Log warning if CONF.my_ip is not found on system

Explicitly check if CONF.my_ip is present in any of the network
interfaces then log a warning to alert the operators.

Code borrowed from swift:
http://git.openstack.org/cgit/openstack/swift/tree/swift/common/utils.py#n1545

Closes-Bug: #1419002
Change-Id: I9db5a2f7c5395d1d34ab2eb6d169c62fc4753f73

nova/compute/utils.py

@@ -18,6 +18,7 @@ import itertools
 import string
 import traceback
 
+import netifaces
 from oslo_config import cfg
 from oslo_utils import encodeutils
 
@@ -459,6 +460,31 @@ def get_reboot_type(task_state, current_power_state):
     return reboot_type
 
 
+def get_machine_ips():
+    """Get the machine's ip addresses
+
+    :returns: list of Strings of ip addresses
+    """
+    addresses = []
+    for interface in netifaces.interfaces():
+        iface_data = netifaces.ifaddresses(interface)
+        for family in iface_data:
+            if family not in (netifaces.AF_INET, netifaces.AF_INET6):
+                continue
+            try:
+                for address in iface_data[family]:
+                    addr = address['addr']
+
+                    # If we have an ipv6 address remove the
+                    # %ether_interface at the end
+                    if family == netifaces.AF_INET6:
+                        addr = addr.split('%')[0]
+                    addresses.append(addr)
+            except ValueError:
+                pass
+    return addresses
+
+
 class EventReporter(object):
     """Context manager to report instance action events."""
 

nova/tests/unit/virt/libvirt/test_driver.py

@@ -8105,6 +8105,18 @@ class LibvirtConnTestCase(test.TestCase):
         ip = drvr.get_host_ip_addr()
         self.assertEqual(ip, CONF.my_ip)
 
+    @mock.patch.object(libvirt_driver.LOG, 'warn')
+    @mock.patch('nova.compute.utils.get_machine_ips')
+    def test_get_host_ip_addr_failure(self, mock_ips, mock_log):
+        mock_ips.return_value = ['8.8.8.8', '75.75.75.75']
+        drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
+        drvr.get_host_ip_addr()
+        mock_log.assert_called_once_with(u'my_ip address (%(my_ip)s) was '
+                                         u'not found on any of the '
+                                         u'interfaces: %(ifaces)s',
+                                         {'ifaces': '8.8.8.8, 75.75.75.75',
+                                          'my_ip': mock.ANY})
+
     def test_conn_event_handler(self):
         self.mox.UnsetStubs()
         drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)

nova/virt/libvirt/driver.py

@@ -2439,6 +2439,11 @@ class LibvirtDriver(driver.ComputeDriver):
 
     @staticmethod
     def get_host_ip_addr():
+        ips = compute_utils.get_machine_ips()
+        if CONF.my_ip not in ips:
+            LOG.warn(_LW('my_ip address (%(my_ip)s) was not found on '
+                         'any of the interfaces: %(ifaces)s'),
+                     {'my_ip': CONF.my_ip, 'ifaces': ", ".join(ips)})
         return CONF.my_ip
 
     def get_vnc_console(self, context, instance):