FRR is not logging to syslog as it has its own configuration file and logs to /var/log/frr/frr.log. IMHO it should log to syslog b/c with the current setup FRR messages cant be sent to a remote syslog service.
vyos@vyos# show system syslog
global {
facility all {
level all
}
facility protocols {
level debug
}
}
host 172.16.100.1 {
facility all {
level warning
}
}~$ ls -al /etc/rsyslog.d/ -rw-r--r-- 1 root root 1135 Jun 22 00:36 45-frr.conf -rw-r--r-- 1 root root 179 Oct 8 18:38 vyos-rsyslog.conf
cpo@LR1:~$ cat /etc/rsyslog.d/vyos-rsyslog.conf ## generated by syslog.py ## ## file based logging $outchannel global,/var/log/messages,262144,/usr/sbin/logrotate /etc/logrotate.d/vyos-rsyslog *.*;local7.debug :omfile:$global
cpo@LR1:~$ cat /etc/rsyslog.d/45-frr.conf
# The lines below cause all FRR daemons and process to go
# to /var/log/frr/frr.log, then drops the message so it does
# not also go to /var/log/syslog, so the messages are not duplicated
$outchannel frr_log,/var/log/frr/frr.log
if $programname == 'babeld' or
$programname == 'bgpd' or
$programname == 'eigrpd' or
$programname == 'frr' or
$programname == 'isisd' or
$programname == 'ldpd' or
$programname == 'nhrpd' or
$programname == 'ospf6d' or
$programname == 'ospfd' or
$programname == 'pimd' or
$programname == 'ripd' or
$programname == 'ripngd' or
$programname == 'watchfrr' or
$programname == 'zebra'
then :omfile:$frr_log
if $programname == 'babeld' or
$programname == 'bgpd' or
$programname == 'eigrpd' or
$programname == 'frr' or
$programname == 'isisd' or
$programname == 'ldpd' or
$programname == 'nhrpd' or
$programname == 'ospf6d' or
$programname == 'ospfd' or
$programname == 'pimd' or
$programname == 'ripd' or
$programname == 'ripngd' or
$programname == 'watchfrr' or
$programname == 'zebra'
then stop