In Puppet, which file extension is commonly used for class definition files?

The commonly used file extension for class definition files in Puppet is .pp. This extension signifies that the file contains Puppet code, specifically written in Puppet's domain-specific language (DSL). Class definition files are fundamental to Puppet as they encapsulate the configuration logic and can be included and managed within Puppet manifests.

By convention, Puppet files with the .pp extension typically contain resource declarations, class definitions, and module configurations that define how systems should be configured. The use of this extension helps both Puppet and users clearly identify the purpose of the files, making it easier to maintain and organize Puppet code.

In contrast, other extensions like .json and .yaml are used for data serialization formats, which are not standard for class definitions in Puppet. .rb is associated with Ruby scripts, which can be used in conjunction with Puppet for certain extensions and functions but is not the primary format for defining Puppet classes.