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Hi Youcef,

Please see my comments inline.

On Wed, Nov 28, 2012 at 2:14 AM, Youcef Laribi
<Youcef.Laribi at eu.citrix.com>wrote:

> Changing the subject line (was: Progress on lbaas-plugin-api-crud)…****
>
> ** **
>
> Hi Eugene,****
>
> ** **
>
> Let’s make sure we agree on the assumptions:****
>
> ** **
>
> **-          **LBaaS Plugin has a set of drivers (vendor-specific).
>  Drivers run in the LBaaS agent process.
>
Agreed.

> **-          **Each driver (provider in Salvatore’s terminology) is
> registered against a service type (yes, service type can include LB
> drivers, firewall drivers, etc.).
>
Agreed.

> **-          **There can be several LBaaS drivers registered against the
> same service type (e.g. “high-performance LB” service type).
>
That probably needs to be clarified in more detail, but it does make sense.
As far as I understand there is exactly 1 driver per service type, but
there could be several service types referencing the same driver (like you
mentioned, "high-perf-lb", "low-cost-lb", etc)


> If these assumptions are incorrect or need to be clarified further, let’s
> start by doing this first J****
>
> ** **
>
> Now, let’s imagine we have a component in the system whose job is to pick
> a driver/provider (device type) and a device
>
(device id) given a certain service type. We will call this component the
> “placement component” (it’s not necessarily a  separate process like the
> scheduler, and can be part of the plugin, the agent or the driver, it
> doesn’t matter for this discussion at this stage).
>
I'd still prefer to call it a scheduler even though it will be a part of
our plugin or separate component.

> ****
>
> ** **
>
> The Placement Component needs to choose a device that can load-balance
> traffic coming from network A (where the VIP is) to VMs residing on Network
> B (pool’s network). In order to do this, the Placement Component needs to
> be aware of the capabilities of each driver/provider and can follow a
> certain strategy of device allocation that might take into account some of
> the following constraints. ****
>
> ** **
>
>   - Some device types are physical appliances, others are virtual
> appliances running on Nova. The driver might prefer one or the other if
> both satisfy the service type.
>
Agreed.


>   - Some device types have a fixed number of devices (e.g. physical
> appliances), while other devices can be created at will whenever needed
> (e.g. HA-Proxy VMs).
>
Agreed.


>   - Some device types can host a high number of VIPs, others can host a
> smaller number.
>
Agreed. Typically such factors are accounted during scheduling process.

****
>
> ** **
>
>   - Given a choice between multiple device types that satisfy the same
> service type, preference could be given to a device that is already wired
> to network A and network B.
>
Not sure that this is necessary, but that could be an option.


> ****
>
>                 ****
>
>   - Given a choice between several equivalent devices (possibly of
> different device types), the least loaded one is chosen.****
>
>                 ****
>
>   - A placement policy could be to group all VIPs belonging to the same
> tenant on the same device whenever possible.****
>
>   ****
>
>   - A placement policy could be to group all VIPs belonging to the same
> network on the same device.****
>
> ** **
>
> All these are legitimate placement strategies/algorithms, and our
> placement component might be very basic or very sophisticated, but we can
> hide this from the rest of the system.
>
Nova has different scheduling drivers for this. We can use same approach as
well.

Now let's assume that Placement component working through some combination
> of these rules, has finally chosen a driver/provider (e.g. HA-Proxy) and a
> specific device (HA-Proxy device 1) or it decided to create a new device in
> a driver (spawned new HA-Proxy VM, which is now HA-Proxy device 2). Now it
> needs to wire the chosen device to Quantum Network A and Network B (if it's
> not already wired to these networks).  This requires the Placement
> Component to call Quantum to do the wiring (we need to figure out the
> interface between the 2). If the device is a Nova VM, then this is easy as
> it's done like for any other VM. If the device is physical then this
> depends on the L2 switch technology used in the Quantum service (VLAN,
> Linux-Bridge, etc.): the physical device (or a proxy of it) needs to run a
> Quantum L2 agent in order to wire the device correctly.
>
Agreed.

