Verified in 4.3.7

From 4.3.7, we need use a new method to enable fluentd send logs to external syslog server

1) create a configmap named syslog

echo '<store>
     @type syslog
     remote_syslog rsyslogserver.openshift-logging.svc.cluster.local
     port 514
     hostname $hostname
     remove_tag_prefix tag
     tag_key ident,systemd.u.SYSLOG_IDENTIFIER
     facility local0
     severity info
     use_record true
     payload_key message
</store>' >syslog.conf
oc create configmap syslog --from-file=syslog.conf -n openshift-logging

2) restart fluentd pod
oc delete pod --selector logging-infra=fluentd


For more detail, refer to https://docs.openshift.com/container-platform/4.3/logging/config/cluster-logging-log-forwarding.html.

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2020:0858