Re: [openstack-dev] [neutron] - L3 flavors and issues with usecases for multiple L3 backends

2016-02-02 Thread rzang 
What advantage can we get from putting multiple drivers into one flavor over 
strictly limit one flavor one driver (or whatever it is called).


Thanks,
Rui


-- Original --
From:  "Kevin Benton";;
Send time: Wednesday, Feb 3, 2016 8:55 AM
To: "OpenStack Development Mailing List (not for usage 
questions)"; 

Subject:  Re: [openstack-dev] [neutron] - L3 flavors and issues with usecases 
for multiple L3 backends




Choosing from multiple drivers for the same flavor is scheduling. I didn't mean 
automatically selecting other flavors. 
 On Feb 2, 2016 17:53, "Eichberger, German"  wrote:
Not that you could call it scheduling. The intent was that the user could pick 
the best flavor for his task (e.g. a gold router as opposed to a silver one). 
The system then would ??schedule?? the driver configured for gold or silver. 
Rescheduling wasn??t really a consideration??
 
 German
 
 From: Doug Wiegley 
>
 Reply-To: "OpenStack Development Mailing List (not for usage questions)" 
>
 Date: Monday, February 1, 2016 at 8:17 PM
 To: "OpenStack Development Mailing List (not for usage questions)" 
>
 Subject: Re: [openstack-dev] [neutron] - L3 flavors and issues with use cases 
for multiple L3 backends
 
 Yes, scheduling was a big gnarly wart that was punted for the first pass. The 
intention was that any driver you put in a single flavor had equivalent 
capabilities/plumbed to the same networks/etc.
 
 doug
 
 
 On Feb 1, 2016, at 7:08 AM, Kevin Benton 
> wrote:
 
 
 Hi all,
 
 I've been working on an implementation of the multiple L3 backends RFE[1] 
using the flavor framework and I've run into some snags with the use-cases.[2]
 
 The first use cases are relatively straightforward where the user requests a 
specific flavor and that request gets dispatched to a driver associated with 
that flavor via a service profile. However, several of the use-cases are based 
around the idea that there is a single flavor with multiple drivers and a 
specific driver will need to be used depending on the placement of the router 
interfaces. i.e. a router cannot be bound to a driver until an interface is 
attached.
 
 This creates some painful coordination problems amongst drivers. For example, 
say the first two networks that a user attaches a router to can be reached by 
all drivers because they use overlays so the first driver chosen by the 
framework works  fine. Then the user connects to an external network which is 
only reachable by a different driver. Do we immediately reschedule the entire 
router at that point to the other driver and interrupt the traffic between the 
first two networks?
 
 Even if we are fine with a traffic interruption for rescheduling, what should 
we do when a failure occurs half way through switching over because the new 
driver fails to attach to one of the networks (or the old driver fails to 
detach from one)? It would seem the correct API experience would be switch 
everything back and then return a failure to the caller trying to add an 
interface. This is where things get messy.
 
 If there is a failure during the switch back, we now have a single router's 
resources smeared across two drivers. We can drop the router into the ERROR 
state and re-attempt the switch in a periodic task, or maybe just leave it 
broken.
 
 How should we handle this much orchestration? Should we pull in something like 
taskflow, or maybe defer that use case for now?
 
 What I want to avoid is what happened with ML2 where error handling is still a 
TODO in several cases. (e.g. Any post-commit update or delete failures in 
mechanism drivers will not trigger a revert in state.)
 
 1. https://bugs.launchpad.net/neutron/+bug/1461133
 2. 
https://etherpad.openstack.org/p/neutron-modular-l3-router-plugin-use-cases
 
 --
 Kevin Benton
 
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Re: [openstack-dev] [neutron] - L3 flavors and issues with usecasesfor multiple L3 backends

2016-02-02 Thread rzang 
Is it possible that the third router interface that the user wants to add will 
bind to a provider network that the chosen driver (for bare metal routers) can 
not access physically? Even though the chosen driver has the capability for 
that type of network? Is it a third dimension that needs to take into 
consideration besides flavors and capabilities? If this case is possible, it is 
a problem even we restrict all the drivers in the same flavor should have the 
same capability set. 




-- Original --
From:  "Kevin Benton";<blak...@gmail.com>;
Send time: Wednesday, Feb 3, 2016 9:43 AM
To: "OpenStack Development Mailing List (not for usage 
questions)"<openstack-dev@lists.openstack.org>; 

Subject:  Re: [openstack-dev] [neutron] - L3 flavors and issues with 
usecasesfor multiple L3 backends




So flavors are for routers with different behaviors that you want the user to 
be able to choose from (e.g. High performance, slow but free, packet logged, 
etc). Multiple drivers are for when you have multiple backends providing the 
same flavor (e.g. The high performance flavor has several drivers for various 
bare metal routers). 
 On Feb 2, 2016 18:22, "rzang" <rui.z...@foxmail.com> wrote:
What advantage can we get from putting multiple drivers into one flavor over 
strictly limit one flavor one driver (or whatever it is called).


Thanks,
Rui


-- Original --
From:  "Kevin Benton";<blak...@gmail.com>;
Send time: Wednesday, Feb 3, 2016 8:55 AM
To: "OpenStack Development Mailing List (not for usage 
questions)"<openstack-dev@lists.openstack.org>; 

Subject:  Re: [openstack-dev] [neutron] - L3 flavors and issues with usecases 
for multiple L3 backends




Choosing from multiple drivers for the same flavor is scheduling. I didn't mean 
automatically selecting other flavors. 
 On Feb 2, 2016 17:53, "Eichberger, German" <german.eichber...@hpe.com> wrote:
Not that you could call it scheduling. The intent was that the user could pick 
the best flavor for his task (e.g. a gold router as opposed to a silver one). 
The system then would ??schedule?? the driver configured for gold or silver. 
Rescheduling wasn??t really a consideration??
 
