Puppet concat patterns
It’s common to want to configure a shared resource from many classes in your module tree, each class defining it’s own configuration parameters that then merge into a more unified whole.
When the resource you’re configuring natively supports a conf.d style this makes the configuration management job quite simple, you just drop out a new file from each class that’s interested and call it done.
The complexity comes when you have a single file that you need to manage.