Open Stack

Hi,

I made some investigation on the topic[1] and see several issues on this
way.

1. Plugin's create_port() is wrapped up in top level transaction for
create floating ip case[2], so it becomes more complicated to do IPAM
calls outside main db transaction.

- for create floating ip case transaction is initialized on
create_floatingip level:
create_floatingip(l3_db)->create_port(plugin)->create_port(db_base)
So IPAM call should be added into create_floatingip to be outside db
transaction

- for usual port create transaction is initialized on plugin's
create_port level, and John's change[1] cover this case:
create_port(plugin)->create_port(db_base)

Create floating ip work-flow involves calling plugin's create_port,
so IPAM code inside of it should be executed only when it is not wrapped
into top level transaction.

2. It is opened question about error handling.
Should we use taskflow to manage IPAM calls to external systems?
Or simple exception based model is enough to handle rollback actions on
third party systems in case of failing main db transaction.

[1] https://review.openstack.org/#/c/172443/
[2] neutron/db/l3_db.py: line 905

Thanks,
Pavel

On 10.04.2015 21:04, openstack-dev-request at lists.openstack.org wrote:
> L3 Team,
> 
> I have put up a WIP [1] that provides an approach that shows the ML2 create_port method refactored to use the IPAM driver prior to initiating the database transaction. Details are in the commit message - this is really just intended to provide a strawman for discussion of the options. The actual refactor here is only about 40 lines of code.
> 
> [1] https://review.openstack.org/#/c/172443/
> 
> 
> Thanks,
> John