[ovs-dev] [PATCH v3] ovn: Support a new Logical_Switch_Port.type - 'external'

Han Zhou zhouhan at gmail.com
Tue Dec 18 20:21:14 UTC 2018


Hi Numan, I haven't finished reviewing the whole patch yet, but I have some
questions inlined.


> +
> +    <ul>
> +      <li>
> +        <p>
> +          For each router port IP address <code>A</code> which belongs
to the
> +          logical switch, A priority-100 flow is added which matches
> +          <code>REGBIT_EXT_PORT_NOT_RESIDENT &amp;&amp; arp.tpa ==
<var>A</var>
> +          &amp;&amp; arp.op == 1</code> (ARP request to the router
> +          IP) with the action to <code>drop</code> the packet.
> +        </p>
> +
> +        <p>
> +          These flows guarantees that the ARP/NS request to the router IP
> +          address from the external ports is responded by only the
chassis
> +          which has claimed these external ports. All the other chassis,
> +          drops these packets.
> +        </p>

Could you explain more about how this solves
https://bugzilla.redhat.com/show_bug.cgi?id=1613384
For my understanding, the logical router port MAC would still flap on the
physical switch ports, if there are multiple external ports and their
"requested-chassis" are set to different chassis. Or does this suggest
specifying a single chassis as "requested-chassis" for all external-ports?


> diff --git a/ovn/ovn-architecture.7.xml b/ovn/ovn-architecture.7.xml
> index 3936e6016..37b97a0d9 100644
> --- a/ovn/ovn-architecture.7.xml
> +++ b/ovn/ovn-architecture.7.xml
> @@ -1678,6 +1678,72 @@
>      </li>
>    </ol>
>
> +  <h2>Native OVN services for external logical ports</h2>
> +
> +  <p>
> +    To support OVN native services (like DHCP/IPv6 RA/DNS lookup) to the
> +    cloud resources which are external, OVN supports
<code>external</code>
> +    logical ports.
> +  </p>
> +
> +  <p>
> +    Below are some of the use cases where <code>external</code> ports
can be
> +    used.
> +  </p>
> +
> +  <ul>
> +    <li>
> +      VMs connected to SR-IOV nics - Traffic from these VMs by passes the
> +      kernel stack and local <code>ovn-controller</code> do not bind
these
> +      ports and cannot serve the native services.
> +    </li>

Would the broadcast traffic (e.g. DHCP discover) sent out from SR-IOV come
back to the local host? Is it free to select either the local host or any
other hosts as the "requested-chassis"? Or does this suggest that we have
to use a different chassis other than the local host as the
"requested-chassis"?

I will review in more detail later.

Thanks,
Han


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