 German
 
 From: Doug Wiegley 
<doug...@parksidesoftware.com<mailto:doug...@parksidesoftware.com>>
 Reply-To: "OpenStack Development Mailing List (not for usage questions)" 
<openstack-dev@lists.openstack.org<mailto:openstack-dev@lists.openstack.org>>
 Date: Monday, February 1, 2016 at 8:17 PM
 To: "OpenStack Development Mailing List (not for usage questions)" 
<openstack-dev@lists.openstack.org<mailto:openstack-dev@lists.openstack.org>>
 Subject: Re: [openstack-dev] [neutron] - L3 flavors and issues with use cases 
for multiple L3 backends
 
 Yes, scheduling was a big gnarly wart that was punted for the first pass. The 
intention was that any driver you put in a single flavor had equivalent 
capabilities/plumbed to the same networks/etc.
 
 doug
 
 
 On Feb 1, 2016, at 7:08 AM, Kevin Benton 
<blak...@gmail.com<mailto:blak...@gmail.com>> wrote:
 
 
 Hi all,
 
 I've been working on an implementation of the multiple L3 backends RFE[1] 
using the flavor framework and I've run into some snags with the use-cases.[2]
 
 The first use cases are relatively straightforward where the user requests a 
specific flavor and that request gets dispatched to a driver associated with 
that flavor via a service profile. However, several of the use-cases are based 
around the idea that there is a single flavor with multiple drivers and a 
specific driver will need to be used depending on the placement of the router 
interfaces. i.e. a router cannot be bound to a driver until an interface is 
attached.
 
 This creates some painful coordination problems amongst drivers. For example, 
say the first two networks that a user attaches a router to can be reached by 
all drivers because they use overlays so the first driver chosen by the 
framework works  fine. Then the user connects to an external network which is 
only reachable by a different driver. Do we immediately reschedule the entire 
router at that point to the other driver and interrupt the traffic between the 
first two networks?
 
 Even if we are fine with a traffic interruption for rescheduling, what should 
we do when a failure occurs half way through switching over because the new 
driver fails to attach to one of the networks (or the old driver fails to 
detach from one)? It would seem the correct API experience would be switch 
everything back and then return a failure to the caller trying to add an 
interface. This is where things get messy.
 
 If there is a failure during the switch back, we now have a single router's 
resources smeared across two drivers. We can drop the router into the ERROR 
state and re-attempt

Re: [openstack-dev] [neutron] - L3 flavors and issues with use casesfor multiple L3 backends

2016-02-01 Thread rzang 
Hi Kevin,


I am probably talking about non-sense. But will we allow chaining routers with 
different flavors?
Taking it to the real world, if a router failed to attach to the external 
network in your description, it may probably need another gateway device which 
can do the bridging.


Otherwise, let's just leave the consequences to the user since there is no such 
auto fail-over in physical world that you plug-in an unsupported device and the 
whole system will magically auto-adjust and work.


Thanks,
Rui


-- Original --
From:  "Kevin Benton";;
Send time: Monday, Feb 1, 2016 10:08 PM
To: "openstack-dev"; 

Subject:  [openstack-dev] [neutron] - L3 flavors and issues with use casesfor 
multiple L3 backends




Hi all,
 
I've been working on an implementation of the multiple L3 backends RFE[1] using 
the flavor framework and I've run into some snags with the use-cases.[2]
 
The first use cases are relatively straightforward where the user requests a 
specific flavor and that request gets dispatched to a driver associated with 
that flavor via a service profile. However, several of the use-cases are based 
around the idea that there is a single flavor with multiple drivers and a 
specific driver will need to be used depending on the placement of the router 
interfaces. i.e. a router cannot be bound to a driver until an interface is 
attached. 
 
This creates some painful coordination problems amongst drivers. For example, 
say the first two networks that a user attaches a router to can be reached by 
all drivers because they use overlays so the first driver chosen by the 
framework works  fine. Then the user connects to an external network which is 
only reachable by a different driver. Do we immediately reschedule the entire 
router at that point to the other driver and interrupt the traffic between the 
first two networks? 
 
Even if we are fine with a traffic interruption for rescheduling, what should 
we do when a failure occurs half way through switching over because the new 
driver fails to attach to one of the networks (or the old driver fails to 
detach from one)? It would seem the correct API experience would be switch 
everything back and then return a failure to the caller trying to add an 
interface. This is where things get messy. 
 
If there is a failure during the switch back, we now have a single router's 
resources smeared across two drivers. We can drop the router into the ERROR 
state and re-attempt the switch in a periodic task, or maybe just leave it 
broken.
 
How should we handle this much orchestration? Should we pull in something like 
taskflow, or maybe defer that use case for now?
 
What I want to avoid is what happened with ML2 where error handling is still a 
TODO in several cases. (e.g. Any post-commit update or delete failures in 
mechanism drivers will not trigger a revert in state.) 
 
1. https://bugs.launchpad.net/neutron/+bug/1461133
 2. https://etherpad.openstack.org/p/neutron-modular-l3-router-plugin-use-cases
 
-- 
 Kevin Benton__
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