ovs-external-ids: Better handle VIFs from recently resumed VMs

XAPI doesn't provide a way to look up a VIF entry based on the name, so
we have to locate it by other methods.  Previously, we were breaking up
the name into the domid and device number.  Unfortunately, it can take
XAPI a few seconds to update the domid of the VM, when resuming from a
suspend.  Since we have the VIF UUID, we can just look up the needed
information directly based on that.

Bug #3930

diff --git a/xenserver/usr_share_openvswitch_scripts_ovs-external-ids b/xenserver/usr_share_openvswitch_scripts_ovs-external-ids
index 13c644f0bdf5ab47290744c3eb65e37e28c209c1..07303e3eabd29792c9c75a6b2a7b3491bba08f32 100755 (executable)
--- a/xenserver/usr_share_openvswitch_scripts_ovs-external-ids
+++ b/xenserver/usr_share_openvswitch_scripts_ovs-external-ids
@@ -88,26 +88,24 @@ def get_bridge_id(br_name, default=None):
 # same as "xs-vif-uuid".  This may be overridden by defining a
 # "nicira-iface-id" key in the "other_config" field of the VIF
 # record of XAPI.
-def get_iface_id(if_name, default=None):
+def get_iface_id(if_name, xs_vif_uuid):
     if not if_name.startswith("vif"):
-        return default
-
-    domain,device = if_name.strip("vif").split(".")
+        # Treat whatever was passed into 'xs_vif_uuid' as a default
+        # value for non-VIFs.
+        return xs_vif_uuid
 
     if not init_session():
         s_log.warning("Failed to get interface id %s because"
                 " XAPI session could not be initialized" % if_name)
-        return default
-
-    for n in session.xenapi.VM.get_all():
-        if session.xenapi.VM.get_domid(n) == domain:
-            vifs = session.xenapi.VM.get_VIFs(n)
-            for vif in vifs:
-                rec = session.xenapi.VIF.get_record(vif)
-                if rec['device'] == device:
-                    return rec['other_config'].get('nicira-iface-id', default)
-    return None
+        return xs_vif_uuid
 
+    try:
+        vif = session.xenapi.VIF.get_by_uuid(xs_vif_uuid)
+        rec = session.xenapi.VIF.get_record(vif)
+        return rec['other_config'].get('nicira-iface-id', xs_vif_uuid)
+    except XenAPI.Failure:
+        s_log.warning("Could not find XAPI entry for VIF %s" % if_name)
+        return xs_vif_uuid
 
 def set_external_id(table, record, key, value):
     col = 'external-ids:"' + key + '"="' + value + '"'