1. Configuration Manager
Puppet, Chef, Cfengine
Presented by
Jérémy MATHEVET

2. Topics
1. Principle
2. Comparison
3. Puppet
4. Chef
5. Cfengine
6. Migration advises

3. Principle

4. Principle
• A client/server architecture.
• The server has a reference configuration.
• The client queries the server.
• The client makes change in order to match
the reference configuration.

5. Principle
1. “Can you give my configuration model ?“
2. “Ok, for you, that's it.”
3. “I make the necessary in order to fulfil it.”
4. (optional) “Thank you, I'm ok, no error” or
“I had a problem”.

6. Principle

7. Why to do this ?
• Centralized management
• Automated management
• Mass deployment
• Configuration customization
• Abstraction Layer
• Idempotence

8. What can we do ?
• File transfer
• Service management
• Package management
• Command launching

9. Comparison

10. Comparison
3 major solution :
• Puppet
• Chef
• Cfengine
Pretty similar possibilities.
Some specificities.

11. Comparison
Puppet Chef Cfengine
Pull Yes Yes Yes
Push No No No
Idempotence Yes Yes Yes
Config language Declarative Ruby Declarative
Web UI Yes (limited) Yes No
OS Support Linux/Unix – Linux/Unix –
Linux Linux/Unix –
Windows Windows Windows
(experimental) (experimental) (experimental)
Licence GPL v2 Apache GPL
Company Puppet Labs OpsCode Cfengine
Cloud Yes SaaS platform Yes

12. Puppet

13. Puppet
• Created in 2006 by Puppet Labs
• The easiest solution
• Proprietary declarative language
• Modular configuration
• Template
• Asymmetric Key Encryption

14. Puppet
• Prerequisite :
• Configured DNS
• Ruby
• Installation Sources :
• Debian Repositories
• RubyGem
• Sources

15. Puppet
• Puppet server : Puppetmaster
• Puppet client : Puppet (agent)
Main steps once installed :
• Key exchange
• Puppetmaster configuration
• Puppet agent checks every 30 mn by default

16. Puppet
Vocabulary :
• Node
• Manifest
• Module
• Class
• Template

17. Puppet

18. Puppet
Here is the read order.
• site.pp : global config
• nodes.pp : manage
hosts
• init.pp : module classes
• Files : module files
directory

19. Puppet

20. Puppet
• Facter : Give node facts.
• Permit to have
customized
configuration node.
• Possibility to create
your own facts.

21. Puppet
Templates
• ERB
• Customize configuration using Facts
Exemple :

22. Puppet
Puppet Dashboard
• WebUI
• Still in development
• Very buggy
• Only for monitoring
• Useless for the moment

24. Chef

25. Chef
• Created in 2009 by Opscode
• Sustained development
• Configuration language : Ruby
• Modular configuration
• Template
• Asymmetric Key Encryption

26. Chef
• Prerequisite :
• Configured DNS
• Ruby
• Installation Sources :
• Opscode Repositories
• RubyGem
• Sources

27. Chef
• Chef server : chef-server
• Chef client : chef-client
Main steps once installed :
• Key exchange
• Chef-server configuration
• Chef client checks every 30 mn by default

28. Chef
Vocabulary :
• Recipes
• Cookbook
• Role
• Node
• Attributes
• Knife
• Chef Repository

29. Chef

30. Chef
Chef Server is in fact several processes.
•API Service
Used to interact with server for node configuration.
•Management Console
WebUI which permits to do administrative tasks.

31. Chef
• File indexer
Apache SOLR, a search engine.
• Data store (CouchDB)
Used for store roles, nodes and data bag JSON data. Sends
it to SOLR, through AQMP queue.
•AQMP Server
Used by CouchDB as queue.

32. Chef

33. Chef
Cookbook

34. Chef
Recipes

35. Chef
Recipes
Like in Cooking, one of the more interesting
thing is to share our cookbooks and recipes.
http://community.opscode.com/cookbooks

36. Chef
Ohai and templates
A tree of node facts, which can be used as
attributes.
The same kind of customization as Puppet
with Facter.

37. Chef
Administration
•Knife or Management Console
•CLI or Web UI
•Two powerful tools

39. Chef vs Puppet
Chef Advantages
• Cookbooks sharing
• Stricter configuration rules
• Ruby
• Useful WebUI
Disadvantages
• A bit more complex
• More setup needed
• Usable in production, but still young

40. Cfengine

41. Cfengine
• Created in 1993 by Mark Burgess
• The first configuration manager
• Major update in 2009, Cfengine 3
• Proprietary configuration language
• Template
• Asymmetric Key Encryption

42. Cfengine
• Prerequisite :
• libc
• Installation Sources :
• Debian Repositories
• Sources

43. Cfengine
Cfengine has an
atypical
mechanism.
There is neither
cfengine-server nor
cfengine-client
package.

44. Cfengine
Architecture

45. Cfengine
Vocabulary
• Promises
• Body & bundle
• Class

46. Cfengine
Promises

47. Cfengine
•Bundles and bodies

48. Cfengine
•With Cfengine, you have to do configure
everything. From the promises, to the host
authorized, or the failsafe procedure.

49. Cfengine vs Puppet vs Chef
Cfengine is powerful. But...
• Painful configuration
• Have fun with log (excessively verbose... Or not.)
• Seems outdated compared to Puppet and Chef
Keep in mind that you have as much
possibilities as Puppet & Chef. But the time
you pass configuring and master it is
incomparable.

50. Migration advices

51. Migration advices
• Migration have to be progressive.
• Writing configurations take time.
• Be extremely rigorous.
• Don't forget the revision control.

52. Questions?
Contact:
Email : jeremy.mathevet@supinfo.com
StatusNet : jeyg@status.jeyg.info
Twitter : @Jeyg
Content under Creative Commons BY license.