This is a support agent for the HTTP generator that allows modification to a subset of the Apache configuration variables in the experiment
Provides interface for starting and stopping a shared instance of the Apache server
Set a configuration value k to value v in the apache.conf file, doesn’t take effect until the next time apache is actually stopped and started
Request that the apache server be started for this agent group. If apache is already running, it simply increments the usage counter.
Notify the apache server that this agent group no longer needs it. If this is the last group using it on this node, stop the apache server.