[libvirt] RFC: API to report guest IP address(es)

Michal Privoznik mprivozn at redhat.com
Wed Feb 8 11:30:16 UTC 2012


Hi,

Now we have qemu guest agent it is possible for us to:

1) extend guest agent to report IP addresses (not trivial among OSes).

2) Write API which will report these to mgmt application.

One thing that I am not sure about and would like you to ask is:
how should the API look like?
In addition, we have this nwfilter which already learns host interfaces
address (yeah, only one per interface).

What scenarios are we facing here?
1) It is impossible (in general) to tie guest interface with the host
interface because guest can change  MAC address of any interface and
this change is not propagated to the outside world. Therefore vnet1 can
be eth0 or eth1 or even hello_i_am_funky_interface99.

2) Guest can create virtual interfaces within itself and therefore
create a totally different structure than observed from outside, e.g.
bonding.

3) Interface can have multiple addresses or even none.

Therefore I lean to something like:

int virDomainGetIPAddresses(virDomainPtr dom, char **addr[], int
*addr_size);

That is - simply return an array of IPs in string format (yes, allocated
by us) and leave mgmt application to decide what to do with that.

Any thoughts?




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