[ovs-dev] [PATCH v2] FAQ: Add an entry about reconfiguration

[Ben Pfaff]

On Fri, Sep 19, 2014 at 11:18:49PM +0900, YAMAMOTO Takashi wrote:
> > On Fri, Sep 19, 2014 at 12:24:38AM +0900, YAMAMOTO Takashi wrote:
> >> 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>
> > 
> > I am not sure that I understand the bug report there.  It might be
> > reporting an actual bug in OVS.
> > 
> > The goal of ovs-vswitchd regarding the database is to make sure that
> > the state of the system is kept up-to-date with whatever is in the
> > database.  Maybe that bug report is saying, "If I have a port, and
> > then I del-port/add-port that in a single transaction, ovs-vswitchd
> > does not actually delete a port and then readd it at the datapath
> > level."  If it is saying that, then it is correct.  But that could
> > also happen if you use multiple transactions, because when it is busy
> > ovs-vswitchd might "miss" some of the intermediate transactions and
> > just implement the overall effect.
> 
> i referred the bug report because it seems that the author of
> original code mentioned in the bug expected it triggers re-creation
> of the port.
> 
> > 
> > The reason that two ovs-vsctl calls always deletes and readds a port
> > is a little different: the first ovs-vsctl waits for its transaction
> > to take effect before executing.  If you use "--no-wait", then you
> > just have two bare transactions and won't get the behavior of a
> > del-port followed by an add-port 100% of the time.
> 
> yes, it's my understanding.
> how about the following?

The new version is very good.

Acked-by: Ben Pfaff <blp at nicira.com>