The stopping event is generated by the Upstart init(8) daemon  when  an
       instance  of  a job begins stopping.  The JOB environment variable con-
       tains the job name, and the INSTANCE environment variable contains  the
       instance name which will be empty for single-instance jobs.

       If  the  job is stopping normally, the RESULT environment variable will
       be ok, otherwise if the job is stopping because it has failed  it  will
       be failed.

       When  the  job has failed, the process that failed will be given in the
       PROCESS environment variable.  This may be pre-start, post-start, main,
       pre-stop  or  post-stop;  it  may  also be the special value respawn to
       indicate that the job is stopping because it hit the respawn limit.

       Finally in the case of a failed  job,  one  of  either  EXIT_STATUS  or
       EXIT_SIGNAL  may  be  given  to indicate the cause of the stop.  Either
       EXIT_STATUS will contain the  exit  status  code  of  the  process,  or
       EXIT_SIGNAL  will  contain  the  name  of  the  signal that the process
       received.  The normal exit job configuration stanza can be used to pre-
       vent  particular  exit  status  values or signals resulting in a failed
       job, see init(5) for more information.

       If neither EXIT_STATUS or EXIT_SIGNAL is given for a failed process, it
       is  because  the process failed to spawn (for example, file not found).
       See the system logs for the error.

       init(8) will wait for all services started by this event to be running,
       all  tasks  started by this event to have finished and all jobs stopped
       by this event to be stopped before allowing the job to  continue  stop-

       This  allows  jobs  to depend on other jobs, safely stopping themselves
       before their dependency goes away.  This event  is  typically  combined
       with the started(7) event by services.

       Job configuration files may use the export stanza to export environment
       variables from their own environment  into  the  stopping  event.   See
       init(5) for more details.

       A service that wishes to depend on another service might use:

              start on started apache
              stop on stopping apache

       A task that must be run before another task or service is stopped might

              start on stopping postgresql RESULT=ok