How to generate good serials for DNS zones with Puppet?
Don't use a template, if you try to use a serial number there the problem is your going to keep making changes each time.
I have two ideas:
- Create a proper type that can manage DNS using DNS updates via the standard API. Then let BIND do the serial number increments itself.
- Use a file fragment pattern on each element within your DNS zone, and have it so that the main zone file only gets updated when these change. You do this by having a 'zone refresh' exec that concats your parts into the final zone including the header. The difference between most file fragment solutions would be that you generate your zone serial from a timestamp or some such, which should only ever get triggered when the parts are changed thus avoiding the constant serial number changes you would get from a template.
Some examples of the file fragment pattern are here:
http://projects.puppetlabs.com/projects/puppet/wiki/Generating_a_config_file_from_fragments
https://github.com/ripienaar/puppet-concat
How about using the timestamp of the file:
file { "/tmp/dafile": content = inline_template("<%= File.mtime("/tmp/dafile").to_i %>"), }
The only thing is that this will probably run on each client and may update the timestamp of the file for every run. If it doesn't, it should suit your requirement.