This software is for those who have used jails and want a controlled way
to manage and shut them down, etc.

It is to be installed inside a jail (NOT THE HOST SYSTEM) and will
manage the processes.  A jailer process runs inside each jail and
manages the startup and shutdown.

To shutdown or restart the jail, signal the jailer process running
inside that jail.  The signals are:

  -QUIT	Shutdown jail but leave jailer running
  -HUP	Restart the jail 
  -TERM	Shutdown the jail and exit the jailer

WWW: http://memberwebs.com/nielsen/freebsd/jails/jailer/