PHP and Console

I need to implement a PHP client and server for kill process from one server to other.
Let's say I have server A and server B.
A wants to kill a process in server B.
A ask that by web and a php create a task into a file, then in a contab script, I run a php that read every one minute posible task and then kill process if it allowed.
The contab execute php as root.

Is it clear?

Is this method safe?

I dont know if is there another more secure way to kill process through internet or a VPN. Is it other?

Thanks to all