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