[openstack-dev] [Neutron] UniqueConstraint for name and tenant_id in security group

Maru Newby marun at redhat.com
Fri Dec 12 18:05:40 UTC 2014

On Dec 11, 2014, at 2:27 PM, Sean Dague <sean at dague.net> wrote:

> On 12/11/2014 04:16 PM, Jay Pipes wrote:
>> On 12/11/2014 04:07 PM, Vishvananda Ishaya wrote:
>>> On Dec 11, 2014, at 1:04 PM, Jay Pipes <jaypipes at gmail.com> wrote:
>>>> On 12/11/2014 04:01 PM, Vishvananda Ishaya wrote:
>>>>> On Dec 11, 2014, at 8:00 AM, Henry Gessau <gessau at cisco.com> wrote:
>>>>>> On Thu, Dec 11, 2014, Mark McClain <mark at mcclain.xyz> wrote:
>>>>>>>> On Dec 11, 2014, at 8:43 AM, Jay Pipes <jaypipes at gmail.com
>>>>>>>> <mailto:jaypipes at gmail.com>> wrote:
>>>>>>>> I'm generally in favor of making name attributes opaque, utf-8
>>>>>>>> strings that
>>>>>>>> are entirely user-defined and have no constraints on them. I
>>>>>>>> consider the
>>>>>>>> name to be just a tag that the user places on some resource. It
>>>>>>>> is the
>>>>>>>> resource's ID that is unique.
>>>>>>>> I do realize that Nova takes a different approach to *some*
>>>>>>>> resources,
>>>>>>>> including the security group name.
>>>>>>>> End of the day, it's probably just a personal preference whether
>>>>>>>> names
>>>>>>>> should be unique to a tenant/user or not.
>>>>>>>> Maru had asked me my opinion on whether names should be unique and I
>>>>>>>> answered my personal opinion that no, they should not be, and if
>>>>>>>> Neutron
>>>>>>>> needed to ensure that there was one and only one default security
>>>>>>>> group for
>>>>>>>> a tenant, that a way to accomplish such a thing in a race-free
>>>>>>>> way, without
>>>>>>>> use of SELECT FOR UPDATE, was to use the approach I put into the
>>>>>>>> pastebin on
>>>>>>>> the review above.
>>>>>>> I agree with Jay.  We should not care about how a user names the
>>>>>>> resource.
>>>>>>> There other ways to prevent this race and Jay’s suggestion is a
>>>>>>> good one.
>>>>>> However we should open a bug against Horizon because the user
>>>>>> experience there
>>>>>> is terrible with duplicate security group names.
>>>>> The reason security group names are unique is that the ec2 api
>>>>> supports source
>>>>> rule specifications by tenant_id (user_id in amazon) and name, so
>>>>> not enforcing
>>>>> uniqueness means that invocation in the ec2 api will either fail or be
>>>>> non-deterministic in some way.
>>>> So we should couple our API evolution to EC2 API then?
>>>> -jay
>>> No I was just pointing out the historical reason for uniqueness, and
>>> hopefully
>>> encouraging someone to find the best behavior for the ec2 api if we
>>> are going
>>> to keep the incompatibility there. Also I personally feel the ux is
>>> better
>>> with unique names, but it is only a slight preference.
>> Sorry for snapping, you made a fair point.
> Yeh, honestly, I agree with Vish. I do feel that the UX of that
> constraint is useful. Otherwise you get into having to show people UUIDs
> in a lot more places. While those are good for consistency, they are
> kind of terrible to show to people.

While there is a good case for the UX of unique names - it also makes orchestration via tools like puppet a heck of a lot simpler - the fact is that most OpenStack resources do not require unique names.  That being the case, why would we want security groups to deviate from this convention?


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