Which type of resource would you use to ensure a service is restarted after a configuration file change?

To ensure that a service is restarted after a configuration file change, the appropriate resource type to use is the Service Declaration. This resource type is specifically designed to manage services on the system, allowing you to define how a service should be started, stopped, or restarted based on changes detected in associated resources.

When a configuration file (often managed by a File Resource) is altered, a Service Declaration can be utilized in conjunction with notifications. By leveraging the notify or subscribe attributes in Puppet, you can instruct the Service Declaration to restart the associated service whenever the configuration file is updated. This ensures that any changes in the configuration are applied and the service runs with the new settings, maintaining the desired state of the application or service.

In summary, using a Service Declaration allows Puppet to manage the lifecycle of services and ensures they are appropriately restarted following changes to their configuration files, thereby maintaining system reliability and performance.