[Ceilometer] To collect the bandwidth of Neutron L3 router

Ceilometer component in OpenStack is a great project for me to study further in depth I think. I am not going to introduce it because it's not the scope of this post. Instead, I only want to list some resources about Ceilometer to collect the bandwith/traffic accounting of Neutron L3 router.

From this offical document: https://wiki.openstack.org/wiki/Neutron/Metering/Bandwidth
we can know that the actual implementation to collect the bandwidth of Neutron L3 router is based on iptables.

We can use the neutron command to list the related metering rules and labels
$ neutron meter-label-list
$ neutron meter-label-rule-list

The "neutron-meter-agent" will collect the traffic accounting in the iptables chain and push to oslo-messaging. So the following command can show the traffic accounting in Neutron L3 router


root@sn1:~# nova --os-project-name mickey list


root@sn1:~# nova show bb1879bd-1202-4007-9376-41be30e07ae9


root@sn1:~# neutron --os-tenant-name mickey router-list


root@node-5:~# neutron meter-label-rule-list


root@node-5:~# neutron meter-label-rule-show d31f0b9e-8824-4857-a2dc-19f237723f0c


root@node-5:~# neutron meter-label-rule-show 1ae289ef-687e-4303-8036-9a7566dd5365


So, we need to find the metering labels: "neutron-meter-l-78675a84" and "neutron-meter-l-b88c5977"

root@cn3:~#  ip netns exec qrouter-b1741371-ee12-46a1-831b-d3b35429d7c8 iptables -nL -v -x



root@cn3:~# ip netns exec qrouter-b1741371-ee12-46a1-831b-d3b35429d7c8 iptables -t nat -S




Here is the example to query the metering data in Ceilometer
$ root@node-5:~# ceilometer statistics -m bandwidth -q "resource=b88c5977-4445-4f19-9c8f-3d92809f844e;timestamp>=2016-03-01T00:00:00" --period 86400



P.S:
The following article is to introduce "Traffic Accounting with Linux IPTables" which can make us more understand it.
http://www.catonmat.net/blog/traffic-accounting-with-iptables/
https://wiki.openstack.org/wiki/Neutron/Metering/Bandwidth