[ovirt-users] macvlan + IPv6

[Jay Turner]

Closing the loop on this topic, while I still do not fully understand why
oVirt and libvirt are behaving differently with respect to MAC address
handling (specifically writing the VF MAC address back to the host),  that
is the source of my problems.  After disabling the security feature in the
i40e driver, and rebuilding, I no longer have issues passing traffic with
macvlan interfaces.

- jkt

On Tue, Feb 23, 2016 at 11:40 PM Edward Haas <edwardh at redhat.com> wrote:

>
>
> ----- Original Message -----
> | From: "Jay Turner" <jkt at iix.net>
> | To: users at ovirt.org
> | Sent: Tuesday, February 23, 2016 5:13:21 PM
> | Subject: Re: [ovirt-users] macvlan + IPv6
> |
> | As a follow-up to this, I made some headway in sorting out the source of
> the
> | issue, but hoping someone can give me a pointer to where this is
> happening
> | in the code, as well as some understanding for why.
> |
> | In oVirt, when I allocate a virtual function to a guest, a new MAC
> address is
> | generated for the VF (as it should be) from the MAC address pool in
> oVirt,
> | and then that MAC address is written to the VF on the hypervisor. Thus I
> end
> | up with something like:
> |
> | : ens11: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master i40e
> | state UP mode DEFAULT qlen 1000
> | link/ether 3c:fd:fe:9d:a1:38 brd ff:ff:ff:ff:ff:ff
> | vf 0 MAC 00:1a:4a:16:01:52, spoof checking on, link-state auto
> |
> | This *is not* how it happens under libvirt/virt-manager, however. When
> | allocating a VF to a guest under libvirt, a random MAC address is
> generated
> | and associated with the VF under the guest, but it is not written back to
> | the hypervisor, and is instead left as 00:00:00:00:00:00.
> |
> | I am pretty sure this writing of the MAC address at the hypervisor is
> causing
> | at least some of the issues I'm seeing, as with the Intel cards, that
> | prevents the guest from changing/adding a new MAC address, which is what
> | happens with the instantiation of a macvlan interface.
> |
> | So can anyone point me to where in the oVirt code this MAC address
> assignment
> | is occurring? Also curious why oVirt does this assignment, but libvirt
> does
> | not.
> |
> | Thanks!
> |
> | - jkt
> |
> | On Mon, Feb 22, 2016 at 2:51 PM Jay Turner < jkt at iix.net > wrote:
> |
> |
> |
> | Hoping someone can help with a problem my team is seeing under oVirt.
> |
> | We are making heavy use of macvlan interfaces (in VEPA mode) on-top of
> | virtual functions, under VMs being managed by oVirt. In this scenario
> IPv6
> | is not playing nicely, with no traffic going through, and messages about
> | neighbor solicitation. There are some pointers out there indicating the
> | issue stems from the fact IPv6 utilizing multicast for neighbor
> | solicitation, but nothing we have tried seems to work around this issue.
> |
> | The problem is made all the most bizarre by the fact that on the same
> | hardware libvirt + virt-manager works perfectly fine. I have looked at
> the
> | corresponding xml for the guests, and nothing seems to point to the
> | underlying cause for oVirt to fail, but libvirt to succeed.
> |
> | * Intel XL710 40G NICs (i40e/i40evf drivers)
> | * CentOS 7.1 (fully up-to-date)
> | * oVirt 3.6
> | * libvirt-1.2.17
> | * virt-manager-1.2.1-8
> |
> | Thanks for any pointers folks can provide.
> |
> | - jkt
> |
> | _______________________________________________
> | Users mailing list
> | Users at ovirt.org
> | http://lists.ovirt.org/mailman/listinfo/users
> |
>
> Could you please provide the dumpxml for both setups (oVirt and non-oVirt)?
> (sudo virsh -r dumpxml <domain>)
>
> Thanks,
> Edy.
>
>
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