Ubuntu service downloading procedures
The server with Ubuntu 16.04 is asterisk with dahdi module. When rebooting the server asterisk begins until the initialization of dahdi. The manual chan_dahdi module is not loaded. Only with dahdi_cfg can the module download asterisk. The question is, how do dahdi_cfg be implemented first and then launched asterisk?
Ubuntu has load folders in different modes
/etc/rc0.d /etc/rc1.d /etc/rc2.d /etc/rc3.d /etc/rc4.d /etc/rc5.d /etc/rc6.d
5 Multi-user graphics, 3 multi-user network mode (usually servers). The folders contain references to services (usually located in /etc/init.d) which are loaded alphabetically. For the service to start before another, it's enough to give him the name of a reference that's going to be on the alphabet before another service.
/etc/rc3.d ... S10dahdi_cfg -> ../init.d/dahdi_cfg* S20asterisk -> ../init.d/asterisk*