gistfile1.txt

$ docker run --link syslog:syslog ubuntu:14.04 bash -c \
>     'echo netcat:"hello remote tcp" \
>          | nc -w 1 $SYSLOG_PORT_514_TCP_ADDR $SYSLOG_PORT_514_TCP_PORT'

$ docker run --link syslog:syslog ubuntu:14.04 bash -c \
>     'echo netcat:"hello remote udp" \
>          | nc -w 1 $SYSLOG_PORT_514_UDP_ADDR $SYSLOG_PORT_514_UDP_PORT'

$ docker run --link syslog:syslog ubuntu:14.04 bash -c \
>     'logger -n $SYSLOG_PORT_514_TCP_ADDR -P $SYSLOG_PORT_514_TCP_PORT \
>          hello remote tcp'

$ docker run --link syslog:syslog ubuntu:14.04 bash -c \
>     'logger -d -n $SYSLOG_PORT_514_UDP_ADDR -P $SYSLOG_PORT_514_UDP_PORT \
>          hello remote udp'

$ docker exec -t syslog tail /var/log/syslog
Jun  2 23:35:50 3acd7e6b6bff rsyslogd: [origin software="rsyslogd" swVersion="7.4.4" x-pid="1" x-info="http://www.rsyslog.com"] start
Jun  2 23:35:50 3acd7e6b6bff rsyslogd: imklog: cannot open kernel log (/proc/kmsg): Operation not permitted.
Jun  2 23:35:50 3acd7e6b6bff rsyslogd-2145: activation of module imklog failed [try http://www.rsyslog.com/e/2145 ]
Jun  2 23:35:50 3acd7e6b6bff rsyslogd: rsyslogd's groupid changed to 104
Jun  2 23:35:50 3acd7e6b6bff rsyslogd: rsyslogd's userid changed to 101
Jun  2 23:35:50 3acd7e6b6bff rsyslogd-2039: Could no open output pipe '/dev/xconsole': No such file or directory [try http://www.rsyslog.com/e/2039 ]
Jun  2 23:36:22 172.17.0.113 netcat: hello remote tcp
Jun  2 23:36:33 172.17.0.114 netcat: hello remote udp

So, the issue and a workaround described by this link https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=684264