[ovs-discuss] add-port return successfully but ofport is not available in 2 secs

Ben Pfaff blp at nicira.com
Tue Jul 1 17:48:19 UTC 2014


On Tue, Jul 01, 2014 at 01:14:16PM +0100, Joni Lee wrote:
> We seem to face a concurrent issue between 2 processes: "add-br" and "find Interface" as follows
> 
> 1. A "l3 agent" process added a port q-router to a bridge (br-int) by calling "ovs-vsctl?add-port"?and the command returned successfully:
> 
> Jun 30 07:30:13 neutron1 ovs-vsctl: 00001|vsctl|INFO|Called as /usr/bin/ovs-vsctl -- --may-exist add-port br-int qr-3cc2ad9c-a3 -- set Interface qr-3cc2ad9c-a3 type=internal -- set Interface qr-3cc2ad9c-a3 external-ids:iface-id=3cc2ad9c-a3a5-4bd0-b5d9-bbb12ea8a4b0 -- set Interface qr-3cc2ad9c-a3 external-ids:iface-status=active -- set Interface qr-3cc2ad9c-a3 external-ids:attached-mac=fa:16:3e:47:24:0c
> 
> 2. On the other hand, after 2 secs, another "ovs agent" process finds the interface, but ofport is empty:
> 
> $ ovs-vsctl -- --columns=external_ids,name,ofport find Interface external_ids:iface-id=3cc2ad9c-a3a5-4bd0-b5d9-bbb12ea8a4b0
> external_ids ? ? ? ?: {attached-mac="fa:16:3e:47:24:0c", iface-id="3cc2ad9c-a3a5-4bd0-b5d9-bbb12ea8a4b0", iface-status=active}
> name ? ? ? ? ? ? ? ? ?: "qr-3cc2ad9c-a3"
> ofport ? ? ? ? ? ? ? ? :?[] ? ?<<<<<< empty set
> 
> ofport?the empty set?means that the interface hasn't been created yet,?even the command "add-br" returned successfully???
> 
> 3. After some more seconds,?We checked and see that "ofport" is available.
> 
> Any ideas which causes the latency of "add-br" and how to improve it?

ovs-vsctl, without the --no-wait option, should only exit after the
reconfiguration is complete, so the behavior that you report under
point 2 is unexpected.

I would start by looking in the ovs-vswitchd log to see if it's
reporting some problem that quickly resolves.

If not, then I would look in the ovsdb log (with "ovsdb-tool -mm
show-log") to check out the sequence of database transactions.



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