> On 19 Mar 2019, at 23:19, Michael S. Tsirkin <m...@redhat.com> wrote:
> On Tue, Mar 19, 2019 at 08:46:47AM -0700, Stephen Hemminger wrote:
>> On Tue, 19 Mar 2019 14:38:06 +0200
>> Liran Alon <liran.a...@oracle.com> wrote:
>>> b.3) cloud-init: If configured to perform network-configuration, it 
>>> attempts to configure all available netdevs. It should avoid however doing 
>>> so on net-failover slaves.
>>> (Microsoft has handled this by adding a mechanism in cloud-init to 
>>> blacklist a netdev from being configured in case it is owned by a specific 
>>> PCI driver. Specifically, they blacklist Mellanox VF driver. However, this 
>>> technique doesn’t work for the net-failover mechanism because both the 
>>> net-failover netdev and the virtio-net netdev are owned by the virtio-net 
>>> PCI driver).
>> Cloud-init should really just ignore all devices that have a master device.
>> That would have been more general, and safer for other use cases.
> Given lots of userspace doesn't do this, I wonder whether it would be
> safer to just somehow pretend to userspace that the slave links are
> down? And add a special attribute for the actual link state.

I think this may be problematic as it would also break legit use case of 
userspace attempt to set various config on VF slave.
In general, lying to userspace usually leads to problems. If we reach to a 
scenario where we try to avoid userspace issues generically and not
on a userspace component basis, I believe the right path should be to hide the 
net-failover slaves such that explicit action is required
to actually manipulate them (As described in blog-post). E.g. Automatically 
move net-failover slaves by kernel to a different netns.


> -- 

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