Love/Hate Puppet Melbourne

This is the talk i gave at PuppetCamp Melbourne on the 08/02/2013

Transcript

1. Love / Hate Puppet Stephen Johnson Stephen@puppetlabs.com Wednesday, 20 March 13
2. Background • Puppetlabs employ for a a year • I have been using Puppet since 0.24 • Currently working on the hiera_debug and rseencfile projects Wednesday, 20 March 13
3. What is this • Its not a puppet bashing • Interesting Puppet behavior • What i love about puppet Wednesday, 20 March 13
4. Interesting Behavior • Type Casting • Type Equality • Inconsistencies • Scoping Wednesday, 20 March 13
5. Type Casting (FTW) • $wibble = “3” (String) • $wibble2 = “2” (String) • $wtf = $wibble + $wibble2 ? Wednesday, 20 March 13
6. Int Wednesday, 20 March 13
7. Type Equality • $wibble = '3' • $wibble2 = '2' • $wibble3 = $wibble + $wibble2 • $wibbletest = 5 • is $wibble3 == $wibbletest Wednesday, 20 March 13
8. Yes Wednesday, 20 March 13
9. Type Equality 2 • $wibble = ‘true’ • $wibble2 = true • is $wibble == $wibble2 Wednesday, 20 March 13
10. No Wednesday, 20 March 13
11. Type Equality 3 • $wibble = 0 • $wibble2 = -1 • are they equal to true Wednesday, 20 March 13
12. Yes Wednesday, 20 March 13
13. Totally Confused Now Wednesday, 20 March 13
14. Wednesday, 20 March 13
15. Type Equality • There are many many more • Be careful with data lookups from hiera Wednesday, 20 March 13
16. Inconsistencies • Noop on a class Wednesday, 20 March 13
17. Noop on class • class{'testtwo': noop => true ;} • All the resources are noop surely Wednesday, 20 March 13
18. The code Wednesday, 20 March 13
19. The output Wednesday, 20 March 13
20. Wednesday, 20 March 13
21. Scoping • Thank god for 3.0 • Removing dynamic scoping Wednesday, 20 March 13
22. 2.7 • Dynamic scoping is very very very dangerous • Always use full scoped values Wednesday, 20 March 13
23. 3.0 • It has been removed • Full scope variables Wednesday, 20 March 13
24. Facts • Top level variables • Do not trust them as sent from client • Dont use if $::hostname == • Export FACTER_hostname=‘puppetmaster’ • puppet agent -t • See my blog on thatbytes.co.uk Wednesday, 20 March 13
25. Is not all bad • All languages have interesting behavior • Look at the famous “WAT’ talk from Gary Bernhardt • www.destroyallsoftware.com/talks/wat Wednesday, 20 March 13
26. What i love • Exported Resources • Puppet • Hiera Wednesday, 20 March 13
27. Exported Resources • Nagios is so hard to setup all those config files • Dns is so hard we have to track all those ip address Wednesday, 20 March 13
28. Nagios Automated • Nagios node  webserver  {        @@file  {  "/etc/nagios/conf.d/$::fqdn.apachecheck.conf":              content  =>  "nagios  check  stuff  \n",              tag  =>  "nagioscheck",                    }              }            node  nagiosmachine  {                File  <<|  tag  ==  'nagioscheck'  |>>            } Wednesday, 20 March 13
29. Export the resource • @@file  {  "/etc/nagios/conf.d/$::fqdn.apachecheck.conf":              content  =>  template(‘apache/nagioscheck.erb’),              tag  =>  "nagioscheck",                    } • Tagged with nagioscheck • Have a apache::nagios class ? Wednesday, 20 March 13
30. Collect the resource File  <<|  tag  ==  'nagioscheck'  |>> • Using the tag previously • In your nagios::server class Wednesday, 20 March 13
31. How does that work • Puppetdb • Stores configs • Scalable • AWESOMENESS Wednesday, 20 March 13
32. Puppet • Automation • Abstraction • Repeatable • Reportable • AWESOMEABLE Wednesday, 20 March 13
33. Puppet gets you Knowledge • Version controlled infrastructure • Convergence • Reporting • Query-ability • Removing the snowflakes Wednesday, 20 March 13
34. Hiera • Puppet modules without hard-coded data are easily shared and more re-usable • Infrastructure configuration can be managed without needing to edit Puppet code • The data problem Wednesday, 20 March 13
35. Bad Data if ( $::environment == ‘dev’ ) { $ntpserver = ‘192.168.2.1’ } else { if ( $::fqdn == ‘host4.mycorp.com’) { $ntpserver = ‘127.0.0.1’ } else { $ntpserver = ‘213.21.6.4’ } } Wednesday, 20 March 13
36. Good Data $ntpserver = hiera(‘ntpserver’) :hierarchy: - %{operatingsystem} - %{environment} - %{fqdn} - common Wednesday, 20 March 13
37. Remove Data from Code • Hiera uses information to determine a hierarchy • Top down hierarchy for overriding configuration values based on roles, environments, locations.... or anything else • And do this without any coding! Wednesday, 20 March 13
38. Puppet 3.0 • Hiera is integrated into the core product • Introduces data mapping for parameterized classes • Backwards compatible Wednesday, 20 March 13
39. Hiera_Debug Wednesday, 20 March 13
40. Hiera • What where the variables • How looked the variables up Wednesday, 20 March 13
41. Debug File Wednesday, 20 March 13
42. Learn more • git://github.com/nfagerlund/evil-made- manifest.git Wednesday, 20 March 13