I recently set up Ubuntu Natty with PHP5-FPM, Gearman, and Supervisor. I\'ve edited my Supervisord config to run a Gearman worker.
[program:gearman]
command=/us
I always include the stopsignal config option for my supervisor config files. This allows the gearman process to be killed when a stop is requested. Try this:
[program:gearman]
command=/usr/bin/php php_gearman_worker.php
numprocs=1
directory=/root/sandbox
stdout_logfile=/root/sandbox/supervisord.log
environment=GEARMAN_USER=gearman
autostart=true
autorestart=true
user=gearman
stopsignal=KILL