[openstack-dev] [neutron] Neutron scaling datapoints?

joehuang joehuang at huawei.com
Thu Apr 9 02:34:13 UTC 2015

Hi, Neil,

>From theoretic, Neutron is like a "broadcast" domain, for example, enforcement of DVR and security group has to touch each regarding host where there is VM of this project resides. Even using SDN controller, the "touch" to regarding host is inevitable. If there are plenty of physical hosts, for example, 10k, inside one Neutron, it's very hard to overcome the "broadcast storm" issue under concurrent operation, that's the bottleneck for scalability of Neutron. 

We need layered architecture in Neutron to solve the "broadcast domain" bottleneck of scalability. The test report from OpenStack cascading shows that through layered architecture "Neutron cascading", Neutron can supports up to million level ports and 100k level physical hosts. You can find the report here: http://www.slideshare.net/JoeHuang7/test-report-for-open-stack-cascading-solution-to-support-1-million-v-ms-in-100-data-centers

"Neutron cascading" also brings extra benefit: One cascading Neutron can have many cascaded Neutrons, and different cascaded Neutron can leverage different SDN controller, maybe one is ODL, the other one is OpenContrail.

----------------Cascading Neutron-------------------
            /         \
--cascaded Neutron--   --cascaded Neutron-----
       |                  |
---------ODL------       ----OpenContrail--------

And furthermore, if using Neutron cascading in multiple data centers, the DCI controller (Data center inter-connection controller) can also be used under cascading Neutron, to provide NaaS ( network as a service ) across data centers.

---------------------------Cascading Neutron--------------------------
            /            |          \
--cascaded Neutron--  -DCI controller-  --cascaded Neutron-----
       |                 |            |
---------ODL------           |         ----OpenContrail--------
--(Data center 1)--   --(DCI networking)--  --(Data center 2)--

Is it possible for us to discuss this in OpenStack Vancouver summit?

Best Regards
Chaoyi Huang ( Joe Huang )

-----Original Message-----
From: Neil Jerram [mailto:Neil.Jerram at metaswitch.com] 
Sent: Thursday, April 09, 2015 12:27 AM
To: openstack-dev at lists.openstack.org
Subject: [openstack-dev] [neutron] Neutron scaling datapoints?

My team is working on experiments looking at how far the Neutron server will scale, with increasing numbers of compute hosts and VMs.  Does anyone have any datapoints on this that they can share?  Or any clever hints?

I'm already aware of the following ones:

 118 compute hosts
 80 Neutron server processes (10 per core on each of 8 cores, on the  controller node)
 27,000 VMs - but only after disabling all security/iptables

 1000 hosts
 5000 VMs
 3 Neutron servers (via a load balancer)  But doesn't describe if any specific configuration is needed for this.
 (Other than using OpenContrail! :-))

Many thanks!

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