What is true about class declarations in Puppet?

In Puppet, classes are designed to be singleton objects. This means that each class can only be declared once within a manifest or module. When a class is declared, its content is evaluated and applied, but if that same class is declared again, Puppet recognizes that it has already been declared and skips re-evaluating it. This is a critical aspect of how classes function in Puppet, as it ensures that resources managed by the class are not duplicated, which could lead to conflicting configurations or unintended behavior.

The singleton nature of classes simplifies resource management and configuration, as it prevents multiple instances of the same configuration from being applied. This allows a more predictable and stable infrastructure when using Puppet, as it ensures that the same configuration is applied consistently.

While there are other options regarding multiple declarations, the key concept to focus on is that classes themselves are inherently designed to be declared only once, making them unique within a Puppet environment.