Since there’s no /dev/xconsole on LXC containers, a quick fix for this:

rsyslogd-2039: Could not open output pipe ‘/dev/xconsole’ [try http://www.rsyslog.com/e/2039 ]

in /var/log/syslog is to:

simply comment it out (in /etc/rsyslog.d/50-default.conf) as follows:

# daemon.*;mail.*;
# news.err;
# *.=debug;*.=info;
# *.=notice;*.=warn |/dev/xconsole

Source: http://www.techsupportforum.com/forums/f64/issue-with-rsyslog-ubuntu-server-12-04lts-650063.html