[openstack-dev] [Quantum][LBaaS] Advanced Services Insertion
Youcef Laribi
Youcef.Laribi at eu.citrix.com
Tue Nov 6 02:38:16 UTC 2012
Anand,
This gets us to the discussion of "service type" that Salvatore has explained in his document, which I think accommodates your scenario.
If a vendor's "adapter" ("driver") is able to express the type of load-balancing capabilities it is providing through the concept of ServiceDefinition data structures used in Salvatore's doc (each "ServiceDefinition" could simply be a shortcut for things like "deviceX-version1", "deviceX-version2", "deviceY", "hardware-lb", "software-lb", "very-fast-lb", etc.), and then the "ServiceDefinitions" from all vendors are organized into "ServiceTypes" by the LBaaS admin, then the same service type can have 2 or more "ServiceDefinitions" from the same vendor ("adapter") and/or from different vendors. ServiceDefinitions of the same "advanced service" (e.g. LB) in the same "service type" are considered inter-changeable.
We just need to define the way for an "adapter" to express its "ServiceDefinitions". This could be either a static metadata file that each "adapter" must have, or the "adapter" can respond to a call asking it to describe its "ServiceDefinitions". There would be a mapping between an "adapter" (provider ID ?) and all the "ServiceDefinitions" it provides. When the adapter is called to perform a task, the call should specify the "ServiceDefinition" ID being picked by the LBaaS plugin.
Say the admin defines a service-type called "Gold", and maps it for LB to either ServiceDefinition ("vendor1"/"deviceX-v1") or ServiceDefinition ("vendor2"/"deviceZ"), while she maps service-type "Silver" for LB to only ServiceDefinition ("vendor1"/deviceX-v2"), when the user wants to create a "vip" using the "Gold" service type, then LBaaS plugin would need to pick either "vendor1"/"device-Xv1" or "vendor2/deviceZ" to service this request, and would need to remember that "vip A" was created using "ServiceDefinition X" in its database.
Youcef
From: Palanisamy, Anand [mailto:apalanisamy at paypal.com]
Sent: Monday, November 05, 2012 5:23 PM
To: OpenStack Development Mailing List
Subject: Re: [openstack-dev] [Quantum][LBaaS] Advanced Services Insertion
Youcef/Salvatore,
I hope, the single advanced service (LBaaS) plug-in with multiple adapters or drivers will address the "support for multiple-versions of each vendor" as well. Also, it is the plug-ins responsibility to dispatch the API calls to right adapter with right version.
Please confirm.
I agree that let us postpone the extension attribute discussion to G2 or G3.
Thanks
Anand
From: Salvatore Orlando <sorlando at nicira.com<mailto:sorlando at nicira.com>>
Reply-To: OpenStack Development Mailing List <openstack-dev at lists.openstack.org<mailto:openstack-dev at lists.openstack.org>>
Date: Tue, 6 Nov 2012 02:08:55 +0100
To: OpenStack Development Mailing List <openstack-dev at lists.openstack.org<mailto:openstack-dev at lists.openstack.org>>
Subject: Re: [openstack-dev] [Quantum][LBaaS] Advanced Services Insertion
Seems we all agree about having adapters or drivers for various types of devices, and that there will be no need to have multiple, co-existing plugins.
I think Youcef's reference to anyAttribute was for allowing a way to expose device-specific features on the tenant API. When you support multiple drivers, this become a bit tricky as some drivers might support a particular feature, whereas some other drivers might not.
Ideally, I would still use the API extension mechanism to this aim, as I think it's feasible and it seems an architecturally clean way of dealing with this problem. API extensions can define new resources, new attributes on existing resources, or add actions to existing resources. However, Quantum's extension framework will need to be improved for dealing with extensions that might be supported only by a specific driver. Although some ideas on how to solve this problem have been published at: http://wiki.openstack.org/Quantum/ServiceInsertion, it is my opinion that support for driver-specific capabilities could be delayed to either Grizzly-2 or 3.
Salvatore
On 6 November 2012 01:02, Sachin Thakkar <sthakkar at vmware.com<mailto:sthakkar at vmware.com>> wrote:
Yes, I think having a vendor specific adapter is very much in the plan. It should remain extensible in this manner. As Youcef mentioned, I doubt it'll be XSDs since there isn't as much XML in the quantum project but the same model used for L2 should work.
Sachin
----- Original Message -----
From: "Youcef Laribi" <Youcef.Laribi at eu.citrix.com<mailto:Youcef.Laribi at eu.citrix.com>>
To: "OpenStack Development Mailing List" <openstack-dev at lists.openstack.org<mailto:openstack-dev at lists.openstack.org>>
Sent: Monday, November 5, 2012 1:48:15 PM
Subject: Re: [openstack-dev] [Quantum][LBaaS] Advanced Services Insertion
Hi Peter,
I think we all agree that the LBaaS APIs allows for extensions in line with other OpenStack APIs. As I said earlier the use of XSDs to generate the APIs is not an established practice in OpenStack projects (and in Quantum), but we can certainly use XSDs to document the API if it helps. Vendor drivers should be able to support extensions. If the user wants to use a certain LBaaS extension and this extension is only implemented by some vendors drivers, then this could be used to select that vendor's implementation (using the "service type" mechanism described by Salvatore?).
