Going Forward
96. Cookbooks that ship resource primitives
97. More examples to copy
98. More breaking backwards compatibility (sorry)
99. Providers implemented with Docker containers (why not?)
100. chef-metal
101. Tell me what you think
102. Please don’t hurt me =)