Due to latest rewrite of NSS module, we are doing yajl parsing
ourselves. This means, we had to introduce couple of callback
that yajl calls. According to its documentation, a callback can
cancel parsing if it returns a zero value. Well, we do just that
in the string callback (findLeasesParserString()). If the JSON
file we are parsing contains a key that we are not interested in,
zero is returned meaning stop all parsing. This is not correct,
because the JSON file can contain some other keys which are not
harmful for our address translation (e.g. 'client-id').
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Ideally, a software that's translating domain names would iterate
over all addresses the NSS returned, but some software does not
bother (e.g. ping). What happens is that for instance when
installing a guest, it's assigned one IP address but once it's
installed and rebooted it gets a different IP address (because
client ID used for the first DHCP traffic when installing the
guest was generated dynamically and never saved so after reboot
the guest generated new ID which resulted in different IP address
to be assigned). This results in 'ping $domain' not working
properly as it still pings the old IP address. Well, it might -
NSS plugin does not guarantee any order of addresses.
To resolve this problem, we can sort the array just before
returning it to the caller (ping) so that the newer IP addresses
come before older ones.
Reported-by: Andrea Bolognani <abologna@redhat.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
So far the NSS module looks up only hostnames as provided by
guests themselves. However, there are some cases where this is
not enough: e.g. when there's a fresh new guest being installed
(with some generic hostname) say from a live ISO image; or some
(older) systems don't advertise their hostname in DHCP
transactions at all.
In cases like that it would be helpful if we translate domain
name as seen by libvirt too so that users can:
# virsh start $dom && ssh $dom
In order to achieve that new libvirt-guest module is introduced,
while older libvirt module maintains its current behaviour (that
is translating guest provided names into IP addresses).
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