> ****
>
> ** **
>
> After all this is done, the device is ready to be configured with a VIP.
> The Placement Component can return the driver, device_id (and possibly
> other config data, like the address chosen for the VIP) to the LBaaS
> plugin, which proceeds to call the LBaaS agent in order to create the VIP
> on this device.
>
Agreed.

>
>
**
>
> If we can understand what are the tasks of the “placement component” and
> the interactions this component needs to have with other components, then
> it’s easier to figure out where it should run.
>
Recently we discussed an idea of separate plugin performing device
management and scheduling which will be a utility plugin for other service
plugins (not only lbaas).
I think we'll need at least some simple form of this component within our
lbaas efforts.

> ****
>
> ** **
>
> Youcef****
>
> ** **
>
> *From:* Eugene Nikanorov [mailto:enikanorov at mirantis.com]
> *Sent:* Monday, November 26, 2012 10:11 PM
> *To:* OpenStack Development Mailing List
> *Subject:* Re: [openstack-dev] [Quantum][LBaaS] Progress on
> lbaas-plugin-api-crud****
>
> ** **
>
> Hi Youcef,****
>
> ** **
>
> Driver doesn't "choose" device-specific info, driver is device-specific
> itself. ****
>
> When we send request to the agent, we need to specify which device to use.
> ****
>
> ** **
>
> So once the user have chosen device type via service_type on VIP creation,
> Quantum not only should associate VIP with device type, but also it should
> choose particular instance of that device type to deploy the VIP.****
>
> The process of choosing the instance is called scheduling. Unlike nova
> it's unreasonable for LBaaS to have separate scheduler service, thus it
> makes sense to have them built in the plugin.****
>
> I think we should not do this on agent since it doesn't have (and should
> not have) device database.****
>
> Not should it access quantum's database directly.****
>
> ** **
>
> So overall workflow will look like the following:****
>
> 1. Add a device (type, physical info) to device registry (this is a part
> of Provider API. Call to Quantum made by cloud provider in case of shared
> devices, or by tenant in case of private VM balancers) ****
>
> 2. Create a VIP, specifying service type (=device type) (call by tenant),
> ****
>
> 3. Choose device of specified type, associate the VIP with the device
> (made by Quantum/Plugin)****
>
> 4. Send message with (logical VIP info, device_type, physical device info)
> to LBaaS Agent (made by Quantum/Plugin)****
>
> 5. Communicate with particular device using driver according to
> device_type (LBaaS Agent)****
>
> ** **
>
> Any CRUD request processed by Agent should be supplied by device type and
> device parameters.****
>
> ** **
>
> You may think of alternative approach where device registry is held by the
> Agent or even driver, but this approach has the next disadvantages:****
>
> - Scheduling goes to Agent or Driver and thus Agent/Driver should store
> VIP-device association while VIP is a "foreign" object for the Agent/Driver.
> ****
>
> - If we go with multiple agents for large deployments, we'll need to sync
> their device databases****
>
> - Device locking will be complicated.****
>
> - If Agents will have non-intersecting sets of devices in their registries
> than scheduling will be complicated or not possible.****
>
> ** **
>
> Please share you thoughts on this.****
>
> ** **
>
> Thanks,****
>
> Eugene.****
>
> ** **
>
> ** **
>
> On Tue, Nov 27, 2012 at 3:38 AM, Youcef Laribi <
> Youcef.Laribi at eu.citrix.com> wrote:****
>
> Hi Eugene, Leon,****
>
>  ****
>
> Could we have the LBaaS plugin choose the “driver” based on service_type
> info, and then it’s the driver which choose the “device”? The driver can
> obviously have its own DB model where it stores device-specific info.****
>
>  ****
>
> Youcef****
>
>  ****
>
> *From:* Dan Wendlandt [mailto:dan at nicira.com]
> *Sent:* Monday, November 26, 2012 9:13 AM
