In the OVSSfcAgent migration to a L2 agent extension review[1], Igor
Duarte Cardoso noticed a difference on the OpenFlow versions between a
comment and actual code.
In current code [2], we have:
# We need to dump-groups according to group Id,
# which is a feature of OpenFlow1.5
full_args = ["ovs-ofctl", "-O openflow13", cmd, self.br_name

Indeed, only OpenFlow 1.5 and later support dumping a specific group
[3]. Earlier versions of OpenFlow always dump all groups.
So current code will return all groups:
$ sudo ovs-ofctl -O OpenFlow13 dump-groups br-int 1
OFPST_GROUP_DESC reply (OF1.3) (xid=0x2):
$ sudo ovs-ofctl -O OpenFlow15 dump-groups br-int 1
OFPST_GROUP_DESC reply (OF1.5) (xid=0x2):

This code behavior will not change in my extension rewrite, so this
will still have to be fixed. though I am not sure on the solution:
* We can use Openflow 1.5, but its support looks experimental? And
Neutron apparently only uses up to 1.4 (for OVS firewall extension)
* Method to dump a group can "grep" the group ID in the complete dump.
Not as efficient but works with OpenFlow 1.1+
* Use another system to load balance across the port pairs?

In gerrit, I kept it set to 1.5 (no impact for now as this is still
marked as WIP)


Bernard Cafarelli

OpenStack Development Mailing List (not for usage questions)

Reply via email to