Re: [dpdk-dev] [PATCH 0/4 for 2.3] vhost-user live migration support

[Yuanhan Liu <yuanhan.liu@linux.intel.com>]

On Mon, Dec 14, 2015 at 12:46:57PM +0300, Pavel Fedin wrote:
>  Hello!
> 
> > > Host<------->openVSwitch<----------->guest
> > >       LOCAL               vhostuser
> > >
> > >  So, in order to migrate the guest, i simply replicated this setup on both hosts, with the
> > same IPs on host side. And on both hosts i set up the following ruleset for openvswitch:
> > 
> > Regarding to "with the same IPs on host side": do you mean that you
> > configured the same IP on two hosts in the intranet?
> 
>  No intranet. You can think of it as an isolated network between the host and guest, and that's all. I just assigned an IP to ovs' LOCAL interface on both hosts, and these ovs instances knew nothing about each other, neither they forwarded packets between each other. I didn't want to make things overcomplicated and decided not to mess with host's own connection to the intranet, just something that sits on the other side of vhost-user and replies to PINGs was perfectly OK for me.

Pavel,

It seems that we have exactly the same test environment set up: I have
one server (where I normally do vhost test there) and one desktop (my
dev box), 

On both hosts, there is an ovs bridge, with IP address 192.168.100.1
assigned manually. Later, I started a VM on the server, and manually
assigned IP to 192.168.100.10. I then run "ping 192.168.100.1" for
live migration testing.

The migration to my desktop somehow works (even though there are some
bugs in this patch set), however, I did see what Pavel saw: about 12
packets has been lost, which means about 12 seconds the network is not
working well.

Besides that, there was always an error message from the target host
after the migration:

    KVM: injection failed, MSI lost (Operation not permitted)

Firstly, I've very limited knowledge of OVS, therefore I'm not sure
this kind of live migration test env is setup rightly or not. I'd
appreciate if anyone could shine some lights on it. Anyway, I'm digging
the code to see if I can find something abnormal there.

> > I think this
> > does not matter if we are testing it functionally (whether live
> > migration could work), However I would still perfer to try ping
> > another host (say, host3) inside the intranet. What do you think?
> 
>  Yes, perhaps this would be better test, may be next time i'll do it.

Again, appreciate your testing!

> Anyway, IIRC, PATCH v2 is coming.

Hopefully, I could fix this gap this week and send out v2.

	--yliu