<div dir="ltr"><div>Hi,<br><br></div><div>thanks for your reply irena and salvatore.<br><br></div><div>Currently, we're targeting 4 backends : bagpipe (the ref impelmentations compatible with other ref implementations of neutron), ODL, contrail and nuage.<br></div><div>Contrail and bagpipe work with networks attachments to a bgpvpn connection, while ODL and Nuage work with routers attachments. We even start thinking about port attachments [1]<br>Moreover, ODL needs a RD attribute that won't be supported by other backends.<br></div><div><br>I think that each backend should be able to manage each kind of attachment in the future, depending on the will of the backend dev team. But in a firts step, we have to manage the capacity of each backend.</div><div><br>So, indeed, the managment of attachments to a bgpvpn connection through the use of extensions will expose backend capacity. And I agree that it's not the good way, since when moving from one cloud to another, the API will change depending on the backend.<br><br></div><div>So I see two ways to solve this issue :<br></div><div>1-In first releases, backends that don't support a feature will through a '"NotImplemented" exception when the feature will be called through the API; We still have an inconsistent API, but hopefully, this gone be temporary.<br></div><div>2-reducing the scope of the spec [2] and having less compatible backends, and a smaller community for the bgpvpn project.<br></div><div><br>[1]<a href="https://blueprints.launchpad.net/bgpvpn/+spec/port-association">https://blueprints.launchpad.net/bgpvpn/+spec/port-association</a><br>[2]<a href="https://review.openstack.org/#/c/177740/">https://review.openstack.org/#/c/177740/</a><br><br></div><div>regards,<br><br></div><div>Mathieu<br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Aug 19, 2015 at 1:55 PM, Irena Berezovsky <span dir="ltr"><<a href="mailto:irenab.dev@gmail.com" target="_blank">irenab.dev@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Current VPNaaS Service Plugin inherits from VpnPluginRpcDbMixin, which is not required for some vendor solutions, since L3 is implemented without leveraging L3 Agents to manage router namespaces (ODL, MidoNet, etc).<div>I guess if Mixin usage will be changed to conditional RPC support based on drivers requirements, follow what Salvatore suggested makes perfect sense.<div><div class="h5"><br><div><div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Aug 19, 2015 at 11:06 AM, Salvatore Orlando <span dir="ltr"><<a href="mailto:salv.orlando@gmail.com" target="_blank">salv.orlando@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div>my 0.02€ on the matter inline.<br><br></div>Regards,<br></div>Salvatore<br><div><div><div><div class="gmail_extra"><br><div class="gmail_quote"><span>On 18 August 2015 at 23:45, Mathieu Rohon <span dir="ltr"><<a href="mailto:mathieu.rohon@gmail.com" target="_blank">mathieu.rohon@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div><div><div>hi brandon,<br><br></div>thanks for your answer.<br><br></div><div>my answers inline,<br><br></div><div></div> <br></div></div><div><div><div></div></div></div><div class="gmail_extra"><br><div class="gmail_quote"><span>On Tue, Aug 18, 2015 at 8:53 PM, Brandon Logan <span dir="ltr"><<a href="mailto:brandon.logan@rackspace.com" target="_blank">brandon.logan@rackspace.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr" style="font-size:12pt;color:#000000;background-color:#ffffff;font-family:Calibri,Arial,Helvetica,sans-serif">
<p>So let me make sure I understand this. You want to do a separate service plugin for what would normally be separate drivers under one service plugin. The reasons for this are:<br>
</p>
<p><br>
</p>
<p>1. You dont want users the ability to choose the type, you want it always to be the same one<br></p></div></blockquote></span></div></div></div></blockquote></span><div>While in theory it is be possible to have multiple BGPVPN providers in the same deployment, there are control and data plane aspects that the service type framework at the moment cannot deal with it. Mathieu brought some examples in the bug report. The bottom line appears to be that the choice of the l3 service plugin (or whatever serves l3 in your deployment) also dictates the choiche of the BGPVPN service provider to employ.<br></div><span><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><span><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr" style="font-size:12pt;color:#000000;background-color:#ffffff;font-family:Calibri,Arial,Helvetica,sans-serif"><p>