> *To:* Leon Cui
> *Cc:* OpenStack Development Mailing List; Salvatore Orlando
> *Subject:* Re: [openstack-dev] 答复: 答复: 答复: 答复: 答复: Progress on
> lbaas-plugin-api-crud****
>
>  ****
>
>  ****
>
> On Mon, Nov 26, 2012 at 9:03 AM, Leon Cui <lcui at vmware.com> wrote:****
>
> Hi Eugene,****
>
> When did you change get merged into master? I did rebase on last Friday
> which supposed to be your latest code, but anyway I’m planning to do it
> again today. ****
>
>  ****
>
> Thanks for your reminder that I need to include device mgmt. into DB
> model.  Need to look at Salvatore’s change on ServiceType.****
>
>  ****
>
> It seems to me that each LB plugin should be able to define its own DB
> models for "device mgmt" (e.g., device address/credentials/etc.), as
> different plugins may have different strategies for how they manage
> devices.  The usual model is that plugins can define additional
> models/tables to manage entities that are specific to that plugin.  This is
> similar to how we didn't back the notion of a "vlan" into the DB model for
> "core plugins", since not all plugins will use vlans.  If you don't go down
> this route, you end up with a messy DB model as everyone keeps adding
> columns for items that only a particular plugin needs to track.  ****
>
>  ****
>
> Dan****
>
>  ****
>
>  ****
>
>  ****
>
> Thanks****
>
> Leon****
>
> *发件人**:* Eugene Nikanorov [mailto:enikanorov at mirantis.com]
> *发送时间:* 2012年11月26日 4:29****
>
>
> *收件人:* Leon Cui
> *抄送:* Ilya Shakhat; Sachin Thakkar; Oleg Bondarev; Salvatore Orlando; Dan
> Wendlandt****
>
> *主题:* Re: 答复: 答复: 答复: 答复: Progress on lbaas-plugin-api-crud****
>
>  ****
>
> Hi Leon,****
>
>  ****
>
> Thanks for sending me the patch.****
>
> I've looked at it briefly, there is one major thing I was able to identify:
> ****
>
> In order to couple things together (plugin, agent, drivers), we need to
> add device management at least to DB model.****
>
> In particular, each vip should have a reference to the device (which has a
> type and address/credentials). ****
>
> This information is passed in each agent notification message.****
>
> This part is missing in current design blueprints but i think we need to
> add it before we put the code on review.****
>
> Probably it will also depend on Salvatore's ServiceTypes part.****
>
>  ****
>
> Also I see that your patch is based on some of my outdated patches. ****
>
> My code was recently merged into the master so you can rebase on master
> using only Oleg's patch.****
>
>  ****
>
> Thanks,****
>
> Eugene.****
>
> On Fri, Nov 23, 2012 at 2:40 PM, Leon Cui <lcui at vmware.com> wrote:****
>
> Hi Eugene,****
>
> I’m still waiting for approval as openstack contributor.  For now I simply
> attached the patch file that you might want to take a look first.  Once I
> got the approval, I’ll try to post the view asap.****
>
>  ****
>
> Thanks****
>
> Leon****
>
> *发件人**:* Eugene Nikanorov [mailto:enikanorov at mirantis.com]
> *发送时间:* 2012年11月20日 22:57
> *收件人:* Leon Cui
> *抄送:* Ilya Shakhat; Sachin Thakkar; Oleg Bondarev; Salvatore Orlando; Dan
> Wendlandt
> *主题:* Re: 答复: 答复: 答复: Progress on lbaas-plugin-api-crud****
>
>  ****
>
> Leon,****
>
>  ****
>
> I'll take agent and rpc parts.****
>
> I have registered
> https://blueprints.launchpad.net/quantum/+spec/lbaas-agent-and-rpc to
> track this.****
>
>  ****
>
> Thanks,****
>
> Eugene.****
>
> On Tue, Nov 20, 2012 at 2:16 PM, Leon Cui <lcui at vmware.com> wrote:****
>
> Hi Eugene,****
>
> Thanks for your suggestion.  It looks good to me.  I’ll work out the UT
> first, and then align the class model to the diagram as you suggested.****
>
>  ****
>
> Thanks****
>
> Leon****
>
> *发件人**:* Eugene Nikanorov [mailto:enikanorov at mirantis.com]
> *发送时间:* 2012年11月20日 17:32****
>
>
> *收件人:* Leon Cui
> *抄送:* Ilya Shakhat; Sachin Thakkar; Oleg Bondarev; Salvatore Orlando****
>
> *主题:* Re: 答复: 答复: Progress on lbaas-plugin-api-crud****
>
>  ****
>
> replying to all...****
