In puppet manifests, what does the 'contain' function do?

The 'contain' function in Puppet manifests is used to include a class within the scope of another class or defined type. One of its key characteristics is that it maintains the order of execution for resources. When a class is contained within another, it ensures that all of the resources defined in the contained class are considered during compilation, and their execution happens in the order specified, respecting the dependencies and their respective relationships in subsequent resource declarations.

This function is valuable for organizing manifests, allowing developers to modularize their code. By using 'contain', you can manage dependencies effectively within classes, preventing potential issues that could arise from unordered resource execution. In contrast, simply using the 'include' function does not retain this order of execution, potentially leading to unexpected behaviors.

Understanding the implications of how and when to use 'contain' is critical for ensuring that resources are applied in the desired sequence, aligning with the overall architecture of the Puppet configurations.