</p>
<p>2. Some types do want to be the source of truth of the data stored, instead of it being the service plugin database.<br></p></div></blockquote></span></div></div></div></blockquote></span><div>This point has little to do with service types. It's about the fact that plugins are not required to implemented the various db mixins in neutron.db and therefore not required to use the neutron DB. <br></div><span><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><span><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr" style="font-size:12pt;color:#000000;background-color:#ffffff;font-family:Calibri,Arial,Helvetica,sans-serif"><p>
</p>
<p><br>
</p>
<p>First, let me address the possibility of a solution using one service plugin and multiple drivers per type:<br>
</p>
<p><br>
</p>
<p>I think that you can overcome #1 in the instantiation of the service plugin to check if there are more than 1 provider active, if so you can just throw an exception saying you can only have 1. I'd have to look at it more to see if there are any caveats
to this, but I think that would work.<br>
</p>
<p><br>
</p>
<p>For #2, assuming #1 works, then the drivers that are defined can have some boolean that they set that will tell the plugin whether they are the source of truth or not, and depending on that you can store the data in the service plugin's db or just pass the
data along, also pass GET requests to the drivers as well.<br>
</p>
<p></p></div></blockquote><div><br></div></span><div>I agree that those workarounds will surely works but I wonder what is the meaning of a service plugin/type that can only support one service provider? can't the service plugin be the service provider directly? <br></div></div></div></div></blockquote><div><br></div></span><div>I believe there is some value, but I am not able to quantify it at the moment.<br></div><div>- A single service plugin also implies (more or less) a common user-facing APIs. I really don't want to end up in a conditons where the user API looks different (or the workflow is different) according to what's backing the neutron BGPVPN implementation<br></div><div>- A single service plugin provides a commonplace for all the boilerplate management logic. This works for most drivers, but not for those who don't rely on neutron DB as a data source (unless you manage to build a sqlalchemy dialect for things such as opencontrail APIs, but I seriously doubt that it would be feasible)<br></div><div>- Distinct service plugins might lead to different workflows. This is not necessarily a bad thing, because integration for some backends might need it. However this means that during review phase particular attention should be paid to ensure the behaviour of each service plugin respects the API specification.<br></div><span><div> <br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div><br>The reasons why I'm considering this change are :<br><br>1. I'm not sure we would have some use cases
where we would be able to choose one bgpvpn backend independently from the provider of the core plugin (or a mech driver in the ML2 case)
and/or the router plugin.<br><div>If one use ODL to manage its core resources, he won't be able to use nuage or contrail to manage its bgpvpn connection. <br></div><div>The bgpvpn project is more about having a common API than having the capacity to mix backends. At least for the moment.<br></div></div></div></div></div></blockquote><div><br></div></span><div>I agree with this; but this problem exists regardless of whether you have a single service plugin with drivers or multiple service plugins. You are unlikely to be able to use the contrail BGPVPN service plugin is core and l3 are managed by ODL, I think.<br></div><span><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div><div></div><br>2.
