[openstack-dev] Quantum L3 router, mixin or plugin?

Alan Kavanagh alan.kavanagh at ericsson.com
Fri Nov 9 22:39:11 UTC 2012


+1 yes I think this is starting to make sense, I put a slide together to show the relationship between the Virtual Network Services and the basic network connectivity model. Im sure other Virtual Network Services exist, this was just a list I though made sense to begin with, so its not a complete list.

I too am willing to work on the blueprint to make sure we put the right Quantum Network Service Framework in place, that to me is paramount so can extend this quite simply after that.

[cid:image002.png at 01CDBEA1.1FDF4370]
From: Bob Melander (bmelande) [mailto:bmelande at cisco.com]
Sent: November-09-12 6:43 AM
To: Dan Wendlandt; Eugene Nikanorov; Gary Kotton; Sasha Ratkovic
Cc: OpenStack Development Mailing List
Subject: Re: [openstack-dev] Quantum L3 router, mixin or plugin?

Ok, I'm willing to work on this and I've created a blueprint to kick it off (https://blueprints.launchpad.net/quantum/+spec/quantum-l3-routing-plugin)

I too think VRRP (and some other features) would be nice to add. However, the first steps would be to take the inherited mixin and transform that into a plugin. That ought to be possible with fairly limited effort. Though there are some dependencies that need to be sorted out. In particular, core plugin methods like  create_network(...)make calls to mixin functions such as _process_l3_create(...), _extend_network_dict_l3(...), _process_l3_update(...):



self._process_l3_create(context, network['network'], net['id'])

...

self._extend_network_dict_l3(context, net)

This does not immediately map to the service insertion schematic:

[ServiceIntegration.jpg]
/ Bob




From: Dan Wendlandt <dan at nicira.com<mailto:dan at nicira.com>>
Reply-To: OpenStack Development Mailing List <openstack-dev at lists.openstack.org<mailto:openstack-dev at lists.openstack.org>>
Date: torsdag 8 november 2012 21:03
To: OpenStack Development Mailing List <openstack-dev at lists.openstack.org<mailto:openstack-dev at lists.openstack.org>>
Subject: Re: [openstack-dev] Quantum L3 router, mixin or plugin?

Yes, being able to implement the L3 stuff independent of the core plugin (rather than as a mixin, tightly bound to the core plugin) was always the plan.  We did it as a mix-in for Folsom, as we didn't have time for the multi-service framework, but wanted to deliver L3 capabilities.  You can see the blueprint for this, which is targeted at G-1:

I don't think anyone has signed up to do the work to port the L3 API to this new framework, so feel free to create a blueprint and add a dependency to the above blueprint.

dan

On Thu, Nov 8, 2012 at 5:33 AM, Bob Melander (bmelande) <bmelande at cisco.com<mailto:bmelande at cisco.com>> wrote:
In the wake of the recent discussion about service insertion, which seems to have landed in a decision to make each type of service (like LBaaS, FW, ...) a separate plugin, I want to raise the issue whether this approach shouldn't also be adopted for L3 router functionality. This is not the case now, where instead the server side is implemented as a L3_NAT_db_mixin class that basically each plugin inherits. The actual routing is implemented through the separate L3 agent (L3NATagent class) that relies on linux namespaces, the kernel IP forwarding functionality and IP tables.


My concern about this is the following: Suppose one would like to replace (or complement) that router implementation with something else, e.g., use a separate hardware-based router or add additional features like VRRP to the implementation. As long as the changes can be contained within the l3 agent (while honoring the normal interface), it is fairly simple to just replace the default one with the extended l3 agent in the deployment. However, if the desired functionality requires changes to the "server side", i.e.,  the L3_NAT_db_mixin class, the situation gets much more tricky since the mixin is essentially baked into the core plugin.


A way around this problem could be to provide the l3 routing functionality as a separate plugin, just as there will be separate plugins for LBaaS, FW, etc. With L3 routing also as a separate plugin, it seems to me it would be simpler to provide different such implementations, largely independent of (L2) core plugin but also to introduce additional L3 specific extensions.



What is your view on this?

/ Bob

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~~~~~~~~~~~~~~~~~~~~~~~~~~~
Dan Wendlandt
Nicira, Inc: www.nicira.com<http://www.nicira.com>
twitter: danwendlandt
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