[ovs-dev] [PATCH] ovn-northd: Support connecting multiple routers to a switch.
Guru Shetty
guru at ovn.org
Fri May 13 00:59:37 UTC 2016
>
>
> >>
> >> With respect to the other questions, I think its best approach would be
> to
> >> ask direct questions so those
> >> direct questions get answered.
> >>
> >> 1) With 1000 HVs, 1000 HVs/tenant, 1 distributed router per tenant, you
> >> choose the number of gateways/tenant:
> >>
> >> a) How many Transit LS distributed datapaths are expected in total ?
> >>
> >
> > One (i.e the same as the distributed router).
> >
>
>
> i.e.
> 1000 distributed routers => 1000 Transit LSs
>
Yes.
>
>
>
> >
> >
> >>
> >> b) How many Transit LS logical ports are needed at the HV level ?
> >>
> >> what I mean by that is lets say we have one additional logical port at
> >> northd level and 1000 HVs then if we need to download that port to 1000
> >> HVs, I consider that to be 1000 logical ports at the HV level because
> >> downloading and maintaining state across HVs at scale is more expensive
> >> than for a single hypervisor.
> >>
> >
> > 1000 additional ones. It is the same as your distributed logical switch
> or
> > logical router (this is the case even with the peer routers)
> >
>
> Did you mean 2000 including both ends of the Transit LS ?
>
No. One end is only on the physical gateway to act as a physical endpoint.
>
>
>
> >
> >
> >
> >>
> >> c) How many Transit LS arp resolve entries at the HV level ?
> >>
> >> what I mean by that is lets say we have one additional arp resolve flow
> at
> >> northd level and 1000 HVs then if we need to download that arp resolve
> >> flow
> >> to 1000 HVs, I consider that to be 1000 flows at the HV level because
> >> downloading and maintaining state across multiple HVs is more expensive
> >> that a single hypervisor.
> >>
> >
> > 2 ARP flows per transit LS * 1000 HVs.
> >
>
> oops; I underestimated by half
>
>
>
> > Do realize that a single bridge on a single hypervisor typically has
> flows
> > in the 100,000 range. Even a million is feasbile.
> >
>
> I know.
> I am thinking about the coordination across many HVs.
>
There is no co-ordination. HV just downloads from ovn-sb. This is
absolutely not different than any of the other distributed datapaths that
we have. If introduction of one additional datapath is a problem, then OVN
has a problem in general because it then simply means that it can only do
one DR per logical topology. A transit LS is much less resource intensive
(as it consumes just one additional port) than a DR connected to another DR
(not GR) as peers (in this case have 2 additional ports per DR and then
whatever additional switch ports that are connected to it).
If the larger concern is about having 1000 tenants, then we need to pass
more hints to ovn-controller about interconnections so that it only
programs things relevant to local VMs and containers which are limited by
the number of CPUs and Memory and is usually in the order of 10s.
>
>
>
> > Microsegmentation use cases has 10000 ACLs per logical switch. So that is
> > 10000 * 1000 for your case form single LS. So do you have some
> comparative
> > perspectives.
> >
> >
> >
> > dev mailing list
> >> dev at openvswitch.org
> >> http://openvswitch.org/mailman/listinfo/dev
> >>
> >
> >
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