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On 08/25/2016 03:49 PM, Vasiliy Tolstov
wrote:
25 Авг 2016 г. 21:38 пользователь "Laine Stump" <laine@xxxxxxxxx>
написал:
>
> On 08/25/2016 02:19 PM, Vasiliy Tolstov wrote:
>>
>> 25 Авг 2016 г. 19:18 пользователь "Laine Stump" <laine@xxxxxxxxx>
написал:
>> >
>> > On 08/25/2016 05:42 AM, Vasiliy Tolstov wrote:
>> >>
>> >> 25 Авг 2016 г. 12:34 пользователь Vasiliy
Tolstov <v.tolstov@xxxxxxxxx>
написал:
>> >> >
>> >> > 25 Авг 2016 г. 8:58 пользователь "Laine
Stump" <laine@xxxxxxxxx> написал:
>> >> > >
>> >> > > The linkstate setting of an
<interface> is only meant to change the
>> >> > > online status reported to the guest
system by the emulated network
>> >> > > device driver in qemu,
>> >> >
>> >> I need to set host side status of interface.
Without this live migration with dinamic routing software (ospf
with quagga or bird) bring packet drops. Because on dest
interface in up state and kernel try to forward packets to it,
but guest CPU is not running.
>> >
>> >
>> > That shouldn't be a problem, since the IPInfo
isn't added to the tap device until immediately before the guest
CPU is started on the destination (that's the purpose of
qemuInterfaceStartDevice()).
>> >
>> >
>> >
>> >> Also host side status needed for easy
blackhole traffic to guest ip.
>> >
>> >
>> > Is this something you need to do while the guest
is already running? If not, then I think we don't need anything
extra.
>> >
>> >
>> >
>> >> May be create inside the source link state
attribute for host side link status? So it consistent with ip
and route elements?
>> >
>> >
>> > If necessary, that might be the right solution,
although I still think it's better to not set the tap device
offline, in case it's connected to a bridge - we wouldn't want
to trigger an STP forward delay. Maybe just delete (and later
re-add) the IPInfo would be less disruptive? (Or it might be
*more* disruptive, we'd have to try both).
>> >
>> >
>> Thanks for info.
>> Why not add ability to specify device state from host
side? If attribute is empty think that device is up. This is
reasonable default. I'm use link status when vm running, for
example if we have ddos - I down tap and via ospf route deleted
and traffic blackholed.
>
>
> Yeah, I can see the utility of that. And as long as the
default is up, then nobody is surprised by the results.
>
> So what we're talking about is a new subelement of
<source> for any tap-based interface type (at least):
>
> <interface type='ethernet|bridge|network'>
> <source>
> <link state='down'/>
> </source>
>
> Since it also needs to be supported for
qemuDomainChangeNet(), I'm doubtful this can be done prior to
the freeze tonight or early tomorrow, since DV is in China)
though. So will it be okay to have the patches I've made in this
release (which should handle proper operation for everything
except the "need to modify the state while the guest is running"
case)? I don't think any of that will need to be *un*done to
support this new attribute, and it would be nice to have
something in the next release that works at least in the default
situation...
Thanks, I'm happy with this.
Can you ACK Patches 2/3 and 3/3?
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