This name is already in the /etc/hosts file. I am attempting to listen on localhost.

source local {
        network(localip(localhost) transport("tcp") port(1514) max_connections(100) log_fetch_limit(500) log_iw_size(10000) flags(no-multi-line,syslog-protocol) tags(uvic.local) keep-timestamp(no) );
};

and the /etc/hosts file has

127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4

and on reboot ...

05:13:28.891 host daemon.notice systemd[1]: syslog-ng.service: main process exited, code=exited, status=2/INVALIDARGUMENT
05:13:28.891 host daemon.err systemd[1]: Failed to start System Logger Daemon.
05:13:28.891 host daemon.notice systemd[1]: Unit syslog-ng.service entered failed state.
05:13:28.891 host daemon.warning systemd[1]: syslog-ng.service failed.
05:13:29.007 host daemon.info systemd[1]: syslog-ng.service holdoff time over, scheduling restart.
05:13:29.009 host daemon.info systemd[1]: Stopped System Logger Daemon.

05:13:29.009 host daemon.info systemd[1]: Starting System Logger Daemon...
05:13:29.190 host daemon.info syslog-ng[6366]: [05:13:29.189991] Error resolving hostname; host='localhost'
05:13:29.197 host daemon.notice systemd[1]: syslog-ng.service: main process exited, code=exited, status=2/INVALIDARGUMENT
05:13:29.197 host daemon.err systemd[1]: Failed to start System Logger Daemon.
05:13:29.197 host daemon.notice systemd[1]: Unit syslog-ng.service entered failed state.
05:13:29.198 host daemon.warning systemd[1]: syslog-ng.service failed.
05:13:29.345 host daemon.info systemd[1]: syslog-ng.service holdoff time over, scheduling restart.
05:13:29.346 host daemon.info systemd[1]: Stopped System Logger Daemon.

05:13:29.346 host daemon.info systemd[1]: Starting System Logger Daemon...
05:13:29.412 host daemon.info syslog-ng[6457]: [05:13:29.412745] Error resolving hostname; host='localhost'
05:13:29.415 host daemon.notice systemd[1]: syslog-ng.service: main process exited, code=exited, status=2/INVALIDARGUMENT
05:13:29.415 host daemon.err systemd[1]: Failed to start System Logger Daemon.
05:13:29.415 host daemon.notice systemd[1]: Unit syslog-ng.service entered failed state.
05:13:29.415 host daemon.warning systemd[1]: syslog-ng.service failed.
05:13:29.556 host daemon.info systemd[1]: syslog-ng.service holdoff time over, scheduling restart.
05:13:29.556 host daemon.info systemd[1]: Stopped System Logger Daemon.

05:13:29.557 host daemon.info systemd[1]: Starting System Logger Daemon...
05:13:29.623 host daemon.info syslog-ng[6487]: [05:13:29.623206] Error resolving hostname; host='localhost'
05:13:29.626 host daemon.notice systemd[1]: syslog-ng.service: main process exited, code=exited, status=2/INVALIDARGUMENT
05:13:29.626 host daemon.err systemd[1]: Failed to start System Logger Daemon.
05:13:29.626 host daemon.notice systemd[1]: Unit syslog-ng.service entered failed state.
05:13:29.626 host daemon.warning systemd[1]: syslog-ng.service failed.
05:13:29.806 host daemon.info systemd[1]: syslog-ng.service holdoff time over, scheduling restart.
05:13:29.807 host daemon.info systemd[1]: Stopped System Logger Daemon.

05:13:29.807 host daemon.info systemd[1]: Starting System Logger Daemon...
05:13:29.867 host daemon.info syslog-ng[6537]: [05:13:29.867292] Error resolving hostname; host='localhost'
05:13:29.870 host daemon.notice systemd[1]: syslog-ng.service: main process exited, code=exited, status=2/INVALIDARGUMENT
05:13:29.870 host daemon.err systemd[1]: Failed to start System Logger Daemon.
05:13:29.870 host daemon.notice systemd[1]: Unit syslog-ng.service entered failed state.
05:13:29.870 host daemon.warning systemd[1]: syslog-ng.service failed.

05:13:29.893 host daemon.info network[6435]: Bringing up loopback interface:  [  OK  ]

05:13:30.009 host daemon.info systemd[1]: syslog-ng.service holdoff time over, scheduling restart.
05:13:30.009 host daemon.info systemd[1]: Stopped System Logger Daemon.
05:13:30.009 host daemon.warning systemd[1]: start request repeated too quickly for syslog-ng.service
05:13:30.010 host daemon.err systemd[1]: Failed to start System Logger Daemon.
05:13:30.010 host daemon.notice systemd[1]: Unit syslog-ng.service entered failed state.
05:13:30.010 host daemon.warning systemd[1]: syslog-ng.service failed.

05:13:34.214 host daemon.info network[6435]: Bringing up interface eth0:  [  OK  ]

05:13:34.242 host daemon.info systemd[1]: Reached target Network.

05:13:37.651 host lpr.info cupsd[6665]: Listening to 127.0.0.1:631 on fd 10...

After this (when I can log in) a simple "service syslog-ng start" will correctly start the syslog-ng service.

the rsyslog package does have systemd unit file definitions of

Wants=network.target network-online.target
After=network.target network-online.target

but that might be Redhat's way of saying that systemd-journal is good enough when you don't have networking since

[Install]
WantedBy=multi-user.target

is also present meaning that rsyslog is only started when a multi-user boot is done.

Since the syslog-ng.service file also includes

[Install]
WantedBy=multi-user.target

I think that it is reasonable to add the unit definitions of

[Unit]

Wants=network.target network-online.target
After=network.target network-online.target

and the problem just goes away for normal boot up environments.

I think I'll post this as a packaging systemd unit file definition bug.

On 4/17/19 11:29 PM, Scheidler, Balázs wrote:

-- 
Evan Rempel                                      erempel@uvic.ca
Senior Systems Administrator                        250.721.7691
Data Centre Services, University Systems, University of Victoria