What will happen if a node is included in more than one role?

When a node is included in more than one role, the most recently declared role takes precedence. In Puppet, roles are a way to encapsulate configurations so that multiple nodes can share common settings. When a node is associated with multiple roles, Puppet processes them in the order they are defined within the manifests and applies the last one encountered.

This behavior allows for flexibility in managing node configurations. For instance, if a node inherits configurations from several roles, it can be overridden by a subsequent role definition, ensuring that the most relevant or needed configurations are applied effectively. Puppet's catalog compilation process is designed to evaluate multiple roles, applying the last one as the definitive source of configuration for the node.

Regarding the other possible outcomes: if compilation were to fail, it would indicate syntax errors or conflicts that aren't typically caused merely by multiple role declarations. If all roles were to apply without regard for the declared order, it could lead to conflicting configurations being applied, which would not be manageable. The concept of a default role implies there is a predefined role to use if none is specified, but in this context where multiple roles exist, the last declared becomes the working configuration. Thus, the priority of declaration ensures a clear resolution path in dynamically managing node configurations.