Hi all,

In order to ease confusion I think I might create use case walk-throughs to 
show how the API would work. There's only been one week to work on this (minus 
other work) so I haven't had enough time to create them. I'll try to capture 
most of them in this form over the following week as I really think it will aid 
in understanding the document Brandon provided. Sometimes an illustration is 
easier to understand :). Anyways, just know that simplicity, flexibility and 
the ability to capture the majority of use cases was kept in mind when creating 
this proposal and I really think it will satisfy the requirements that everyone 
has put forth. See you all on IRC in a few hours!

Cheers,
--Jorge

From: Brandon Logan 
<brandon.lo...@rackspace.com<mailto:brandon.lo...@rackspace.com>>
Reply-To: "OpenStack Development Mailing List (not for usage questions)" 
<openstack-dev@lists.openstack.org<mailto:openstack-dev@lists.openstack.org>>
Date: Wednesday, April 16, 2014 9:17 PM
To: 
"openstack-dev@lists.openstack.org<mailto:openstack-dev@lists.openstack.org>" 
<openstack-dev@lists.openstack.org<mailto:openstack-dev@lists.openstack.org>>
Subject: Re: [openstack-dev] [Neutron][LBaaS] Requirements and API revision 
progress

Stephen,
Commenting in line below

On 04/16/2014 07:56 PM, Stephen Balukoff wrote:
Hi y'all!

This is actually a pretty good start for a revision of the Neutron LBaaS API.

My feedback on your proposed API v2.0 is actually pretty close to Eugene's, 
with a couple additions:

You say 'only one port and protocol per load balancer', yet I don't know how 
this works. Could you define what a 'load balancer' is in this case?  (port and 
protocol are attributes that I would associate with a TCP or UDP listener of 
some kind.)  Are you using 'load balancer' to mean 'listener' in this case 
(contrary to previous discussion of this on this list and the one defined here 
https://wiki.openstack.org/wiki/Neutron/LBaaS/Glossary#Loadbalancer )?

Yes, it could be considered as a Listener according to that documentation.  The 
way to have a "listener" using the same VIP but listen on two different ports 
is something we call VIP sharing.  You would assign a VIP to one load balancer 
that uses one port, and then assign that same VIP to another load balancer but 
that load balancer is using a different port than the first one.  How the 
backend implements it is an implementation detail (redudant, I know).  In the 
case of HaProxy it would just add the second port to the same config that the 
first load balancer was using.  In other drivers it might be different.


As pointed out, one pool per load balancer breaks any L7 switching 
functionality. SSL and L7 were the two major features that spawned this whole 
discussion about LBaaS a couple months ago, so any solution we propose should 
probably have these features.
Yes we agree one pool per load balancer breaks L7 switching functionality.  
However, as I told Eugene, we also came up with a "content_switching" object 
that would be a part of the load balancer root object.  In that object it does 
define multiple pools and rules.  The details of the pools and rules may indeed 
need some tweaking, but that doesn't mean this solution breaks the L7 switching 
requirement.

As for SSL, this absolutely allows SSL.  Using the common use case for SSL 
Termination:
1. Create an HTTP load balancer listening on port 80.
2. Create an HTTPS load balancer listening on port 443 sharing the same VIP and 
pool as the first load balancer.  Also, add an SSL Termination/SSL Decryption 
object to this 2nd load balancer.

We did not say much about the SSL Termination/SSL Decryption object because we 
wanted to make sure it was able to meet other requirements before we started to 
discuss that.

Context switching is the *only* reason to have multiple pools per load 
balancer... and I really just don't understand where the "consistency" argument 
between having "a pool" vs. "pools." I don't understand why one would think 
having multiple pools for a load balancer (that doesn't need them) would be a 
desired way to handle this "inconsistency" problem. Anyway... There's been 
discussion of this previously here: 
https://wiki.openstack.org/wiki/Neutron/LBaaS/l7  ...and I think I can 
illustrate (via proposed API) a better way to do this...  (in a nutshell, you 
need to have an additional object which links listeners to pools via a policy 
or rule. API is going to need to have controls to modify these rules.)

I'm not sure I fully understand the requirements behind the "single API call" 
proposal for creating a LBaaS service instance (whatever that means). 
Therefore, for now, I'm going to withhold any judgement on this or anything 
attempting to meet this requirement. Where does this need come from, and what 
are people expecting to see for their "single API call"?
The "single API call" is something we do currently use.  One reason to have it 
is because it is easier to understand from a user standpoint that creating a 
fully provisioned load balancer is done in one step at the /loadbalancers 
resource instead of having to go to 3 or more additional resources to do this.  
Now, since 90% of users will most likely be using some kind of GUI to do this 
it might minimize the need for this, but we still feel that creating less 
confusion is best.

