Open Stack

>    o) An idea to fix:
>
>       1. Set "taas" stamp(*) to taas flows.
>       2. Modify the cleanup logic in ovs-agent not to delete entries
>          stamped as "taas".
>
>       * Maybe a static string.
>         If we need to use a string which generated dynamically
>         (e.g. uuid), API to interact with ovs-agent is required.
>

   Last week I proposed to set a static string (e.g. "taas") as cookie
   of flows created by taas agent.

   But I found that the value of a cookie should not be a string,
   but an integer.

   At line 187 in 
"neutron/neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py":
   self.agent_uuid_stamp = uuid.uuid4().int & UINT64_BITMASK

   In case of we set an integer value to cookie, coordination
   (reservation of range) is required to avoid conflict of cookies with
   other neutron sub-projects.

   As an alternative (*** short term ***) solution, my idea is:
   Modify the clean up logic in ovs agent not to delete flows whose
   "cookie = 0x0".
   Because old flows created by ovs agent have an old stamp, "cookie =
   0x0" means it was created by other than ovs agent.

   # But, this idea has a disadvantage:
     If there are flows which have been created by older version of ovs
     agent, they can not be cleaned.

---
  Soichi Shigeta