I'm also considering that each plugin, which would be backend dependent, could declare what features it
supports through the use of extensions. </div></div></div></div></blockquote><div><br></div></span><div>Unfortunately extensions are the only way to declare supported capabilities at the moment. But please - don't end up allowing each service plugin exposing a different API.<br></div><span><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div>Each plugin would be a "bgpvpn"
service type, and would implement the bgpvpn extension, but some of them
could extend the bgpvpn_connection resource with other extensions also
hosted in the bgpvpn project. Since some backends only support
attachment of networks to a bgpvpn_connection, others support attachment
of routers, and others both attachments, I'm considering having an extension for
each type of attachment. Then the bgpvpn plugin declares what extensions it
supports and the end user can act accordingly depending on the scan of
neutron extensions.<br></div></div></div></div></blockquote><div><br></div></span><div>This is not good. It appears that you are forced to leak backend details to API consumers. Is it possible for you to share more context on why this is necessary and there's nothing that can be done to avoid it?<br></div><span><div><br> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div></div><div>By moving to one plugin per backend, the load of extensions would be done by the neutron framework, natively. We won't have to scan each service providers to see what extensions it supports, as it is done by the ML2 extension manager.<br></div><div>But I agree that with your workaround, of allowing only one service provider, we can easily scan this driver for its extensions.<br></div></div></div></div></blockquote><div><br></div></span><div>Indeed. But still, backends like contrail will have to provide their own service plugin I think. Which might be ok. All the backends which leverage the neutron DB might use the "driverized" plugin, and the others can supply their own service plugin. <br></div><div><div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div></div><span><div><br></div><div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr" style="font-size:12pt;color:#000000;background-color:#ffffff;font-family:Calibri,Arial,Helvetica,sans-serif"><p><br>
</p>
<p>As for making a service plugin for each type, I don't see why that wouldn't work. It seems a bit overkill to me though because you'd probably end up having 2 base classes for every service plugin type, one for using the service plugin database and another
for the data source of truth being external. Probably a better way to do this, I'm sure I'm oversimplifying. </p></div></blockquote></span><div>You're right, and you're not oversimplifying. With this change, the
bgpvpn framework will only manage API extensions and the DB layer if
needed. And we don't want this framework to be complicated, in a first step, we just want to have a consistent API for every backends. <br></div></div></div></div></blockquote><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div></div><span><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr" style="font-size:12pt;color:#000000;background-color:#ffffff;font-family:Calibri,Arial,Helvetica,sans-serif"><p>I don't see much technical reasons why you couldn't do this, though. It's just inconsistent and might cause some confusion. I'd need to spend some
time on it to really have an educated opinion.<br>
</p>
</div></blockquote></span><div>The fact that this change will lead to inconsistency between usage of each service plugins is a valid point and might be enough to not do it and instead limiting the bgpvpn <span></span>service plugin to be able to only load one service driver for the moment. Which is also inconsistent with some other service plugins, but probably less.<br><br></div><div>thanks brandon.<br><br></div><div>Mathieu<br></div><div><br> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span><div dir="ltr" style="font-size:12pt;color:#000000;background-color:#ffffff;font-family:Calibri,Arial,Helvetica,sans-serif">
<p>Thanks,<br>
Brandon<br>
</p>
<div style="color:rgb(33,33,33)">
<hr style="display:inline-block;width:98%">
<div dir="ltr"><font style="font-size:11pt" color="#000000" face="Calibri, sans-serif"><b>From:</b> Mathieu Rohon <<a href="mailto:mathieu.rohon@gmail.com" target="_blank">mathieu.rohon@gmail.com</a>><br>
<b>Sent:</b> Tuesday, August 18, 2015 7:13 AM<br>
<b>To:</b> OpenStack Development Mailing List<br>
<b>Subject:</b> [openstack-dev] [Neutron][bgpvpn] Service Plugin vs Service driver</font>
<div> </div>
</div><div><div>
<div>
<div dir="ltr">Adding the related subject :)<span></span><br>
<div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Tue, Aug 18, 2015 at 10:35 AM, Mathieu Rohon <span dir="ltr">
<<a href="mailto:mathieu.rohon@gmail.com" target="_blank">mathieu.rohon@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">
<div>
<div>
<div>
<div>
<div>Hi all,<br>
<br>
</div>
The current bgpvpn implementation is using the service type framework, with a service plugin and one or more service providers.<br>
</div>
<br>
After registering the bug [1], I wonder if we would rather use a service plugin per implementation type (bagpipe, ODL, OpenContrail, Nuage...) which handles API calls, instead of having one service plugin which forwards API calls to a service driver depending
on the provider chosen by the end user.</div>
<div><br>
</div>
I would like to better understand what would be the main drawbacks of such a move apart from the fact that a deployment would be tightly coupled to a bgpvpn plugin, and multiple implementations of the plugin couldn't coexist.<br>
<br>
</div>
Thanks,<br>
<br>
</div>
Mathieu<br>
<br>
[1]<a href="https://bugs.launchpad.net/bgpvpn/+bug/1485515" target="_blank">https://bugs.launchpad.net/bgpvpn/+bug/1485515</a><br>
<div>
<div>
<div></div>
</div>
</div>
</div>
</blockquote>
</div>
<br>
</div>
</div>
</div>
</div>
</div></div></div>
</div>
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