[RFC] dropping network hotplug support from network service

[Don Dutile]

On 06/21/2011 03:16 PM, Bill Nottingham wrote:
> Don Dutile (ddutile at redhat.com) said:
>>> Essentially, hot-adding a virtual device would not bring the device
>>> up automatically if you're using the old network service; you'd have
>>> to run 'ifup' by hand.
>>>
>> hot-adding a VF-nic to a Linux kvm guest brings up the hot-added (VF)
>> nic in the guest today.... am I missing what you mean?
>
> It depends on the network system in use - if NetworkManager is running,
> the guest will bring it up. If the old /etc/init.d/network service is
> running, it will only bring it up if there's an ifcfg file for that
> device (which is usually tied to the hardware address, but is sometimes
> just tied to the device name.)
>
>>>>> For #4, bringing up the device automatically can cause more issues
>>>>> than it solves. (We've seen this happen for vlans, for example.)
>>>> This is done all the time (on KVM hosts) to take down PF driver&   load
>>>> PF+VF drivers for SRIOV-capable devices.
>>>
>>> This would be a different device with a different hardware address,
>>> correct?
>>>
>> Nope; typically start up an SRIOV device in PF-only mode (igb, for
>> example), then do an rmmod igb; modprobe igb max_vfs=7;  same PF mac;
>> new VF mac's.
>>
>> and as VF's are added&  removed from guests, they may be removed&  added
>> back to host.
>
> The MAC addresses in the VF are still pseudo-random, correct?
>
depends on device vendor; some are based on PF value/prefix...

> Bill