Allow nodegroups with node_count equal to 0

This change allows users to create clusters and nodegroups with
node_count equal to 0. Also adds support for resizing existing
nodegroups to 0.

Change-Id: Id63459d0fe9836e678bb7569f23d29eabc225e9e
story: 2007851
task: 40145
Signed-off-by: Diogo Guerra <diogo.filipe.tomas.guerra@cern.ch>

magnum/api/controllers/v1/cluster.py

@@ -105,7 +105,7 @@ class Cluster(base.APIBase):
                           default=None)
     """The name of the nova ssh keypair"""
 
-    node_count = wsme.wsattr(wtypes.IntegerType(minimum=1), default=1)
+    node_count = wsme.wsattr(wtypes.IntegerType(minimum=0), default=1)
     """The node count for this cluster. Default to 1 if not set"""
 
     master_count = wsme.wsattr(wtypes.IntegerType(minimum=1), default=1)

magnum/api/controllers/v1/cluster_actions.py

@@ -44,7 +44,7 @@ class ClusterResizeRequest(base.APIBase):
     This class enforces type checking and value constraints.
     """
 
-    node_count = wsme.wsattr(wtypes.IntegerType(minimum=1), mandatory=True)
+    node_count = wsme.wsattr(wtypes.IntegerType(minimum=0), mandatory=True)
     """The expected node count after resize."""
 
     nodes_to_remove = wsme.wsattr([wtypes.text], mandatory=False,

magnum/api/controllers/v1/nodegroup.py

@@ -98,18 +98,18 @@ class NodeGroup(base.APIBase):
     node_addresses = wsme.wsattr([wtypes.text], readonly=True)
     """IP addresses of nodegroup nodes"""
 
-    node_count = wsme.wsattr(wtypes.IntegerType(minimum=1), default=1)
+    node_count = wsme.wsattr(wtypes.IntegerType(minimum=0), default=1)
     """The node count for this nodegroup. Default to 1 if not set"""
 
     role = wsme.wsattr(wtypes.StringType(min_length=1, max_length=255),
                        default='worker')
     """The role of the nodes included in this nodegroup"""
 
-    min_node_count = wsme.wsattr(wtypes.IntegerType(minimum=1), default=1)
-    """The minimum allowed nodes for this nodegroup. Default to 1 if not set"""
+    min_node_count = wsme.wsattr(wtypes.IntegerType(minimum=0), default=0)
+    """The minimum allowed nodes for this nodegroup. Default to 0 if not set"""
 
-    max_node_count = wsme.wsattr(wtypes.IntegerType(minimum=1), default=None)
-    """The maximum allowed nodes for this nodegroup. Default to 1 if not set"""
+    max_node_count = wsme.wsattr(wtypes.IntegerType(minimum=0), default=None)
+    """The maximum allowed nodes for this nodegroup."""
 
     is_default = types.BooleanType()
     """Specifies is a nodegroup was created by default or not"""

magnum/api/controllers/v1/types.py

@@ -210,11 +210,11 @@ class JsonPatchType(wtypes.Base):
             raise wsme.exc.ClientSideError(msg % patch.path)
 
         if patch.op != 'remove':
-            if not patch.value:
+            if patch.value is None or patch.value == wtypes.Unset:
                 msg = _("'add' and 'replace' operations needs value")
                 raise wsme.exc.ClientSideError(msg)
 
         ret = {'path': patch.path, 'op': patch.op}
-        if patch.value:
+        if patch.value is not None and patch.value != wtypes.Unset:
             ret['value'] = patch.value
         return ret

magnum/api/controllers/versions.py

@@ -17,16 +17,6 @@ from webob import exc
 
 from magnum.i18n import _
 
-# NOTE(yuntong): v1.0 is reserved to indicate Kilo's API, but is not presently
-#             supported by the API service. All changes between Kilo and the
-#             point where we added microversioning are considered backwards-
-#             compatible, but are not specifically discoverable at this time.
-#
-#             The v1.1 version indicates this "initial" version as being
-#             different from Kilo (v1.0), and includes the following changes:
-#
-#             Add details of new api versions here:
-
 #
 # For each newly added microversion change, update the API version history
 # string below with a one or two line description. Also update
@@ -42,10 +32,11 @@ REST_API_VERSION_HISTORY = """REST API Version History:
     * 1.7 - Add resize API
     * 1.8 - Add upgrade API
     * 1.9 - Add nodegroup API
+    * 1.10 - Allow nodegroups with 0 nodes
 """
 
