[ovs-dev] Fedora 19 - gre broken/incompatible with openvswitch latest master?

Jesse Gross jesse at nicira.com
Tue Nov 19 01:33:31 UTC 2013


On Mon, Nov 18, 2013 at 4:54 PM, Nithin Nayak Sujir <nsujir at broadcom.com> wrote:
> I'm following these instructions to setup a gre tunnel between two VMs on
> two identical systems with Fedora 19.
> http://networkstatic.net/open-vswitch-gre-tunnel-configuration/
>
> With the fedora openvswitch module it works and I'm able to ping between VMs
> (I had to unload ip_gre and gre modules before loading openvswitch).
> However, if I compile and use the master branch, it doesn't work. The kernel
> is 3.11.8-200.fc19.x86_64.
>
>
> I have two identical systems with the latest openvswitch master branch
> running. Each has physical interface p4p1. They're connected back-to-back.
>
> Switch setup on system 1 is below. The other system is exactly the same
> except of course for remote_ip 173.16.50.100.
>
>     Bridge "br2"
>         Port "br2"
>             Interface "br2"
>                 type: internal
>         Port "tap0"
>             Interface "tap0"
>         Port "gre0"
>             Interface "gre0"
>                 type: gre
>                 options: {remote_ip="173.16.50.101"}
>     Bridge "br0"
>         Port "p4p1"
>             Interface "p4p1"
>         Port "br0"
>             Interface "br0"
>                 type: internal
>
>
> My VMs are connected to tap0 on each system. I have set ips 173.16.50.100
> and 173.16.50.101 on br0 of the systems and I can ping between them.
>
> However, I'm not able to ping vm-vm. Digging into this, I see it's because
> ARP is not resolved. On the destination system, I see the GRE encapsulated
> ARP packets being received at p4p1 and br0. But they don't get forwarded and
> delivered via br2 - tap0 to the VM and therefore get no reply.

There shouldn't be any differences in requirements. Are you sure that
the GRE module initialized correctly (look in dmesg for OVS-related
errors) and there are no iptables rules?



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