Add Qos support for Unity Cinder driver

This commit allows QoS (maxIOPS, maxBWS) to be set on
Unity volume.

To enable this function, User needs to set `maxIOPS` and/or
`maxBWS` on qos specs and associate it with a volume type.

Author: Peter Wang

README.md

@@ -187,3 +187,16 @@ Over subscription allows that the sum of all volumes' capacity (provisioned capa
 `max_over_subscription_ratio` in the back-end section is the ratio of provisioned capacity over total capacity.
 
 The default value of `max_over_subscription_ratio` is 20.0, which means the provisioned capacity can be 20 times of the total capacity. If the value of this ratio is set larger than 1.0, the provisioned capacity can exceed the total capacity.
+
+## QoS support
+
+Unity driver now supports QoS. To enable this function, User needs to set
+`maxIOPS` and/or `maxBWS` on QoS specs and associate it with a volume type.
+
+Example:
+
+    cinder qos-create unity_qos consumer=”back-end” maxIOPS=1000 maxBWS=1000
+    cinder qos-associate <qos-spec-id> <volume-type-id>
+
+
+NOTE: Unity driver only supports QoS spec whose consumer is set to `back-end`.

emc_unity.py

@@ -12,6 +12,7 @@
 #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 #    License for the specific language governing permissions and limitations
 #    under the License.
+
 """
 Drivers for EMC Unity array based on RESTful API.
 """
@@ -45,12 +46,17 @@
 LOG = logging.getLogger(__name__)
 
 CONF = cfg.CONF
-VERSION = '00.02.01'
+VERSION = '00.02.02'
 
 GiB = 1024 * 1024 * 1024
 ENABLE_TRACE = False
 EMC_OPENSTACK_DUMMY_LUN = 'openstack_dummy_lun'
 
+QOS_MAX_IOPS = 'maxIOPS'
+QOS_MAX_BWS = 'maxBWS'
+QOS_CONSUMER_BACKEND = 'back-end'
+QOS_CONSUMER_FRONTEND = 'front-end'
+
 loc_opts = [
     cfg.StrOpt('storage_pool_names',
                default=None,
@@ -123,6 +129,7 @@ class EMCUnityRESTClient(object):
     HostLUNAccessEnum_NoAccess = 0
     HostLUNAccessEnum_Production = 1
     LUN_NAME_IN_USE = 108007744
+    POLICY_NAME_IN_USE = 151032071
 
     def __init__(self, host, port=443, user='Local/admin',
                  password='', realm='Security Realm',
@@ -349,13 +356,17 @@ def update_consistencygroup(self, group_id, add_luns=None,
         err, resp = self._request(cg_update_url, req_data)
         return err, resp
 
-    def create_lun(self, pool_id, name, size, **kwargs):
+    def create_lun(self, pool_id, name, size, is_thin=False,
+                   limit_policy_id=None):
         lun_create_url = '/api/types/storageResource/action/createLun'
         lun_parameters = {'pool': {"id": pool_id},
                           'isThinEnabled': True,
                           'size': size}
-        if 'is_thin' in kwargs:
-            lun_parameters['isThinEnabled'] = kwargs['is_thin']
+        if is_thin:
+            lun_parameters['isThinEnabled'] = is_thin
+        if limit_policy_id:
+            lun_parameters['ioLimitParameters'] = {
+                'ioLimitPolicy': {'id': limit_policy_id}}
         # More Advance Feature
         data = {'name': name,
                 'description': name,
@@ -534,6 +545,33 @@ def modify_lun_name(self, lun_id, new_name):
                 raise exception.VolumeBackendAPIException(
                     data=reason)
 
+    def get_limit_policy(self, name):
+        """Get existing IO limits by name."""
+        return self._filter_by_field(
+            'ioLimitPolicy', 'name', name,
+            ('id', 'maxIOPS::ioLimitRules.maxIOPS',
+             'maxKBPS::ioLimitRules.maxKBPS'))
+
+    def create_limit_policy(self, name, max_iops=None, max_kbps=None):
+        """Create host IO limits."""
+        create_limit_url = \
+            '/api/types/ioLimitPolicy/instances'
+        data = {'name': name, 'ioLimitRules': []}
+        rule = {}
+        if max_iops:
+            rule.update({'maxIOPS': max_iops})
+        if max_kbps:
+            rule.update({'maxKBPS': max_kbps})
+        rule.update({'name': name})
+        data['ioLimitRules'].append(rule)
+        err, resp = self._request(create_limit_url, data)
+        if err:
+            if err['errorCode'] == self.POLICY_NAME_IN_USE:
+                return self.get_limit_policy(name)[0]
+            else:
+                raise exception.VolumeBackendAPIException(err['messages'])
+        return resp['content']
+
 
 class ArrangeHostTask(task.Task):
     def __init__(self, helper, connector):
@@ -748,6 +786,22 @@ def _get_volumetype_extraspecs(self, volume):
 
         return specs
 
+    def _get_qos_specs(self, volume_type):
+        qos_specs_id = (None if not volume_type
+                        else volume_type['qos_specs_id'])
+        emc_qos = {}
+        if not qos_specs_id:
+            return {}, None
+        if qos_specs_id:
+            qos_specs = volume_type['qos_specs']
+            for qos_spec in qos_specs:
+                emc_qos[qos_spec['key']] = qos_spec['value']
+
+        if emc_qos['consumer'] == QOS_CONSUMER_FRONTEND:
+            # We do not handle front-end qos specs
+            return {}, None
+        return emc_qos, qos_specs_id
+
     def _load_provider_location(self, provider_location):
         pl_dict = {}
         for item in provider_location.split('|'):
@@ -863,7 +917,7 @@ def create_cgsnapshot(self, cgsnapshot, snapshots):
                     snap_name)
             else:
                 raise exception.VolumeBackendAPIException(data=err['messages'])
-        model_update = {'status': cgsnapshot['status']}
+        model_update = {'status': 'available'}
         for snapshot in snapshots:
             snapshot['status'] = 'available'
         return model_update, snapshots
@@ -891,6 +945,7 @@ def create_volume(self, volume):
         name = volume['name']
         size = volume['size'] * GiB
         extra_specs = self._get_volumetype_extraspecs(volume)
+        qos_specs, qos_specs_id = self._get_qos_specs(volume['volume_type'])
         k = 'storagetype:provisioning'
         is_thin = False
         if k in extra_specs:
@@ -903,9 +958,20 @@ def create_volume(self, volume):
                 msg = _('Value %(v)s of %(k)s is invalid') % {'k': k, 'v': v}
                 LOG.error(msg)
                 raise exception.VolumeBackendAPIException(data=msg)
+        limit_policy_id = None
+        if qos_specs_id:
+            limit_policy = self.client.get_limit_policy(qos_specs_id)
+            if not limit_policy:
+                limit_policy = self.client.create_limit_policy(
+                    qos_specs_id,
+                    max_iops=qos_specs.get(QOS_MAX_IOPS, None),
+                    max_kbps=qos_specs.get(QOS_MAX_BWS, None))
+            else:
+                limit_policy = limit_policy[0]
+            limit_policy_id = limit_policy['id']
         err, lun = self.client.create_lun(
             self._get_target_storage_pool_id(volume), name, size,
-            is_thin=is_thin)
+            is_thin=is_thin, limit_policy_id=limit_policy_id)
         if err:
             raise exception.VolumeBackendAPIException(data=err['messages'])