In Puppet, what is the primary role of the 'node' declaration?

The primary role of the 'node' declaration in Puppet is to define resource collections for specific nodes. This declaration acts as a way to specify which resources, classes, and configurations should apply to a particular node (or set of nodes). The node block allows you to tailor the configuration management to the specific needs and characteristics of individual systems. By doing this, Puppet can apply unique settings or resources to each node, ensuring that the configurations align with the specific environment and requirements of that system.

When you define a node declaration, you can reference classes and define resources that should be applied only to that node, enabling a highly customized and modular approach to configuration management. This function is crucial in larger environments where resources and requirements can vary significantly from one machine to another. The ability to manage these specificities within node definitions leads to more efficient and effective system management.