chef talk at DevOps Singapore

Meetup: http://www.meetup.com/devops-singapore/events/180863352/

1. chef May 15 2014
 Claudio Mettler, CtrlM Singapore Pte. Ltd. 1
2. ME ME ME ME • In Singapore since mid-2013 • CtrlM • Focusing on: ruby/rails, objC, JS and PHP • info@ctrlm.ch 2
3. use cases • distributed development environments (with vagrant) • large server infrastructure, physical or IaaS • Phoenix Servers: http://martinfowler.com/bliki/ PhoenixServer.html and http://martinfowler.com/ bliki/SnowflakeServer.html 3
5. chef in general • ist mostly ruby • makes use of domain specific languages • partly open source (apache license) • in active development 5
6. chef server • stores cookbooks, roles, node data • can be queried • hosted: enterprise chef • self-hosted: enterprise chef, open source chef (64 bit only) • differences: ACL, organizations, LDAP, nicer UI and obviously less hassle 6
7. enterprise chef pricing 7
8. chef client • runs on instance to be provisioned (called a node) • communicates with server • self-registers node • has a run list • gets cookbooks and other configuration information • idempotently brings node into desired state 8
9. chef-client: how does it get there? • knife bootstrap • knife ec2, knife do etc. • manual installation/deliver with image • new: chef metal 9
10. ohai • part of chef-client • finds out useful things about the node it runs on • information will then be stored in the node object 10
11. chef workstation • used for: • authoring cookbooks • managing cookbooks, roles, databags etc. • bootstrapping nodes (ssh) • uploading cookbooks etc. to server • main tool: knife • state kept in scm (most likely git) 11
12. cookbooks • collection of recipes, attributes and metadata (and other stuff) • can have dependencies • usually has a “default” recipe • community cookbooks and home made cookbooks • examples: apache2, mysql, mywebapp 12
13. community cookbooks vs. DIY • community cookbooks try to run everywhere • try running apache cookbook on ubuntu 14.04 though… • lots of platform specific code • lots of configurability • decide on a case-by-case basis • do NOT automatically update 13
14. run lists • collection of roles, cookbooks, recipes • expands to a list of recipes and attributes 14
15. roles • attributes + a run list • expands to attributes + a list of recipes 15
16. chef-solo • server-less chef client mode • does not store node data • use case: simple (one-server) projects, development environments, testing, deploying chef-server 16
17. chef-zero • in-memory chef server • does not do authentication • mainly for development and testing 17
18. one more thing: berkshelf • downloads cookbooks • resolves dependencies • uploads to server • manages cookbooks locally • part of chef development kit (chef-dk) 18
19. let’s try something 19
20. cloud services • knife ec2 server create -r "role[webserver]" -I ami-2d4aa444 --flavor m1.small -G www,default - x ubuntu -N server01 • knife digital_ocean droplet create --server-name awesome-vm2.chef.io --image 25306 --location 4 --size 66 --ssh-keys 1234,1235 --bootstrap --run- list "role[base],role[webserver]" 20
22. cookbooks are not just recipe collections • definitions • Lightweight Resource/Provider • attributes 22
23. resources • “A resource defines the desired state for a single configuration item present on a node that is under management by Chef.”
 (http://docs.opscode.com/resource.html) • Examples: system user, folders, files, packages, execute, deploy • has: attributes, actions, guards, guard interpreters 23
24. providers • the code behind a resource • can depend on the OS (etc.) on the node • example: “package” resource may use: apt/ dpkg, rpm, gem etc. • sometimes you still need to handle different OS/ distributions (example: apache package) 24
25. LWRP • lightweight resource/provider • a more declarative/DSL way to create resources/ providers • can be supplied by cookbooks 25
26. definitions • almost resource/provider • no de-coupling • often contains resources • discouraged 26
27. attributes • in the end make up the node object • sources: ohai, attribute files, recipes, environments, roles • types: default, force_default, normal, override, force_override, automatic • become one big json-style tree 27
28. attribute precedence • A default attribute located in a cookbook attribute file • A default attribute located in a recipe • A default attribute located in an environment • A default attribute located in role • A force_default attribute located in a cookbook attribute file • A force_default attribute located in a recipe • A normal attribute located in a cookbook attribute file • A normal attribute located in a recipe • An override attribute located in a cookbook attribute file • An override attribute located in a recipe • An override attribute located in a role • An override attribute located in an environment • A force_override attribute located in a cookbook attribute file • A force_override attribute located in a recipe • An automatic attribute identified by Ohai at the start of the chef-client run 28
29. attribute precedence, simplified • default, force_default, normal, override, force_override, automatic • cookbook, recipe, role, environment • automatic comes from ohai only 29
30. my little cookbook • deploy a static website • use the webapp definition from the apache cookbook • configurable via attribute 30
31. let’s do it 31
32. let’s iterate • we want 2 different sites. or maybe 3? • maybe we should have a dev environment? 32
33. data bags • have a name • contain named items • items are JSON style data • globally available • can be encrypted 33
34. environments • default environment is called _default • _default can’t really be modified • other environments can contain attributes and cookbook version constraints 34
35. on with it 35
36. foodcritic • lint tool for cookbooks • part of chef-dk 36
37. let’s have a look 37
38. chef metal • very new (version 0.10.2) • machine resource • abstracts cloud, VMs, Containers etc. • allows you to put a cluster configuration into a file 38
39. what else? • testing: • test-kitchen for integration testing across various platforms (using vagrant, usually) • ChefSpec: RSpec based unit testing • both are part of chef-dk • querying the server 39
40. http://learnchef.opscode.com/
 HTTP://docs.opscode.com/ 40
41. ? 41
42. ! 42