Which parameter of the exec resource allows execution only if a specific condition is true?

The onlyif parameter of the exec resource is essential when you want to execute a command only if a specific condition is true. This parameter allows you to define a command that must succeed for the exec resource to run the main command specified in the exec resource.

When using the onlyif parameter, Puppet evaluates the command provided as its value before executing the main command. If the onlyif command returns a zero exit status, indicating success, then the main command is executed. This is particularly useful for scenarios where you want to ensure that a task is performed only under certain conditions, such as checking if a file exists or if a service is running before proceeding with further actions.

In contrast, the creates parameter is used to define a file that, if it exists, will prevent the exec resource from running, while the unless parameter is the opposite of onlyif; it specifies a command that, if successful, will cause the main command not to run. The refresh parameter is related to triggering execution of the command based on changes in a different resource, not conditioned execution based on command success.

Thus, the decision to use the onlyif parameter effectively ensures that the commands specified within an exec resource are executed only when the desired prerequisite condition holds true, leading to more predictable