Which provisioner runs a process on the created resource?

The provisioner that runs a process on the created resource is the remote-exec provisioner. This type of provisioner is designed to execute scripts or commands directly on the remote resource that has just been created. For example, if you are provisioning a virtual machine in the cloud, the remote-exec provisioner allows you to run commands within the context of that machine after it has been provisioned.

Using the remote-exec provisioner is beneficial when you need to configure the resource or install software as part of the deployment process. It connects to the resource via SSH (for Linux-based systems) or WinRM (for Windows), executing the specified commands in the proper environment of the created resource.

In contrast, the local-exec provisioner runs commands on the machine where Terraform is executed, not on the target resource itself. Null-exec is a placeholder provisioner that does nothing, and "command-exec" is not a recognized Terraform provisioner type. Thus, remote-exec is the correct choice for running processes on the resource that has been created.