allow_overlapping_ips=False fails for Concurrent requests

[Ritesh Shetty]

In my use case if i set allow_overlapping_ips=False i expect no duplicate CIDR's . This works fine. But under concurrent requests this fails. It creates duplicate CIDR's

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/34300

[Salvatore Orlando (salvatore-orlando)]

I have tried an approach based on db consistency (using a unique constraint between cidr and another 'dummy' attribute).
This won't work anyway, as it won't verify overlapping cidrs.

See here for the diff: http://paste.openstack.org/show/39432/

[Eugene Nikanorov (enikanorov)]

I think we need more input on this from submitter.
The code might have been changed during last year.
Marking as Incomplete, will reopen if new information appears.

[Ritesh Shetty (ritesh-s-shetty)]

What more information is needed?

[Cedric Brandily (cbrandily)]

This bug is > 365 days without activity. We are unsetting assignee and milestone and setting status to Incomplete in order to allow its expiry in 60 days.

If the bug is still valid, then update the bug status.

[Ihar Hrachyshka (ihar-hrachyshka)]

We validate the constraint in code (_validate_subnet_cidr) but if two transactions are started in parallel, and both try to allocate the same CIDR, then validation will succeed for both, and then they will be able to create those resources. Which would violate the expectation.

I presume the bug is real, so moving to another state.

[Nam (namnh)]

@Ihar Hrachyshka

Hi Ihar. I also report a bug [1] that it is similar to this bug. Anh I purposed a solution [2]. Could you review my solution and leave some comments, please.
BTW, Kevin suggest that I should create new table for this. However, the ideal is similer.

[1] https://launchpad.net/bugs/1532695
[2] https://review.openstack.org/#/c/267470/

[Launchpad Janitor (janitor)]

[Expired for neutron because there has been no activity for 60 days.]