[ovs-dev] [PATCH] FAQ: Add an entry about reconfiguration

[YAMAMOTO Takashi]

It seems that the behaviour is not so intuitive.
cf. https://bugs.launchpad.net/neutron/+bug/1346861

Signed-off-by: YAMAMOTO Takashi <yamamoto at valinux.co.jp>
---
 FAQ | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/FAQ b/FAQ
index df5ac0e..21a04f3 100644
--- a/FAQ
+++ b/FAQ
@@ -731,6 +731,27 @@ A: It depends on mechanisms and configurations you want to use.
    you want to use ebtables rules.)  On NetBSD, you might want to
    consider using the bridge(4) with BRIDGE_IPF option.
 
+Q: It seems that Open vSwitch does nothing when I removed a port and
+   then immediately put it back.  For example, consider that p1 is
+   a port of type=internal:
+
+       ovs-vsctl del-port br0 p1 -- \
+           add-port br0 p1 -- \
+           set interface p1 type=internal
+
+A: It's expected that vSwitch "skips" intermediate steps especially
+   when it's in the middle of an OVSDB transaction.
+
+   If you want to make Open vSwitch actually destory and then re-create
+   the port for some side effects like resetting kernel setting for the
+   corresponding interface, you need to separate operations into multiple
+   OVSDB transactions.  In the following example, the first ovs-vsctl,
+   which doesn't have --no-wait, will block until Open vSwitch to reload
+   the new configuration and remove the port:
+
+       ovs-vsctl del-port br0 p1
+       ovs-vsctl add-port br0 p1 -- \
+           set interface p1 type=internal
 
 Quality of Service (QoS)
 ------------------------
-- 
1.9.4