[libvirt] Network device abstraction aka virtual switch - V3

Laine Stump laine at laine.org
Sun Jul 3 23:50:09 UTC 2011

On 07/03/2011 03:42 PM, Christian Benvenuti (benve) wrote:
>> -----Original Message-----
>> From: sendmail [mailto:justsendmailnothingelse at gmail.com] On Behalf Of
>> Can this (the fact that the desired mode of operation will not allow for
>> sharing of interfaces) be determined absolutely from the existing config
>> information? In other words, is it safe to say that any time you have
>> the combination of "direct"/"private"/"802.1Qbh" that interfaces can't
>> be shared, but that for direct/private/<not-802.1Qbh>  they *can* be
>> shared?
>> I'm currently writing the code that picks an interface to use from the
>> pool; the information I have is roughly equivalent to what gets
>> configured for current libvirt domain interfaces:
>> |<interface type='direct'>
>> |<source dev='XYZ' mode='private'/>
>> |<virtualport type='802.1Qbh">
>> |<parameters
>> |</virtualport>
>> |</interface>
>> I want to avoid adding an explicit config item to the XML to
>> allow/prevent interface sharing if at all possible (I already prevent
>> sharing for passthrough mode; if adding a check for private mode with
>> virtualport type='802.1Qbh' would be enough, then I'm happy)
> Yes, I think that would be enough.
> BH does not use passthrou mode because it does not need/want
> to put the lower dev into promiscuous mode.
> Adding a config item would be more flexible, but as of now only
> BH would use it (there are no other cases I can think of), therefore
> it does not seem necessary.

Great! It's always easier to add something later if we determine it's 
necessary, rather than putting it in now and learning later that it's 
redundant or (even worse) incorrect.

Thanks for the firsthand info.

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