Puppet can resolve variable in a lot of ways. Here we describe the approach we use for managing the Elexis-admin project.
Its component are
- Hiera allows a hierarchical search to get variables from. The search strategy is defined in the file
- hiera.yaml. It uses YAML and GPG (to encrypt passwords) as dackends to store the content
- it defines also the root folder where it searches for files. We use the default /etc/puppet
- The hierarchy is quite small, but allows you to get your variables (search ends at first match)
- in a host specific yaml file (you may specify one with “hostname=myHostToTest”
- in environment specific yaml file. The environment can be specified when calling puppet or hiera adding “env=test”
- in private/config.yaml. This allows you to override most setting
- in hiera/common.yaml. There you find a commented -but not actived – list of all settings
- puppet classes can have default values. It is good practice to define possibly varying thins as class variables
(e.g. specific version of a package, a path to database).- Some generally useful values can be found under modules/elexis/init.pp
- Use puppetforge modules whereever possible.
Most features of the Elexis-Admin are opt-in/opt-out. E.g if you have in your private/config.yaml a line x2go::client:ensure: absent no x2go-client will be installed. If there was installed before, it will be removed.