A collection of task oriented solutions in Puppet

Topics

 

Select a file based on a fact

Challenge

You want to deploy a specific file based on the value of a fact.

Solution

file { "/etc/mysql/conf.d/tuning.cnf":
    ensure => "present",
    source => [
        "puppet:///modules/mysql-server/tuning.$hostname.cnf",
        "puppet:///modules/mysql-server/tuning.$domain.cnf",
        "puppet:///modules/mysql-server/tuning.cnf"
    ],
}

Explanation

Sometimes you want to have specific versions of a file for a given host, location or operating system while having a default fallback for the standard cases. By using an array of sources in a file resource, with the value of a fact as part of the on-disk file name, you can easily make your configs more granular where needed while keeping sensible defaults.

In the mysql-server module you would have file names like these:

files/
    tuning.host1.cnf
    tuning.host2.cnf
    tuning.example.org.cnf
    tuning.cnf

When using multiple sources in this way puppet will use the first file that matches a source line, and cause an error if none match, so you should nearly always have a default file.

See also

Fact specific template selection TODO