In Centos 7 the dhcp log file is sent to /var/log/messages
This can be redirected to another file
emacs /etc/dhcp/dhcpd.conf
Replace this line
log-facility local7;
With this
log-facility local6;
Now modify /etc/rsyslog.conf
emacs /etc/rsyslog.conf
Add this line right after local7.*
# Redirect dhcpd log messages to another logfile
local6.* /var/log/dhcpd/dhcpd.log
Modify this line
# Log anything (except mail) of level info or higher.
# Don't log private authentication messages!
*.info;mail.none;authpriv.none;cron.none /var/log/messages
With this
*.info;mail.none;authpriv.none;cron.none;local6.none /var/log/messages
So you only appended ;local6.none
Create the new directory where the new dhcp log file will be stored
mkdir /var/log/dhcpd
Now restart rsyslog
systemctl restart rsyslog