Comment 5 for bug 1596769

The user case came from the aodh zaqar driver. At that moment, user will get a 409 error when create a duplicated subscription, which will cause some unexpected errors at here https://github.com/openstack/aodh/blob/master/aodh/notifier/zaqar.py#L162

And when the zaqar driver was introduced at the first time, it doesn't support pre-signed URL. So that said, all the subscriptions have to be created in the driver, can't create in Zaqar. That's why I opened this bug.

But now, things changed. Firstly, Zaqar won't throw 409 if there is a duplicated subscription creation. And, Aodh's Zaqar driver can support pre-signed URL. So user can create subscriptions in Zaqar easily.

So, technically, we don't really have to support this now. But Flavio, would you mind explaining the design choice a bit more? Thanks.