# cat /etc/supervisord.d/thumbor.ini
[fcgi-program:thumbor]
command=/usr/bin/%(program_name)s -c /etc/%(program_name)s.conf -f /run/supervisor/%(program_name)s.sock
socket=unix:///run/supervisor/%(program_name)s.sock
socket_owner=h2o
process_name=%(program_name)s-%(process_num)s
autostart=true
autorestart=true
numprocs=4
startretries=3
stopsignal=TERM
user=h2o
stdout_logfile=/var/log/supervisor/%(program_name)s-%(process_num)s-stdout.log
stderr_logfile=/var/log/supervisor/%(program_name)s-%(process_num)s-stderr.log

# ls -lah /run/supervisor/thumbor.sock
srwx------. 1 h2o root 0 Jun  5 14:49 /run/supervisor/thumbor.sock

# /usr/bin/thumbor -c /etc/thumbor.conf -d -f /run/supervisor/thumbor.sock
Traceback (most recent call last):
  File "/usr/bin/thumbor", line 11, in <module>
    load_entry_point('thumbor==6.3.2', 'console_scripts', 'thumbor')()
  File "/usr/lib64/python2.7/site-packages/thumbor/server.py", line 130, in main
    run_server(application, context)
  File "/usr/lib64/python2.7/site-packages/thumbor/server.py", line 102, in run_server
    with open(context.server.fd, 'r') as sock:
IOError: [Errno 6] No such device or address: '/run/supervisor/thumbor.sock'