diff --git a/watcher/datasource/base.py b/watcher/datasource/base.py
index cd4ed4e9b..4a920d0a8 100644
--- a/watcher/datasource/base.py
+++ b/watcher/datasource/base.py
@@ -18,44 +18,18 @@ import abc
 
 class DataSourceBase(object):
 
-    METRIC_MAP = dict(
-        ceilometer=dict(host_cpu_usage='compute.node.cpu.percent',
-                        instance_cpu_usage='cpu_util',
-                        instance_l3_cache_usage='cpu_l3_cache',
-                        host_outlet_temp=(
-                            'hardware.ipmi.node.outlet_temperature'),
-                        host_airflow='hardware.ipmi.node.airflow',
-                        host_inlet_temp='hardware.ipmi.node.temperature',
-                        host_power='hardware.ipmi.node.power',
-                        instance_ram_usage='memory.resident',
-                        instance_ram_allocated='memory',
-                        instance_root_disk_size='disk.root.size',
-                        host_memory_usage='hardware.memory.used', ),
-        gnocchi=dict(host_cpu_usage='compute.node.cpu.percent',
-                     instance_cpu_usage='cpu_util',
-                     instance_l3_cache_usage='cpu_l3_cache',
-                     host_outlet_temp='hardware.ipmi.node.outlet_temperature',
-                     host_airflow='hardware.ipmi.node.airflow',
-                     host_inlet_temp='hardware.ipmi.node.temperature',
-                     host_power='hardware.ipmi.node.power',
-                     instance_ram_usage='memory.resident',
-                     instance_ram_allocated='memory',
-                     instance_root_disk_size='disk.root.size',
-                     host_memory_usage='hardware.memory.used'
-                     ),
-        monasca=dict(host_cpu_usage='cpu.percent',
-                     instance_cpu_usage='vm.cpu.utilization_perc',
-                     instance_l3_cache_usage=None,
-                     host_outlet_temp=None,
-                     host_airflow=None,
-                     host_inlet_temp=None,
-                     host_power=None,
-                     instance_ram_usage=None,
-                     instance_ram_allocated=None,
-                     instance_root_disk_size=None,
-                     host_memory_usage=None
-                     ),
-    )
+    METRIC_MAP = dict(host_cpu_usage=None,
+                      instance_cpu_usage=None,
+                      instance_l3_cache_usage=None,
+                      host_outlet_temp=None,
+                      host_airflow=None,
+                      host_inlet_temp=None,
+                      host_power=None,
+                      instance_ram_usage=None,
+                      instance_ram_allocated=None,
+                      instance_root_disk_size=None,
+                      host_memory_usage=None
+                      )
 
     @abc.abstractmethod
     def statistic_aggregation(self, resource_id=None, meter_name=None,
diff --git a/watcher/datasource/ceilometer.py b/watcher/datasource/ceilometer.py
index 3965e3b41..eb08f7fe5 100644
--- a/watcher/datasource/ceilometer.py
+++ b/watcher/datasource/ceilometer.py
@@ -34,7 +34,18 @@ LOG = log.getLogger(__name__)
 class CeilometerHelper(base.DataSourceBase):
 
     NAME = 'ceilometer'
-    METRIC_MAP = base.DataSourceBase.METRIC_MAP['ceilometer']
+    METRIC_MAP = dict(host_cpu_usage='compute.node.cpu.percent',
+                      instance_cpu_usage='cpu_util',
+                      instance_l3_cache_usage='cpu_l3_cache',
+                      host_outlet_temp='hardware.ipmi.node.outlet_temperature',
+                      host_airflow='hardware.ipmi.node.airflow',
+                      host_inlet_temp='hardware.ipmi.node.temperature',
+                      host_power='hardware.ipmi.node.power',
+                      instance_ram_usage='memory.resident',
+                      instance_ram_allocated='memory',
+                      instance_root_disk_size='disk.root.size',
+                      host_memory_usage='hardware.memory.used',
+                      )
 
     def __init__(self, osc=None):
         """:param osc: an OpenStackClients instance"""
diff --git a/watcher/datasource/gnocchi.py b/watcher/datasource/gnocchi.py
index bd09ed2b9..41ae38b1d 100644
--- a/watcher/datasource/gnocchi.py
+++ b/watcher/datasource/gnocchi.py
@@ -35,7 +35,18 @@ LOG = log.getLogger(__name__)
 class GnocchiHelper(base.DataSourceBase):
 
     NAME = 'gnocchi'
-    METRIC_MAP = base.DataSourceBase.METRIC_MAP['gnocchi']
+    METRIC_MAP = dict(host_cpu_usage='compute.node.cpu.percent',
+                      instance_cpu_usage='cpu_util',
+                      instance_l3_cache_usage='cpu_l3_cache',
+                      host_outlet_temp='hardware.ipmi.node.outlet_temperature',
+                      host_airflow='hardware.ipmi.node.airflow',
+                      host_inlet_temp='hardware.ipmi.node.temperature',
+                      host_power='hardware.ipmi.node.power',
+                      instance_ram_usage='memory.resident',
+                      instance_ram_allocated='memory',
+                      instance_root_disk_size='disk.root.size',
+                      host_memory_usage='hardware.memory.used',
+                      )
 
     def __init__(self, osc=None):
         """:param osc: an OpenStackClients instance"""
diff --git a/watcher/datasource/manager.py b/watcher/datasource/manager.py
index b38beb474..31303b213 100644
--- a/watcher/datasource/manager.py
+++ b/watcher/datasource/manager.py
@@ -14,7 +14,6 @@
 # limitations under the License.
 
 from watcher.common import exception
-from watcher.datasource import base
 from watcher.datasource import ceilometer as ceil
 from watcher.datasource import gnocchi as gnoc
 from watcher.datasource import monasca as mon
@@ -28,7 +27,11 @@ class DataSourceManager(object):
         self._ceilometer = None
         self._monasca = None
         self._gnocchi = None
-        self.metric_map = base.DataSourceBase.METRIC_MAP
+        self.metric_map = {
+            mon.MonascaHelper.NAME: mon.MonascaHelper.METRIC_MAP,
+            gnoc.GnocchiHelper.NAME: gnoc.GnocchiHelper.METRIC_MAP,
+            ceil.CeilometerHelper.NAME: ceil.CeilometerHelper.METRIC_MAP
+        }
         self.datasources = self.config.datasources
 
     @property
diff --git a/watcher/datasource/monasca.py b/watcher/datasource/monasca.py
index 4c948af3f..2847cc73f 100644
--- a/watcher/datasource/monasca.py
+++ b/watcher/datasource/monasca.py
@@ -28,7 +28,18 @@ from watcher.datasource import base
 class MonascaHelper(base.DataSourceBase):
 
     NAME = 'monasca'
-    METRIC_MAP = base.DataSourceBase.METRIC_MAP['monasca']
+    METRIC_MAP = dict(host_cpu_usage='cpu.percent',
+                      instance_cpu_usage='vm.cpu.utilization_perc',
+                      instance_l3_cache_usage=None,
+                      host_outlet_temp=None,
+                      host_airflow=None,
+                      host_inlet_temp=None,
+                      host_power=None,
+                      instance_ram_usage=None,
+                      instance_ram_allocated=None,
+                      instance_root_disk_size=None,
+                      host_memory_usage=None,
+                      )
 
     def __init__(self, osc=None):
         """:param osc: an OpenStackClients instance"""
diff --git a/watcher/tests/datasource/test_manager.py b/watcher/tests/datasource/test_manager.py
index ba6018835..c0bd5df9d 100644
--- a/watcher/tests/datasource/test_manager.py
+++ b/watcher/tests/datasource/test_manager.py
@@ -17,23 +17,28 @@
 import mock
 
 from watcher.common import exception
-from watcher.datasource import gnocchi as gnoc
 from watcher.datasource import manager as ds_manager
 from watcher.tests import base
 
 
 class TestDataSourceManager(base.BaseTestCase):
 
-    @mock.patch.object(gnoc, 'GnocchiHelper')
-    def test_get_backend(self, mock_gnoc):
+    def test_get_backend(self):
         manager = ds_manager.DataSourceManager(
             config=mock.MagicMock(
                 datasources=['gnocchi', 'ceilometer', 'monasca']),
             osc=mock.MagicMock())
-        backend = manager.get_backend(['host_cpu_usage',
-                                       'instance_cpu_usage'])
+        backend = manager.get_backend(['host_cpu_usage', 'instance_cpu_usage'])
         self.assertEqual(backend, manager.gnocchi)
 
+    def test_get_backend_order(self):
+        manager = ds_manager.DataSourceManager(
+            config=mock.MagicMock(
+                datasources=['monasca', 'ceilometer', 'gnocchi']),
+            osc=mock.MagicMock())
+        backend = manager.get_backend(['host_cpu_usage', 'instance_cpu_usage'])
+        self.assertEqual(backend, manager.monasca)
+
     def test_get_backend_wrong_metric(self):
         manager = ds_manager.DataSourceManager(
             config=mock.MagicMock(