libvirt: Remove unreachable native QEMU iSCSI initiator config code

Ieb9a03d308495be4e8c54b5c6c0ff781ea7f0559 introduced support for using
QEMU's native iSCSI initiator support way back in Kilo. However this was
only enabled when the LibvirtNetVolumeDriver class was configured as the
``iscsi`` volume driver via the ``[libvirt]/volume_drivers`` configurable.

Unfortunately this configurable was removed in Liberty by
I832820499ec3304132379ad9b9d1ee92c5a75b61 essentially rendering this
``iscsi`` based  code path dead ever since unless operators manually
hacked the now static ``libvirt_volume_drivers`` list within driver.py.

As a result of this and a complete lack of any test coverage in the gate
we can now remove this unreachable code from Nova. It might be desirable
to reintroduce this support later but this should take the form of an
extracted volume driver and a new configurable within nova.conf to
switch between the two available drivers.

Closes-Bug: #1501447
Change-Id: I1043287fe8063c4b2af07c997a931a7097518ca9

Author: lyarwood

nova/tests/unit/virt/libvirt/volume/test_net.py

@@ -14,7 +14,6 @@
 
 import nova.conf
 from nova.tests.unit.virt.libvirt.volume import test_volume
-from nova.virt.libvirt import host
 from nova.virt.libvirt.volume import net
 
 CONF = nova.conf.CONF
@@ -220,28 +219,6 @@ def test_libvirt_rbd_driver_auth_disabled_flags_override(self):
         libvirt_driver.disconnect_volume(connection_info,
                                          mock.sentinel.instance)
 
-    @mock.patch.object(host.Host, 'find_secret')
-    @mock.patch.object(host.Host, 'create_secret')
-    @mock.patch.object(host.Host, 'delete_secret')
-    def test_libvirt_iscsi_net_driver(self, mock_delete, mock_create,
-                                      mock_find):
-        mock_find.return_value = test_volume.FakeSecret()
-        mock_create.return_value = test_volume.FakeSecret()
-        libvirt_driver = net.LibvirtNetVolumeDriver(self.fake_host)
-        connection_info = self.iscsi_connection(self.vol, self.location,
-                                                self.iqn, auth=True)
-        secret_type = 'iscsi'
-        flags_user = connection_info['data']['auth_username']
-        conf = libvirt_driver.get_config(connection_info, self.disk_info)
-        tree = conf.format_dom()
-        self._assertISCSINetworkAndProtocolEquals(tree)
-        self.assertEqual(flags_user, tree.find('./auth').get('username'))
-        self.assertEqual(secret_type, tree.find('./auth/secret').get('type'))
-        self.assertEqual(test_volume.SECRET_UUID,
-                         tree.find('./auth/secret').get('uuid'))
-        libvirt_driver.disconnect_volume(connection_info,
-                                         mock.sentinel.instance)
-
     def test_extend_volume(self):
         device_path = '/dev/fake-dev'
         connection_info = {'data': {'device_path': device_path}}

nova/virt/libvirt/volume/net.py

@@ -13,9 +13,6 @@
 from oslo_log import log as logging
 
 import nova.conf
-from nova import exception
-from nova.i18n import _
-from nova import utils
 from nova.virt.libvirt.volume import volume as libvirt_volume
 
 
@@ -29,30 +26,6 @@ def __init__(self, host):
         super(LibvirtNetVolumeDriver,
               self).__init__(host, is_block_dev=False)
 
-    def _get_secret_uuid(self, conf, password=None):
-        # TODO(mriedem): Add delegation methods to connection (LibvirtDriver)
-        # to call through for these secret CRUD operations so the volume driver
-        # doesn't need to know the internal attributes of the connection
-        # object.
-        secret = self.host.find_secret(conf.source_protocol,
-                                                   conf.source_name)
-        if secret is None:
-            secret = self.host.create_secret(conf.source_protocol,
-                                                         conf.source_name,
-                                                         password)
-        return secret.UUIDString()
-
-    def _delete_secret_by_name(self, connection_info):
-        source_protocol = connection_info['driver_volume_type']
-        netdisk_properties = connection_info['data']
-        if source_protocol == 'rbd':
-            return
-        elif source_protocol == 'iscsi':
-            usage_type = 'iscsi'
-            usage_name = ("%(target_iqn)s/%(target_lun)s" %
-                          netdisk_properties)
-            self.host.delete_secret(usage_type, usage_name)
-
     def _set_auth_config_rbd(self, conf, netdisk_properties):
         # The rbd volume driver in cinder sets auth_enabled if the rbd_user is
         # set in cinder. The rbd auth values from the cinder connection take
@@ -94,13 +67,6 @@ def _set_auth_config_rbd(self, conf, netdisk_properties):
             # secret_type is always hard-coded to 'ceph' in cinder
             conf.auth_secret_type = netdisk_properties['secret_type']
 
-    def _set_auth_config_iscsi(self, conf, netdisk_properties):
-        if netdisk_properties.get('auth_method') == 'CHAP':
-            conf.auth_secret_type = 'iscsi'
-            password = netdisk_properties.get('auth_password')
-            conf.auth_secret_uuid = self._get_secret_uuid(conf, password)
-            conf.auth_username = netdisk_properties['auth_username']
-
     def get_config(self, connection_info, disk_info):
         """Returns xml for libvirt."""
         conf = super(LibvirtNetVolumeDriver,
@@ -114,28 +80,8 @@ def get_config(self, connection_info, disk_info):
         conf.source_ports = netdisk_properties.get('ports', [])
         if conf.source_protocol == 'rbd':
             self._set_auth_config_rbd(conf, netdisk_properties)
-        elif conf.source_protocol == 'iscsi':
-            try:
-                conf.source_name = ("%(target_iqn)s/%(target_lun)s" %
-                                    netdisk_properties)
-                target_portal = netdisk_properties['target_portal']
-            except KeyError:
-                raise exception.InternalError(_("Invalid volume source data"))
-
-            ip, port = utils.parse_server_string(target_portal)
-            if ip == '' or port == '':
-                raise exception.InternalError(_("Invalid target_lun"))
-            conf.source_hosts = [ip]
-            conf.source_ports = [port]
-            self._set_auth_config_iscsi(conf, netdisk_properties)
         return conf
 
-    def disconnect_volume(self, connection_info, instance):
-        """Detach the volume from instance_name."""
-        super(LibvirtNetVolumeDriver,
-              self).disconnect_volume(connection_info, instance)
-        self._delete_secret_by_name(connection_info)
-
     def extend_volume(self, connection_info, instance, requested_size):
         # There is nothing to do for network volumes. Cinder already extended
         # the volume and there is no local block device which needs to be