Comment 4 for bug 1024487

From what I know of rsyslog, the rate limiting was introduced by default in rsyslog < 7 and then later refactored in rsyslog v7+.
The overall rate-limiting functions can be removed and or set to 0 with the following variables in the /etc/rsyslog.conf:

$SystemLogRateLimitInterval 0
$SystemLogRateLimitBurst 0

I proposed a small change in the stack.sh which will set the rsyslog rate-limits to 0.
https://review.openstack.org/#/c/30783/

The change will make rsyslog handle all of the messages that are thrown at it.