Linux PEX network installed: No bootable Device__linux

After learning the PEX network unattended installed, the following error occurred during the installation operation:

So start checking from the DHCP server, Mygod found DHCP and TFTP service not open

[Root@svr7 tftpboot]# systemctl status dhcpd
dhcpd.service-dhcpv4 Server Daemon
   loaded:loaded (/usr/lib/syst Emd/system/dhcpd.service; Disabled Vendor preset:disabled)
   active:inactive (dead)
     DOCS:MAN:DHCPD (8)
           man:dhcpd.conf (5)

[root@svr7 tftpboot]# systemctl Restart DHCPD [root@svr7 tftpboot]# systemctl Restart TFTPD

After opening the service, the normal network installed.

PostScript :
PEX network installed in Linux, because the comprehensive, more details, error prone, but must check to find this error. In general, there are the following (not limited to the following) where the problem arises:

Related services: DHCPD, httpd, yum, tftp
Involved files: TFTP service directory of related configuration files and startup files
Profile: Configuration file parameters are correct