Kaminario K2: Support duplicated FQDN in network

The Kaminario K2 driver uses the FQDN of the node that is doing the
attach as an unique identifier to map the volume.

The problem is that the FQDN is not always unique, there are
environments where the same FQDN can be found in different systems, and
in those cases if both try to attach volumes the second system will
fail.

One example of this happening would be on a QA environment where you are
creating VMs and they all have names like controller-0.localdomain and
compute-0.localdomain.

This patch adds a configuration option to the K2 driver called
`unique_fqdn_network` to support these kind of environments.

Closes-Bug: #1720147
Change-Id: I2099b804a2043078e50a5a9e14c1497861576f61

cinder/tests/unit/volume/drivers/test_kaminario.py

@@ -13,6 +13,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 """Unit tests for kaminario driver."""
+import re
+
 import mock
 from oslo_utils import units
 import time
@@ -137,6 +139,7 @@ class TestKaminarioISCSI(test.TestCase):
         self.conf = mock.Mock(spec=configuration.Configuration)
         self.conf.kaminario_dedup_type_name = "dedup"
         self.conf.volume_dd_blocksize = 2
+        self.conf.unique_fqdn_network = True
 
     def _setup_driver(self):
         self.driver = (kaminario_iscsi.
@@ -529,6 +532,16 @@ class TestKaminarioISCSI(test.TestCase):
                                                              'test')
         self.assertIsNone(result)
 
+    def test_get_initiator_host_name(self):
+        result = self.driver.get_initiator_host_name(CONNECTOR)
+        self.assertEqual(CONNECTOR['host'], result)
+
+    def test_get_initiator_host_name_unique(self):
+        self.driver.configuration.unique_fqdn_network = False
+        result = self.driver.get_initiator_host_name(CONNECTOR)
+        expected = re.sub('[:.]', '_', CONNECTOR['initiator'][::-1][:32])
+        self.assertEqual(expected, result)
+
 
 class TestKaminarioFC(TestKaminarioISCSI):
 
@@ -555,3 +568,11 @@ class TestKaminarioFC(TestKaminarioISCSI):
         """Test terminate_connection."""
         result = self.driver.terminate_connection(self.vol, CONNECTOR)
         self.assertIn('data', result)
+
+    def test_get_initiator_host_name_unique(self):
+        connector = CONNECTOR.copy()
+        del connector['initiator']
+        self.driver.configuration.unique_fqdn_network = False
+        result = self.driver.get_initiator_host_name(connector)
+        expected = re.sub('[:.]', '_', connector['wwnns'][0][::-1][:32])
+        self.assertEqual(expected, result)

cinder/volume/drivers/kaminario/kaminario_common.py

@@ -50,7 +50,16 @@ kaminario_opts = [
     cfg.BoolOpt('auto_calc_max_oversubscription_ratio',
                 default=False,
                 help="K2 driver will calculate max_oversubscription_ratio "
-                     "on setting this option as True.")]
+                     "on setting this option as True."),
+    cfg.BoolOpt('unique_fqdn_network',
+                default=True,
+                help="Whether or not our private network has unique FQDN on "
+                     "each initiator or not.  For example networks with QA "
+                     "systems usually have multiple servers/VMs with the same "
+                     "FQDN.  When true this will create host entries on K2 "
+                     "using the FQDN, when false it will use the reversed "
+                     "IQN/WWNN."),
+]
 
 CONF = cfg.CONF
 CONF.register_opts(kaminario_opts, group=configuration.SHARED_CONF_GROUP)
@@ -826,13 +835,20 @@ class KaminarioCinderDriver(cinder.volume.driver.ISCSIDriver):
                       'kaminario:replication': True}
 
     def get_initiator_host_name(self, connector):
-        """Return the initiator host name.
+        """Return the initiator host name or unique ID.
+
+        Unique ID when configuration's unique_fqdn_network is false will be
+        the reversed IQN/WWPNS.
 
         Valid characters: 0-9, a-z, A-Z, '-', '_'
         All other characters are replaced with '_'.
         Total characters in initiator host name: 32
         """
-        return re.sub('[^0-9a-zA-Z-_]', '_', connector.get('host', ''))[:32]
+        name = connector.get('initiator',
+                             connector.get('wwnns', [''])[0])[::-1]
+        if self.configuration.unique_fqdn_network:
+            name = connector.get('host', name)
+        return re.sub('[^0-9a-zA-Z-_]', '_', name[:32])
 
     def get_volume_group_name(self, vid):
         """Return the volume group name."""

releasenotes/notes/k2-non-unique-fqdns-b62a269a26fd53d5.yaml

@@ -0,0 +1,6 @@
+---
+issues:
+  - |
+    Kaminario K2 now supports networks with duplicated FQDNs via configuration
+    option `unique_fqdn_network` so attaching in these networks will work
+    (bug #1720147).