[openstack-dev] [Quantum][LBaaS] Advanced Services Insertion

Youcef Laribi Youcef.Laribi at eu.citrix.com
Fri Nov 2 16:45:10 UTC 2012


Thanks Eugene, Salvatore for validating the current situation. Now  let me try to understand the changes we are proposing for incorporating LBaaS and other "advanced services".

All current "Core plugins" in Quantum like the "Linux Bridge" plugin implement the L2 core APIs, and some of these plugins also implement the L3 extension. Today, there can only be one "core plugin" running in Quantum. So, the total of the APIs supported will depend the core plugin that was configured.

Are we saying, that we will modify some of these core plugins to also implement the LBaaS extension, so they will expose the LBaaS APIs in addition to the L2 and L3 APIs ?  If not, is the proposal to modify Quantum to support more than one plugin at a time (a "core" one + others) ?

Youcef



From: Salvatore Orlando [mailto:sorlando at nicira.com]
Sent: Friday, November 2, 2012 2:11 AM
To: OpenStack Development Mailing List
Subject: Re: [openstack-dev] [Quantum][LBaaS] Advanced Services Insertion

Youcef,

I think that picture describes quite well the framework Quantum is already adopting for l2/l3 connectivity.
We could do down that route for LBaaS as well. However for supporting multiple providers we'll need to keep in mind that we might need some logic, within the Quantum plugin for dispatching to the appropriate agent.

With your permission, I will take your picture and use it in the service insertion wiki page, which I will update with the outcome of the recent discussions we had.

Salvatore
On 2 November 2012 07:22, Eugene Nikanorov <enikanorov at mirantis.com<mailto:enikanorov at mirantis.com>> wrote:
Hi Youcef,

The picture you've made is quite accurate.
My opinion is that we should adopt the same approach for lbaas, e.g. extension - plugin - agent - drivers.

Thanks,
Eugene.
On Fri, Nov 2, 2012 at 10:44 AM, Youcef Laribi <Youcef.Laribi at eu.citrix.com<mailto:Youcef.Laribi at eu.citrix.com>> wrote:
Eugene, Salvatore,

In order to clarify the terminology in our meetings and not get confused, I'm trying to draw a picture that represents how Quantum is organized today (mostly for myself). I have uploaded an attempt here:
http://wiki.openstack.org/Quantum/LBaaS?action=AttachFile&do=view&target=Quantum+Internal+components.png

Can you please check it for accuracy since you are familiar with the code? Once we agree and understand this picture, we can more easily discuss what needs to be changed in Quantum to accommodate LBaaS.

Youcef

From: Eugene Nikanorov [mailto:enikanorov at mirantis.com<mailto:enikanorov at mirantis.com>]
Sent: Wednesday, October 31, 2012 6:32 AM
To: openstack-dev at lists.openstack.org<mailto:openstack-dev at lists.openstack.org>
Subject: [openstack-dev] [Quantum][LBaaS] Advanced Services Insertion

Hi Salvatore,

I'd like to give some feedback/questions based on yesterday's meeting discussion and your renewed http://wiki.openstack.org/Quantum/ServiceInsertion page.

First of all, I think it's worth to fix the terminology just to avoid any confusion:

- extension (API extension) - set of REST calls
- plugin - code that implements certain API, works with quantum database, pushes calls to agents
- core plugin - code that implements core API (networks, subnets, ports, L3)
- agent - listens to commands from plugin, applies configuration to particular device type, ex: ovs agent, L3 agent
- driver - code that applies conf to particular device type. That is just another layer needed to support different device types. Example: Loadbalancing agent may have several drivers to talk to different LB devices.

Some thoughts on the Service Insertion proposal:

1. It seems that multiplugin approach is the right way to move further compared to "mixin" approach where we inject and modify code of the core plugin.
This will preserve plugin independency while require some changes to infrastructure (plugin loading, extension management).

2. Having several implementations of the same service type.
If all services of the certain type implement the same calls, then something should allow to route the call to particular plugin.
The options include:
  1)  passing particular service impl as a url parameter
  2)  having a prefix in uri for certain svc type: /lb_svc/lbaas_impl1/call.json, /lb_svc/lbaas_impl2/call.json
  3)  having (tenant, service implementation) assosiation in DB that will allow to route a call automatically. But this makes 1 to 1 relation, e.g. tenant will have only 1 impl of service available

My preference is (2): first of all, it "splits" whole API between core API and Adv Svc API, and also does so for different service type implementations.
Although URIs may not be so short as we want them, that could prevent from naming collisions between different service types.

3. Service Insertion:
I was thinking about routed/floating-mode insertion and there is a certain thing I don't understand: the workflow.
It seems that the whole thing is somehow close to what we used to call "device management" in mirantis implementaion of lbaas, but it doesn't look like solving all device management tasks.

So in our implementation of LBaaS the workflow was as following:
1) admin creates the device. Essentially it's just an instruction to LBaaS of where is the device (it's address), which type is it and credentials to manage it.
2) tenant creates VIP. During this operation LBaaS chooses the most appropriate device from the list of available and makes appropriate device configuration

If we're talking about workflow within Quantum it could look like following (scenario 1 - shared HW device):
1) admin creates the device. The same as in lbaas - address, type, credentials
2) tenant creates VIP: Quantum LBaaS plugin chooses the device, configures connectivity between the device and tenant network (possibly with l3 router configuration),
configures loadbalancer according to provided VIP parameters, possibly assigns floating IP from external network

If we're talking about private balancer with Quantum, then:
1) tenant creates the device. This could be a launch of VM with HA Proxy within tenant for instance.
2) tenant creates VIP: LBaaS configures loadbalancer according to provided VIP parameters, possibly assigns floating IP from external network. No other actions required

It would be great if you explain how service assignments for routers maps to device management scenarios and what exact workflow will be.

Thanks,
Eugene.

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