Start or stop service automatic?

You can use an IP-address (node, VIP, public web site) or the name of a VIP for the destination of sideband connections. However, you cannot use a pool as the destination.

However, I assume that you will want to disable/enable the service on more than one server. If that is the case you wouldn't want to use a pool since that would connect you to only one server.

What you can do in an iRule is get the list of pool members and then you can iterate through those to target each node to toggle the service on each of them.