Another reason we prefer this is because we have experience in an API that does 
need to make many calls and steps before a load balancer is actually up and 
running.  Once the environment all of the load balancers lived in became more 
and more dense, the provisioning time increased by many folds.  Once we were 
able to use an API that used the same backend and environment but every step 
was done in one call, the provisioning time was cut down by a factor of 20.  
Now this may just be a fluke only we encounter but I don't see how having a 
single API create call hurts anything.  The CLI client can still only have 
options to create a load balancer in 3 or more steps.

I'd like to take a stab at revising this API to reflect both the terminology 
defined in the glossary here:  
https://wiki.openstack.org/wiki/Neutron/LBaaS/Glossary  as well as addressing 
features having to do with SSL, L7 and (if y'all will let me) HA. I would also 
work off the requirements documents here:
https://wiki.openstack.org/wiki/Neutron/LBaaS/requirements
Features wishlist here:
https://wiki.openstack.org/wiki/Neutron/LBaaS/Usecases
Moderated by the real-world feature usage here:
https://docs.google.com/spreadsheet/ccc?key=0Ar1FuMFYRhgadDVXZ25NM2NfbGtLTkR0TDFNUWJQUWc&usp=sharing
... to try to create an API which addresses as much of this as possible (with 
appropriate object model diagrams for reference), yet still has "sane defaults" 
for simple use cases.

As an aside, it seems everyone's number one feature request at this time is HA. 
(more so than SSL and L7, yo!)

Note that I certainly won't have this ready for tomorrow's meeting, but could 
probably have a draft to show y'all at next week's meeting if y'all think it 
would be helpful to produce such a thing. Anyway, we can discuss this at 
tomorrow's meeting...
Please take a stab at it, the more ideas we all see the better we can make the 
revised API.  We can incorporate all the good ideas into one great API.  At 
least that is the hope

Thanks,
Stephen




On Wed, Apr 16, 2014 at 4:17 PM, Carlos Garza 
<carlos.ga...@rackspace.com<mailto:carlos.ga...@rackspace.com>> wrote:

On Apr 16, 2014, at 4:31 PM, Eugene Nikanorov 
<enikano...@mirantis.com<mailto:enikano...@mirantis.com>> wrote:

Hi folks,

I've briefly looked over the doc.

I think whole idea to base the API on Atlas misses the content switching use 
case, which is very important:
We need multiple pools within loadbalancer, and API doesn't seem to allow that.
If it would, then you'll face another problem: you need to reference those 
pools somehow inside the json you use in POST.
There are two options here: use names or IDs, both are putting constraints and 
create complexity for both user of such API and for the implementation.

That particular problem becomes worse when it comes to objects which might not 
have names while it's better to not provide ID in POST and rely on their random 
generation. E.g. when you need to create references between objects in json 
input - you'll need to create artificial attributes just for the parser to 
understand that such input means.

So that makes me think that right now a 'single-call API' is not flexible 
enough to comply with our requirements.

    We have demonstrated that you can create loadbalancers in separate 
transactions and in a single call fashion using both reference_ids to previous 
pools and as well as using a transient names to create objects in the same 
single call and reference them later on in other objects. The single call API 
is very flexible in that it allows you to create sub objects(We proposed 
transient ids to allow the user to avoid creating duplicate objects with 
different ids) on the fly as well as reference preexisting objects by id. The 
allowance for transient ids is adding flexibility to the api not taking away 
from it as you declared. I would like you to really be clear on what "our 
requirements"? What requirement is our single API call violating?

    We have thus far attempted to support a single call API that doesn't 
interfere with multiple smaller object creation calls. If we are just adding to 
the API  in a demonstrably workable fashion what is the real objection.


While I understand that it might be simpler to use such API for some cases, it 
makes complex configurations fall back to our existing approach which is 
creating configuration on per object basis.
While the problem with complex configurations is not sorted out, I'd prefer if 
we focus on existing 'object-oriented' approach.

    Your basically saying
P1: "The single API call proposal doesn't support *ALL* complex configurations"
P2: " if the single API proposal doesn't support *ALL* complex configurations 
the proposal should be rejected"

We have demonstrated that the proposed single API call can handle complex 
configurations via transient ids. So we already disagree with preposition 1.

We don't agree with preposition 2 either:
    We believe it is unfair to punish the API end user due to the religious 
belief that "The single API calls must support all possible configurations or 
you as the customer can't be allowed to use the single API call even for 
simpler configurations."

We want the single API call proposal to be as useful as possible so we are like 
wise looking at ways to have it solve ALL complex configurations and so far we 
feel transient IDs solve this problem already.

    Is the real objection that a single API call makes the implementation too 
complex? We are advocating that a single API makes it easier on the end user of 
the API and are of the impression that its better to have a complex 
implementation inside our neutron/lbaas code rather then passing that 
complexity down to the end user of the API.

    We don't object to multiple smaller object creation transactions we just 
want the addition of having single API call.


