Send postgresql log to syslog

Enable syslog to listen to udp port 514 (the port number can be changed to suit your need)

# vi /etc/rsyslog.conf

$ModLoad imudp

$UDPServerRun 514

Restart rsyslog

# systemctl restart rsyslog

Check if rsyslog is now listening to 514 udp port

# ss -tulpn | grep 514

udp    UNCONN     0      0                      *:514                   *:*      users:(("rsyslogd",15281,3))

udp    UNCONN     0      0                     :::514                  :::*      users:(("rsyslogd",15281,4))

Set postgres to log to syslog

# vi /var/lib/pgsql/9.5/data/postgresql.conf

log_destination = 'syslog'

Restart postgres

# systemctl restart postgresql-9.5

Check if your postgres log is now being logged by syslog

# tail -f /var/log/messages 

...

Dec 11 08:39:21 mypostgres postgres[21518]: [3-1] < 2018-12-11 08:39:21.932 UTC >LOG:  autovacuum launcher started