Open Stack

Yes, maybe. I'm interested in a pluggable IPAM module that will allocate an IP address for a VM that depends on where that VM's host is‎ in the physical data center network. Is that similar to your requirement?

I don't yet know whether that might lead me to want to store additional data in the Neutron DB. My intuition though is that it shouldn't, and that any additional data or state that I need for this IPAM module should be stored separately from the Neutron DB.

Regards,
       Neil


From: Shraddha Pandhe
Sent: Friday, 6 November 2015 20:23
To: OpenStack Development Mailing List (not for usage questions)
Reply To: OpenStack Development Mailing List (not for usage questions)
Subject: Re: [openstack-dev] [Neutron][IPAM] Arbitrary JSON blobs in ipam db tables


Bumping this up :)


Folks, does anyone else have a similar requirement to ours? Are folks making scheduling decisions based on networking?



On Thu, Nov 5, 2015 at 12:24 PM, Shraddha Pandhe <spandhe.openstack at gmail.com<mailto:spandhe.openstack at gmail.com>> wrote:
Hi,

I agree with all of you about the REST Apis.

As I said before, I had to bring up the idea of JSON blob because based on previous discussions, it looked like neutron community was not willing to enhance the schemas for different ipam dbs. Entire rationale behind pluggable IPAM is to provide flexibility. So, community should be open to ideas for enhancing the schema to incorporate more information in the db tables. I would be extremely happy if use cases for different companies are considered and schema is enhanced to include specific columns in db  schemas instead of a column with random JSON blob.

Lets pick up subnets db table for example. We have some use cases where it would be great if following information is associated with the subnet db table

1. Rack switch info
2. Backplane info
3. DHCP ip helpers
4. Option to tag allocation pools inside subnets
5. Multiple gateway addresses

We also want to store some information about the backplanes locally, so a different table might be useful.

In a way, this information is not specific to our company. Its generic information which ought to go with the subnets. Different companies can use this information differently in their IPAM drivers. But, the information needs to be made available to justify the flexibility of ipam

In Yahoo! OpenStack is still not the source of truth for this kind of information and database limitation is one of the reasons. I would prefer to avoid having our own database to make sure that our use-cases are always shared with the community.








On Thu, Nov 5, 2015 at 9:37 AM, Kyle Mestery <mestery at mestery.com<mailto:mestery at mestery.com>> wrote:
On Thu, Nov 5, 2015 at 10:55 AM, Jay Pipes <jaypipes at gmail.com<mailto:jaypipes at gmail.com>> wrote:
On 11/04/2015 04:21 PM, Shraddha Pandhe wrote:
Hi Salvatore,

Thanks for the feedback. I agree with you that arbitrary JSON blobs will
make IPAM much more powerful. Some other projects already do things like
this.

:( Actually, though "powerful" it also leads to implementation details leaking directly out of the public REST API. I'm very negative on this and would prefer an actual codified REST API that can be relied on regardless of backend driver or implementation.

I agree with Jay here. We've had people propose similar things in Neutron before, and I've been against them. The entire point of the Neutron REST API is to not leak these details out. It dampens the strength of the logical model, and it tends to have users become reliant on backend implementations.


e.g. In Ironic, node has driver_info, which is JSON. it also has an
'extras' arbitrary JSON field. This allows us to put any information in
there that we think is important for us.

Yeah, and this is a bad thing, IMHO. Public REST APIs should be structured, not a Wild West free-for-all. The biggest problem with using free-form JSON blobs in RESTful APIs like this is that you throw away the ability to evolve the API in a structured, versioned way. Instead of evolving the API using microversions, instead every vendor just jams whatever they feel like into the JSON blob over time. There's no way for clients to know what the server will return at any given time.

Achieving consensus on a REST API that meets the needs of a variety of backend implementations is *hard work*, yes, but it's what we need to do if we are to have APIs that are viewed in the industry as stable, discoverable, and reliably useful.

++, this is the correct way forward.

Thanks,
Kyle


Best,
-jay

Best,
-jay

Hoping to get some positive feedback from API and DB lieutenants too.


On Wed, Nov 4, 2015 at 1:06 PM, Salvatore Orlando
<salv.orlando at gmail.com<mailto:salv.orlando at gmail.com> <mailto:salv.orlando at gmail.com<mailto:salv.orlando at gmail.com>>> wrote:

    Arbitrary blobs are a powerful tools to circumvent limitations of an
    API, as well as other constraints which might be imposed for
    versioning or portability purposes.
    The parameters that should end up in such blob are typically
    specific for the target IPAM driver (to an extent they might even
    identify a specific driver to use), and therefore an API consumer
    who knows what backend is performing IPAM can surely leverage it.

    Therefore this would make a lot of sense, assuming API portability
    and not leaking backend details are not a concern.
    The Neutron team API & DB lieutenants will be able to provide more
    input on this regard.

    In this case other approaches such as a vendor specific extension
    are not a solution - assuming your granularity level is the
    allocation pool; indeed allocation pools are not first-class neutron
    resources, and it is not therefore possible to have APIs which
    associate vendor specific properties to allocation pools.

    Salvatore

    On 4 November 2015 at 21:46, Shraddha Pandhe
    <spandhe.openstack at gmail.com<mailto:spandhe.openstack at gmail.com> <mailto:spandhe.openstack at gmail.com<mailto:spandhe.openstack at gmail.com>>>
    wrote:

        Hi folks,

        I have a small question/suggestion about IPAM.

        With IPAM, we are allowing users to have their own IPAM drivers
        so that they can manage IP allocation. The problem is, the new
        ipam tables in the database have the same columns as the old
        tables. So, as a user, if I want to have my own logic for ip
        allocation, I can't actually get any help from the database.
        Whereas, if we had an arbitrary json blob in the ipam tables, I
        could put any useful information/tags there, that can help me
        for allocation.

        Does this make sense?

        e.g. If I want to create multiple allocation pools in a subnet
        and use them for different purposes, I would need some sort of
        tag for each allocation pool for identification. Right now,
        there is no scope for doing something like that.

        Any thoughts? If there are any other way to solve the problem,
        please let me know




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