Don't make nova-compute depend on iSCSI

Because not all volume drivers require iSCSI it makes sense to not
set the initiator in the connector and let the volume drivers
return an error if iSCSI is required.

bug #1007084

Change-Id: I5da472e5013fdc0c733ecb12b919c1068873bdc6

nova/tests/virt/libvirt/test_libvirt.py

@@ -4520,6 +4520,17 @@ class LibvirtUtilsTestCase(test.TestCase):
         result = libvirt_utils.get_iscsi_initiator()
         self.assertEqual(initiator, result)
 
+    def test_get_missing_iscsi_initiator(self):
+        self.mox.StubOutWithMock(utils, 'execute')
+        file_path = '/etc/iscsi/initiatorname.iscsi'
+        utils.execute('cat', file_path, run_as_root=True).AndRaise(
+            exception.FileNotFound(file_path=file_path)
+        )
+        # Start test
+        self.mox.ReplayAll()
+        result = libvirt_utils.get_iscsi_initiator()
+        self.assertIsNone(result)
+
     def test_create_image(self):
         self.mox.StubOutWithMock(utils, 'execute')
         utils.execute('qemu-img', 'create', '-f', 'raw',

nova/virt/libvirt/driver.py

@@ -929,15 +929,12 @@ class LibvirtDriver(driver.ComputeDriver):
                                'world wide port names'),
                           instance=instance)
 
-        if not self._initiator and not self._fc_wwnns and not self._fc_wwpns:
-            msg = _("No Volume Connector found.")
-            LOG.error(msg)
-            raise exception.NovaException(msg)
-
         connector = {'ip': CONF.my_ip,
-                     'initiator': self._initiator,
                      'host': CONF.host}
 
+        if self._initiator:
+            connector['initiator'] = self._initiator
+
         if self._fc_wwnns and self._fc_wwpns:
             connector["wwnns"] = self._fc_wwnns
             connector["wwpns"] = self._fc_wwpns

nova/virt/libvirt/utils.py

@@ -26,6 +26,7 @@ import os
 from lxml import etree
 from oslo.config import cfg
 
+from nova import exception
 from nova.openstack.common import log as logging
 from nova.openstack.common import processutils
 from nova import utils
@@ -52,7 +53,11 @@ def get_iscsi_initiator():
     """Get iscsi initiator name for this machine."""
     # NOTE(vish) openiscsi stores initiator name in a file that
     #            needs root permission to read.
-    contents = utils.read_file_as_root('/etc/iscsi/initiatorname.iscsi')
+    try:
+        contents = utils.read_file_as_root('/etc/iscsi/initiatorname.iscsi')
+    except exception.FileNotFound:
+        return None
+
     for l in contents.split('\n'):
         if l.startswith('InitiatorName='):
             return l[l.index('=') + 1:].strip()