Youcef
From: Mellquist, Peter [mailto:peter.mellquist at hp.com<mailto:peter.mellquist at hp.com>]
Sent: Monday, November 5, 2012 1:16 PM
To: OpenStack Development Mailing List
Subject: Re: [openstack-dev] [Quantum][LBaaS] Advanced Services Insertion
Hi Youcef,
This sound good. One question, can the model be extended by a vendor specific adapter? ( In Atlas, you had the XSDs (schema ) allow <anyAttributes> which seemed to allow this )
Thanks
Peter.
From: Youcef Laribi [ mailto:Youcef.Laribi at eu.citrix.com<mailto:Youcef.Laribi at eu.citrix.com> ]
Sent: Monday, November 05, 2012 1:03 PM
To: OpenStack Development Mailing List
Subject: Re: [openstack-dev] [Quantum][LBaaS] Advanced Services Insertion
Returning to the LBaaS plugin design, my current assumption (and I want to check if this is shared) is that we don't want to have a separate LBaaS plugin for each vendor (even though this is of course possible). There is a core functionality in LBaaS that needs to be implemented anyway and therefore if we agree how this is done, it makes sense to have one piece (one plugin) doing this (like the eBay and Atlas services had). This piece (the LBaaS plugin) will for example maintain the LBaaS data model as defined by the API. Then there are the vendor-specific parts (the ones we called "adapters" in Atlas, others call them "drivers", etc.). And we would want to be able to have several of these vendor drivers loaded simultaneously in an LBaaS service.
Some of these drivers can also implement several "advanced services". So, a vendor's "driver" could implement more than one "advanced service" interface if it wants to (e.g. a firewall + lb) therefore interfacing with several Quantum plugins. I have a picture illustrating this setup ( http://wiki.openstack.org/Quantum/LBaaS?action=AttachFile&do=view&target=Quantum+LBaaS+plugin+with+providers.png ). Would love to hear your thoughts on the above.
Youcef
From: Salvatore Orlando [ mailto:sorlando at nicira.com<mailto:sorlando at nicira.com> ]
Sent: Monday, November 5, 2012 8:03 AM
To: OpenStack Development Mailing List
Subject: Re: [openstack-dev] [Quantum][LBaaS] Advanced Services Insertion
Hi Youcef,
sorry about the delay in my reply.
I think consensus about the right approach is starting to maturing. I totally agree with you on the need for having clear interfaces.
For the L3 functionality, at the summit we decided to regard it as "core". And indeed I already have a blueprint for moving the APIs from extensions to core.
So, technically speaking, L3 will become part of the core plugin.
However, as I also discussed on the wiki page, I'd like community input to understand how to deal with Floating IPs, which despite being part of the L3 extension kind of represent an "advanced" service.
Salvatore
On 2 November 2012 20:00, Youcef Laribi < Youcef.Laribi at eu.citrix.com<mailto:Youcef.Laribi at eu.citrix.com> > wrote:
Thanks Salvatore. I'm also in favor of loading several plugins and have clean interfaces between them.
Does this mean the L3 functionality will be factored out in its own plugin if we go with the "multiple plugins" approach, or will you keep it in the "core plugin" ?
Youcef
From: Salvatore Orlando [mailto: sorlando at nicira.com<mailto:sorlando at nicira.com> ]
Sent: Friday, November 2, 2012 10:28 AM
To: OpenStack Development Mailing List
Subject: Re: [openstack-dev] [Quantum][LBaaS] Advanced Services Insertion
Youcef,
The proposals you've described are exactly the ones being considered on the wiki page.
I am considering both at the moment, and I'm evaluating them along the following dimensions:
1) Flexibility (and the multiple plugins approach here is a winner, probably)
2) Impact on Quantum architecture (single plugin would be the one with the lowest impact)
3) Implementation effort (here I am still undecided, as the approach with a single plugin ends up moving the complexity from Quantum server to the plugin)
It seems we have not yet a clear decision, but several people from the community are advocating for clean, separate interfaces among plugins.
Another option we might consider is whether we start adopting 1 plugin per type of service (so 1 core plugin, 1 firewall plugin, 1 load balancing plugin), and update quantum to dispatch the call to the appropriate plugin.
On this single 'LB' plugin we can immediately start providing an OSS implementation, so that Quantum users will have the ability of testing the feature. Vendor-specific plugin might follow suit. What we will not have immediately (and I mean G-1 or G-2) is the ability of serving multiple providers at the same time, which is one of the fundamental requirements for LBaaS, but we can commit to add this capability by G-3.
Thanks,
Salvatore
On 2 November 2012 16:45, Youcef Laribi < Youcef.Laribi at eu.citrix.com<mailto:Youcef.Laribi at eu.citrix.com> > wrote:
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<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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