FIP missing on SI VM ports

This fix only adds errors logs to the flow
so any future fips missing from SI VM ports
can be root-caused.

Change-Id: I04f96019cf132a61aa1593c30cf633f70157fb9f
Partial-Bug: #1554165

src/config/svc-monitor/svc_monitor/instance_manager.py

@@ -155,6 +155,8 @@ def _link_fip_to_vmi(self, vmi_id, fip_id):
         fip = FloatingIpSM.get(fip_id)
         vmi = VirtualMachineInterfaceSM.get(vmi_id)
         if not fip or not vmi:
+            self.logger.error("Failed associating fip %s to vmi %s" %
+                              (fip_id, vmi_id))
             return
         if fip_id in vmi.floating_ips:
             return
@@ -784,9 +786,16 @@ def add_fip_to_vip_vmi(self, fip):
         if not vip_vmi:
             return
 
+        if not vip_vmi.instance_ips:
+            self.logger.error("VMI %s missing instance_ip backrefs" %
+                               vip_vmi.uuid)
+            return
+
         for iip_id in vip_vmi.instance_ips:
             iip = InstanceIpSM.get(iip_id)
             if not iip:
+                self.logger.error("Instance IP object missing for iip_id %s" \
+                                   % iip_id)
                 continue
             for vmi_id in iip.virtual_machine_interfaces:
                 if vmi_id == vip_vmi.uuid: