Re: [libvirt] [PATCH 0/3] Prevent removing a in-used static bridge and destroying a in-used virtual network
On 02/03/2015 11:47 AM, Michal Privoznik wrote:
On 02.02.2015 15:08, Lin Ma wrote:
> * Get the live state info of a virtual network through netcf in networkGetXMLDesc.
> * Add --system flag for net-dumpxml to show the live state info.
> * Check the live state info in net-destroy.
> * Add --force flag for net-destroy to forcibly destroy the virtual network.
> * Check the transient interfaces info in iface-unbridge.
>
> ---
> Lin Ma (3):
> bridge_driver: Return the live state info of a given virtual network
> virsh: prevent destroying a in-used network for net-destroy
> virsh: prevent removing a in-used bridge for iface-unbridge
>
> include/libvirt/libvirt-network.h | 1 +
> src/Makefile.am | 3 +
> src/network/bridge_driver.c | 141 ++++++++++++++++++++++++++++++++++-
> src/network/bridge_driver_platform.h | 7 ++
> tests/Makefile.am | 4 +
> tools/virsh-interface.c | 25 ++++++-
> tools/virsh-network.c | 62 ++++++++++++++-
> tools/virsh.pod | 8 +-
> 8 files changed, 241 insertions(+), 10 deletions(-)
>
So I've spent some time thinking about this. I don't really like the
idea of producing completely different XML (it doesn't even have
<network/> as its root element!). But I see what you're trying to
achieve. How about putting the bridged interfaces into the network
definition (on request signalized by a flag, of course).
I think that if we're going to add the list of connected guest devices
to a network's status, that it should just always be there - adding a
new flag for every little bit of different status sets a bad precedent
and sets us up to have an infinitely increasing number of flags.
Like I mentioned in my response to one of the patches, I think this
information is better gathered and maintained by the bridge driver as
guests connect to / disconnect from a network; this avoids the necessity
of dragging netcf into the picture and allows much better information -
the name of the domain using each interface can be included.
I think we've come to a point where we need to introduce live and config
XML (like we have for domains). We already have that to some extent, but
not truly.
I think the situation is more that we have live and config XML, but
there may be a small problem here and there. As a matter of fact, a long
time ago virsh wasn't using the live XML to edit a network, and this was
causing problems (e.g. if you tried to edit a network twice without
restarting it, the second time you would lose all the changes from the
first edit).
On the other hand, looking into virNetworkDefFormat(), there's this
'@connections' attribute to the <network/> element which is a nonzero
integer if the network is in use. Won't that suffice for what you're
trying to achieve?
In my opinion, yes - that's exactly the type of thing it was intended
for :-)