To those reading the thread, this is the Nova commit[1] that introduced
this change:
commit 2390857d7ae625dcd18a72b2980f2d862b776623
Author: Dan Smith <dansmith(a)redhat.com>
Date: Wed Feb 19 12:02:45 2014 -0800
Make libvirt wait for neutron to confirm plugging before boot
This makes the libvirt driver use the instance event mechanism to
wait for neutron to confirm that VIF plugging is complete before
actually starting the VM.
Here we introduce a new configuration option of vif_plugging_is_fatal
which allows us to control whether a failure to hear back from
neutron is something that should kill the current operation. In
cases where consoles are not provided for the guest, failing is
the only reasonable action, but if consoles *are* provided, it may
be advantageous to still allow the guest to boot and be accessed
out of band.
In order to properly reflect the neutron failure in the instance's
fault property, this also extends manager to catch and re-raise
the VirtualInterfaceCreateException during spawn(). Also, since
the oslo.messaging merge, we weren't declaring expected exceptions
for run_instance() which this also fixes.
DocImpact: This requires a neutron that is aware of these events
when using nova with neutron, or a configuration that
causes nova not to expect/wait for these events.
Related to blueprint admin-event-callback-api
[1]
https://review.openstack.org/#/c/74832/26
--
/kashyap