Open Stack

----- Original Message -----
> From: "joehuang" <joehuang at huawei.com>
> To: "OpenStack Development Mailing List (not for usage questions)" <openstack-dev at lists.openstack.org>
> Sent: Sunday, April 12, 2015 1:20:48 PM
> Subject: Re: [openstack-dev] [neutron] Neutron scaling datapoints?
> 
> 
> 
> Hi, Kevin,
> 
> 
> 
> I assumed that all agents are connected to same IP address of RabbitMQ, then
> the connection will exceed the port ranges limitation.
> 
https://news.ycombinator.com/item?id=1571300

"TCP connections are identified by the (src ip, src port, dest ip, dest port) tuple."

"The server doesn't need multiple IPs to handle > 65535 connections. All the server connections to a given IP are to the same port. For a given client, the unique key for an http connection is (client-ip, PORT, server-ip, 80). The only number that can vary is PORT, and that's a value on the client. So, the client is limited to 65535 connections to the server. But, a second client could also have another 65K connections to the same server-ip:port."

> 
> For a RabbitMQ cluster, for sure the client can connect to any one of member
> in the cluster, but in this case, the client has to be designed in fail-safe
> manner: the client should be aware of the cluster member failure, and
> reconnect to other survive member. No such mechnism has been implemented
> yet.
> 
> 
> 
> Other way is to use LVS or DNS based like load balancer, or something else.
> If you put one load balancer ahead of a cluster, then we have to take care
> of the port number limitation, there are so many agents will require
> connection concurrently, 100k level, and the requests can not be rejected.
> 
> 
> 
> Best Regards
> 
> 
> 
> Chaoyi Huang ( joehuang )
> 
> 
> 
> From: Kevin Benton [blak111 at gmail.com]
> Sent: 12 April 2015 9:59
> To: OpenStack Development Mailing List (not for usage questions)
> Subject: Re: [openstack-dev] [neutron] Neutron scaling datapoints?
> 
> The TCP/IP stack keeps track of connections as a combination of IP + TCP
> port. The two byte port limit doesn't matter unless all of the agents are
> connecting from the same IP address, which shouldn't be the case unless
> compute nodes connect to the rabbitmq server via one IP address running port
> address translation.
> 
> Either way, the agents don't connect directly to the Neutron server, they
> connect to the rabbit MQ cluster. Since as many Neutron server processes can
> be launched as necessary, the bottlenecks will likely show up at the
> messaging or DB layer.
> 
> On Sat, Apr 11, 2015 at 6:46 PM, joehuang < joehuang at huawei.com > wrote:
> 
> 
> 
> 
> 
> As Kevin talking about agents, I want to remind that in TCP/IP stack, port (
> not Neutron Port ) is a two bytes field, i.e. port ranges from 0 ~ 65535,
> supports maximum 64k port number.
> 
> 
> 
> " above 100k managed node " means more than 100k L2 agents/L3 agents... will
> be alive under Neutron.
> 
> 
> 
> Want to know the detail design how to support 99.9% possibility for scaling
> Neutron in this way, and PoC and test would be a good support for this idea.
> 
> 
> 
> "I'm 99.9% sure, for scaling above 100k managed node,
> we do not really need to split the openstack to multiple smaller openstack,
> or use significant number of extra controller machine."
> 
> 
> 
> Best Regards
> 
> 
> 
> Chaoyi Huang ( joehuang )
> 
> 
> 
> From: Kevin Benton [ blak111 at gmail.com ]
> Sent: 11 April 2015 12:34
> To: OpenStack Development Mailing List (not for usage questions)
> Subject: Re: [openstack-dev] [neutron] Neutron scaling datapoints?
> 
> Which periodic updates did you have in mind to eliminate? One of the few
> remaining ones I can think of is sync_routers but it would be great if you
> can enumerate the ones you observed because eliminating overhead in agents
> is something I've been working on as well.
> 
> One of the most common is the heartbeat from each agent. However, I don't
> think we can't eliminate them because they are used to determine if the
> agents are still alive for scheduling purposes. Did you have something else
> in mind to determine if an agent is alive?
> 
> On Fri, Apr 10, 2015 at 2:18 AM, Attila Fazekas < afazekas at redhat.com >
> wrote:
> 
> 
> I'm 99.9% sure, for scaling above 100k managed node,
> we do not really need to split the openstack to multiple smaller openstack,
> or use significant number of extra controller machine.
> 
> The problem is openstack using the right tools SQL/AMQP/(zk),
> but in a wrong way.
> 
> For example.:
> Periodic updates can be avoided almost in all cases
> 
> The new data can be pushed to the agent just when it needed.
> The agent can know when the AMQP connection become unreliable (queue or
> connection loose),
> and needs to do full sync.
> https://bugs.launchpad.net/neutron/+bug/1438159
> 
> Also the agents when gets some notification, they start asking for details
> via the
> AMQP -> SQL. Why they do not know it already or get it with the notification
> ?
> 
> 
> ----- Original Message -----
> > From: "Neil Jerram" < Neil.Jerram at metaswitch.com >
> > To: "OpenStack Development Mailing List (not for usage questions)" <
> > openstack-dev at lists.openstack.org >
> > Sent: Thursday, April 9, 2015 5:01:45 PM
> > Subject: Re: [openstack-dev] [neutron] Neutron scaling datapoints?
> > 
> > Hi Joe,
> > 
> > Many thanks for your reply!
> > 
> > On 09/04/15 03:34, joehuang wrote:
> > > 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.
> > 
> > I think I understand that in general terms - but can you be more
> > specific about the broadcast storm? Is there one particular message
> > exchange that involves broadcasting? Is it only from the server to
> > agents, or are there 'broadcasts' in other directions as well?
> > 
> > (I presume you are talking about control plane messages here, i.e.
> > between Neutron components. Is that right? Obviously there can also be
> > broadcast storm problems in the data plane - but I don't think that's
> > what you are talking about here.)
> > 
> > > 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
> > 
> > Many thanks, I will take a look at this.
> > 
> > > "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?
> > 
> > Most certainly, yes. I will be there from mid Monday afternoon through
> > to end Friday. But it will be my first summit, so I have no idea yet as
> > to how I might run into you - please can you suggest!
> > 
> > > Best Regards
> > > Chaoyi Huang ( Joe Huang )
> > 
> > Regards,
> > Neil
> > 
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> 
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> 
> 
> --
> Kevin Benton
> 
> __________________________________________________________________________
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> 
> 
> 
> --
> Kevin Benton
> 
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