>
>  ****
>
> Leon,****
>
>  ****
>
> I think tests/unit/test_db_plugin.py  is right code to refer when writing
> unit tests for db code. The only thing is that unit tests written
> in test_db_plugin.py are a bit generic, e.g. the backend plugin is
> specified in particular plugin's UTs which inherit
> from QuantumDbPluginV2TestCase. I think UTs for balancer plugin may be more
> specific, testing LoadbalancerPluginDb class.****
>
>  ****
>
> Since you need dababase utility methods from QuantumDbPluginV2 then
> it's LoadbalancerPluginDb which should inherit from such QuantumDBBase (or
> whatever you call it), so overall diagram will look like:****
>
>  ****
>
> ServicePluginBase****
>
>     |****
>
> LoadBalancerPluginBase ****
>
>     |****
>
>     |                                       QuantumDBBase ****
>
>     |                                            |****
>
> LoadBalancerPlugin  <---------- LoadBalancerPluginDb****
>
>  ****
>
> Thanks,****
>
> Eugene.****
>
>  ****
>
> On Tue, Nov 20, 2012 at 1:04 PM, Leon Cui <lcui at vmware.com> wrote:****
>
> Hi Eugene,****
>
> Thanks for your suggestion.  Please see my comments inline.****
>
>  ****
>
> One more question: I’m writing the unit test, mainly to verify the
> database functionalities for LB CRUD.  Do you think
> tests/unit/test_db_plugin.py is the right test code that I should refer
> to?  Any good suggestions on this front?****
>
>  ****
>
> Thanks****
>
> Leon****
>
> *发件人**:* Eugene Nikanorov [mailto:enikanorov at mirantis.com]
> *发送时间:* 2012年11月20日 16:44
> *收件人:* Leon Cui
> *抄送:* Ilya Shakhat; Sachin Thakkar; Oleg Bondarev; Salvatore Orlando
> *主题:* Re: 答复: Progress on lbaas-plugin-api-crud****
>
>  ****
>
> Hi Leon,****
>
>  ****
>
> A few thoughts on your diagram.****
>
>  ****
>
> Please consider the following:****
>
> 1) If you want something from QuantumDbPluginV2 and you feel it may be
> common plugin functionality - you need to extract it to a separate class,
> something like QuantumPluginBase, and inherit QuantumDBPluginV2 from this
> class, ServicePluginBase should inherit from that class as well.****
>
> [Leon] I need some dababase utility methods from QuantumDbPluginV2.
> Abstract to a separate class could be a good idea. But I’m not sure if it’s
> a good idea to let ServicePluginBase to inherit from this class.
> ServicePluginBase is an abstract class for service plugin service (quantum
> manager) to use. ****
>
>  ****
>
> 2) LoadBalancerPluginBase imho should inherit from ServicePluginBase****
>
> [Leon] Why it needs to inherit from ServicePluginBase?
> LoadBalancerPluginBase defines the loadbalancer extension APIs.  I think we
> just make sure LoadbalancerPlugin inherits from both classes as below:****
>
> ServicePluginBase    QuantumPluginDbBase   LoadbalancerPluginBase****
>
>        |                       |                      |****
>
>         ----------------------------------------------****
>
>                                |****
>
>                         LoadbalancerPlugin    ------ LoadbalancerPluginDb*
> ***
>
>               ****
>
> LoadbalancerPlugin will contain the LoadbalancerPluginDb instance for
> database access.****
>
>  ****
>
>  ****
>
> 3) Depending on what you need from QuantumDbPluginV2/QuantumPluginBase,
> this may lead to the following inheritance sequence:****
>
> QuantumPluginBase****
>
>     |****
>
> ServicePluginBase****
>
>     |****
>
> LoadBalancerPluginBase ****
>
>     |****
>
> LoadBalancerPluginDb****
>
>     |****
>
> LoadBalancerPlugin****
>
>  ****
>
> Also, I think that LoadBalancerPlugin should not
> inherit LoadBalancerPluginDb. ****
>
> Unlike core plugins where it could make sense, I'd prefer to
> see LoadBalancerPluginDb to be a part of LoadBalancerPlugin.****
>
> I mean LoadBalancerPlugin implements "has a" LoadBalancerPluginDb  instead
> of "is a" relation. ****
>
> The reason for this is that LoadBalancerPlugin provides CRUD
