[libvirt] [PATCHv2 0/7] interface: new public API for networkconfig change transactions

[Laine Stump]

On 05/19/2011 06:14 PM, Christian Benvenuti (benve) wrote:
> I have one generic question.
> I know it is not a new problem, and it is not necessarily something
> worth investing time and code on, but what if the admin
> (directly or indirectly by activating some features)
> changes the interface configuration in between a BEGIN and
> a ROLLBACK with commands that do not go through virsh/libvirtd?
> Would ROLLBACK rollback those changes too?

Yes, it would. This is only because of the particular implementation in 
the netcf library, though. ncf_change_begin() saves off a copy of all 
the network config files to a "snapshot" directory; ncf_change_commit() 
deletes that snapshot, and ncf_change_rollback() copies back the files 
that were put in the snapshot directory during ncf_change_begin().

You can see the backend of these functions (implemented as a shell 
script so that it can run at boottime) at:

     https://fedorahosted.org/pipermail/netcf-devel/2011-May/000562.html

> Does it make sense for libvirtd to subscribe to the relevant
> Netlink multicast groups to listen for such changes and flag
> an interface as "tainted" in such case? This way it may
> be able to generate a log or ask for a sort of extra "--force"
> parameter for the ROLLBACK case.

That may be a nice thing to do, but isn't necessary for the initial 
implementation.