Open Stack

Thank you everyone! You’re really helpful.

 

Best regards,

Rui Mao

 

发件人: openstack-bounces+maorui2k=163.com at lists.openstack.org [mailto:openstack-bounces+maorui2k=163.com at lists.openstack.org] 代表 Cynthia Lopes
发送时间: 2016年5月20日 03:21
收件人: Rick Jones <rick.jones2 at hpe.com>
抄送: openstack at lists.openstack.org
主题: Re: [Openstack] Does compute node require provider network?

 

Hello, I totally agree with Rick, the guide scheme must be assuming DVR.

However, on the 'Networking service' session of the same guide it is not assuming DVR, it does not even mention it. I think this could be a documentation issue...

Rui, I guess DVR is disabled by default, you can check in you neutron.conf in default session router_distributed = False

For more details on the networking configuration for you each scenario check this out: http://docs.openstack.org/mitaka/networking-guide/

 

Hope this is helpful, good luck :)

 

Kind regards,

Cynthia Lopes do Sacramento

 

2016-05-19 18:33 GMT+01:00 Rick Jones <rick.jones2 at hpe.com <mailto:rick.jones2 at hpe.com> >:

On 05/18/2016 09:51 PM, Rui Mao wrote:

http://docs.openstack.org/mitaka/install-guide-ubuntu/environment-networking.html#environment-networking

In the guide, the compute node requires a provider network connection,
and the neutron run in controller node.

But per my understanding, all VMs access the internet via NAT, and the
nova node has no internet access requirement in production environment.

Anything I missed or misunderstood?


I took a quick look at that diagram.  It may be assuming DVR (Distributed Virtual Router) is enabled.

"Before" there would be a neutron private (aka Guest) network running between all the computes and the Neutron network nodes.  An instance (VM) would access the outside world (Internet, whatnot) by having its traffic go across the Guest VLAN to a controller, the virtual router on the controller and such would do the NAT, and off the traffic goes on the external VLAN.

Today that is called "Central(ized?) Virtual Router or CVR.

Since Liberty (or Kilo if the OpenStack provider backported?) there has also been support for Distributed Virtual Router (DVR).  In this mode, when a floating IP is associated with a port of the instance, the NAT is handled on the compute node.  This allows traffic levels to scale much, Much, MUCH better by not having to go through the central Neutron network node(s).  (SNAT for ports/instances without floating IPs still happens in the Neutron network node).

But it does mean the compute node(s) must also have a connection to the external VLAN just like a controller node.

I assume that if you do not enable DVR, you also do not need the external provider network to be populated to the compute nodes.

happy benchmarking,

rick jones



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