> implementation which doesn't directly map to DB operations implemented
> in LoadBalancerPluginDb. ****
>
> E.g. my idea is:****
>
> LoadBalancerPlugin - CRUD, validation, calling LoadBalancerPluginDb,
> sending/receiving messages to agent****
>
> LoadBalancerPluginDb - DB access.****
>
>  ****
>
> Thanks,****
>
> Eugene.****
>
>  ****
>
> On Tue, Nov 20, 2012 at 6:54 AM, Leon Cui <lcui at vmware.com> wrote:****
>
> Hi Ilya,****
>
> Right now I took Eugene’s change under review (
> https://review.openstack.org/#/c/15733/) and am developing the database
> access logic and plugin skeleton based on that service plugin mechanism. The
> class model is illustrated in the below diagram:****
>
> [image: ServicePluginBase (quantum.plugins.services.service_base)
> ,QuantumDbPluginV2 (quantum.db. db_base_plugin_v2),LoadBalancerPluginDb
> (quantum.plugins.services.loadbalancer.loadbalancer_db),LoadBalancerPluginBase
> (quantum.extensions.loadbalancer)]****
>
> [image: LoadBalancerPlugin
> (quantum.plugins.services.loadbalancer.loadbalancerPlugin)]****
>
>  ****
>
>  ****
>
>  ****
>
>  ****
>
>  ****
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>  ****
>
>  ****
>
>  ****
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>  ****
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>  ****
>
>  ****
>
>  ****
>
>  ****
>
>  ****
>
>  ****
>
>  ****
>
>  ****
>
>
> ****
>
> LoadBalancerPlugin module is the main body of loadbalancer plugin which
> inherits from multiple classes:****
>
> -          ServicePluginBase: defines the abstract methods that a service
> plugin should implemented.****
>
> -          QuantumDbPluginV2: contains a set of generic quantum database
> access methods. I’m not sure if we really want to inherit from this class
> but I’d like to leverage the methods defined in this class.****
>
> -          LoadBalancerPluginDb: This the main part I’m coding on which
> wrap the Lbaas database model and CRUD operation against the database.****
>
>  ****
>
> My thought is that LoadBalancerPlugin will control the LBaaS CRUD API
> flow. For instance, “create_vip” method should first validate the input,
> update the database, send message to the LbAgent over AMQP channel, than
> update the database by setting the status from PENDING_CREATE to ACTIVE.**
> **
>
>  ****
>
> I’m trying to write unit tests against the database access now which will
> take a while to complete. Meanwhile it would be great to have your help on
> coding the RPC interaction between plugin and agent.****
>
>  ****
>
> I don’t like blocking your part. What’s the best practice to collaborate
> with you on this? Maybe I can shelve my change to you somehow?****
>
>  ****
>
> Thanks****
>
> Leon****
>
> *发件人**:* Ilya Shakhat [mailto:ishakhat at mirantis.com]
> *发送时间:* 2012年11月19日 22:08
> *收件人:* Sachin Thakkar; Leon Cui
> *抄送:* Eugene Nikanorov; Oleg Bondarev
> *主题:* Progress on lbaas-plugin-api-crud****
>
>  ****
>
> Hi Sachin, Leo, ****
>
>  ****
>
> Recently there was a thread related to LBaaS architecture (
> http://lists.openstack.org/pipermail/openstack-dev/2012-November/002646.html).
> How good is it aligned with your implementation? Do you need help in
> coding? (we may take Agent part) ****
>
>  ****
>
> Thanks,****
>
> Ilya****
>
>  ****
>
>  ****
>
>  ****
>
>  ****
>
>
>
> ****
>
>  ****
>
> --
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Dan Wendlandt ****
>
> Nicira, Inc: www.nicira.com****
>
> twitter: danwendlandt
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~****
>
>  ****
>
>
> _______________________________________________
> OpenStack-dev mailing list
> OpenStack-dev at lists.openstack.org
> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev****
>
> ** **
>
> _______________________________________________
> OpenStack-dev mailing list
> OpenStack-dev at lists.openstack.org
> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>
>
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