On the other hand, without single-call API the rest of proposal seems to be 
similar to approaches discussed in 
https://wiki.openstack.org/wiki/Neutron/LBaaS/LoadbalancerInstance/Discussion
    Since you linked the object model proposals could you also link the "rest 
of the proposals" or are you referring to our draft as "rest of proposal"?


Thanks,
Eugene.





On Thu, Apr 17, 2014 at 12:59 AM, Brandon Logan 
<brandon.lo...@rackspace.com<mailto:brandon.lo...@rackspace.com>> wrote:
Sorry about that.  It should be readable now.
________________________________
From: Eugene Nikanorov [enikano...@mirantis.com<mailto:enikano...@mirantis.com>]
Sent: Wednesday, April 16, 2014 3:51 PM

To: OpenStack Development Mailing List (not for usage questions)
Subject: Re: [openstack-dev] [Neutron][LBaaS] Requirements and API revision 
progress

Hi Brandon,

Seems that doc has not been made public, so please share.

Thanks,
Eugene.


On Thu, Apr 17, 2014 at 12:39 AM, Brandon Logan 
<brandon.lo...@rackspace.com<mailto:brandon.lo...@rackspace.com>> wrote:
Here is Jorge and team’s API proposal based on Atlas.  The document has some 
questions and answers about why decisions were made.  Feel free to open up a 
discussion about these questions and answers and really about anything.   This 
can be changed up to fit any flaws or use cases we missed that this would not 
support.

There is a CLI example at the bottom along with a possible L7 switching API 
model.

https://docs.google.com/document/d/1mTfkkdnPAd4tWOMZAdwHEx7IuFZDULjG9bTmWyXe-zo/edit

Thanks,
Brandon Logan

From: Eugene Nikanorov <enikano...@mirantis.com<mailto:enikano...@mirantis.com>>
Reply-To: 
"openstack-dev@lists.openstack.org<mailto:openstack-dev@lists.openstack.org>" 
<openstack-dev@lists.openstack.org<mailto:openstack-dev@lists.openstack.org>>
Date: Tuesday, April 15, 2014 at 7:00 AM
To: 
"openstack-dev@lists.openstack.org<mailto:openstack-dev@lists.openstack.org>" 
<openstack-dev@lists.openstack.org<mailto:openstack-dev@lists.openstack.org>>

Subject: Re: [openstack-dev] [Neutron][LBaaS] Requirements and API revision 
progress

Hi Stephen,

Thanks for a good summary. Some comments inline.


On Tue, Apr 15, 2014 at 5:20 AM, Stephen Balukoff 
<sbaluk...@bluebox.net<mailto:sbaluk...@bluebox.net>> wrote:

So! On this front:

1. Does is make sense to keep filling out use cases in Samuel's document above? 
I can think of several more use cases that our customers actually use on our 
current deployments which aren't considered in the 8 cases in Samuel's document 
thus far. Plus nobody has create any use cases from the cloud operator 
perspective yet.

I treat Sam's doc as a source of use cases to triage API proposals. If you 
think you have use cases that don't fit into existing API or into proposed API, 
they should certainly be brought to attention.


2. It looks like we've started to get real-world data on Load Balancer features 
in use in the real world. If you've not added your organization's data, please 
be sure to do so soon so we can make informed decisions about product 
direction. On this front, when will we be making these decisions?
I'd say we have two kinds of features - one kind is features that affect or 
even define the object model and API.
Other kind are features that are implementable within existing/proposed API or 
require slight changes/evolution.
First kind is the priority: while some of such features may or may not be 
implemented in some particular release, we need to implement proper 
infrastructure for them (API, obj model)

Oleg Bondarev (he's neutron core) and me are planning and mostly interested to 
work on implementing generic stuff like API/obj model and adopt haproxy driver 
to it. So our goal is to make implementation of particular features simpler for 
contributors and also make sure that proposed design fits in general lbaas 
architecture. I believe that everyone who wants to see certain feature may 
start working on it - propose design, participate in discussions and start 
actually writing the code.



3. Jorge-- I know an action item from the last meeting was to draft a revision 
of the API (probably starting from something similar to the Atlas API). Have 
you had a chance to get started on this, and are you open for collaboration on 
this document at this time? Alternatively, I'd be happy to take a stab at it 
this week (though I'm not very familiar with the Atlas API-- so my proposal 
might not look all that similar).

+1, i'd like to see something as well.


What format or template should we be following to create the API documentation? 
 (I see this here:  
http://docs.openstack.org/api/openstack-network/2.0/content/ch_preface.html  
but this seems like it might be a little heavy for an API draft that is likely 
to get altered significantly, especially given how this discussion has gone 
thus far. :/ )

Agree, that's too heavy for API sketch. I think a set of resources with some 
attributes plus a few cli calls is what could show the picture.

Thanks,
Eugene.

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--
Stephen Balukoff
Blue Box Group, LLC
(800)613-4305 x807



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