 BASE_VER = '1.1'
-CURRENT_MAX_VER = '1.9'
+CURRENT_MAX_VER = '1.10'
 
 
 class Version(object):

magnum/api/rest_api_version_history.rst

@@ -75,3 +75,12 @@ user documentation.
 
   An admin user can set/update/delete/list quotas for the given tenant.
   A non-admin user can get self quota information.
+
+
+1.10
+---
+
+  Allow nodegroups with 0 nodes
+
+  Allow the cluster to be created with node_count = 0 as well as to update
+  existing nodegroups to have 0 nodes.

magnum/conductor/utils.py

@@ -18,6 +18,7 @@ from pycadf import cadftaxonomy as taxonomy
 from pycadf import cadftype
 from pycadf import eventfactory
 from pycadf import resource
+from wsme import types as wtypes
 
 from magnum.common import clients
 from magnum.common import rpc
@@ -176,6 +177,7 @@ def _get_nodegroup_object(context, cluster, node_count, is_master=False):
     ng.image_id = cluster.cluster_template.image_id
     ng.docker_volume_size = (cluster.docker_volume_size or
                              cluster.cluster_template.docker_volume_size)
+
     if is_master:
         ng.flavor_id = (cluster.master_flavor_id or
                         cluster.cluster_template.master_flavor_id)
@@ -183,6 +185,11 @@ def _get_nodegroup_object(context, cluster, node_count, is_master=False):
     else:
         ng.flavor_id = cluster.flavor_id or cluster.cluster_template.flavor_id
         ng.role = "worker"
+    if (cluster.labels != wtypes.Unset and cluster.labels is not None
+       and 'min_node_count' in cluster.labels):
+        ng.min_node_count = cluster.labels['min_node_count']
+    else:
+        ng.min_node_count = 0
     ng.name = "default-%s" % ng.role
     ng.is_default = True
     ng.status = fields.ClusterStatus.CREATE_IN_PROGRESS

magnum/drivers/k8s_fedora_atomic_v1/templates/kubecluster.yaml

@@ -842,7 +842,7 @@ parameters:
     type: number
     description: >
       minimum node count of cluster workers when doing scale down
-    default: 1
+    default: 0
 
   max_node_count:
     type: number

magnum/drivers/k8s_fedora_coreos_v1/templates/kubecluster.yaml

@@ -858,7 +858,7 @@ parameters:
     type: number
     description: >
       minimum node count of cluster workers when doing scale down
-    default: 1
+    default: 0
 
   max_node_count:
     type: number

magnum/objects/nodegroup.py

@@ -26,8 +26,9 @@ from magnum.objects import fields as m_fields
 class NodeGroup(base.MagnumPersistentObject, base.MagnumObject,
                 base.MagnumObjectDictCompat):
     # Version 1.0: Initial version
+    # Version 1.1: min_node_count defaults to 0
 
-    VERSION = '1.0'
+    VERSION = '1.1'
 
     dbapi = dbapi.get_instance()
 
@@ -45,7 +46,7 @@ class NodeGroup(base.MagnumPersistentObject, base.MagnumObject,
         'node_count': fields.IntegerField(nullable=False, default=1),
         'role': fields.StringField(),
         'max_node_count': fields.IntegerField(nullable=True),
-        'min_node_count': fields.IntegerField(nullable=False, default=1),
+        'min_node_count': fields.IntegerField(nullable=False, default=0),
         'is_default': fields.BooleanField(default=False),
         'stack_id': fields.StringField(nullable=True),
         'status': m_fields.ClusterStatusField(nullable=True),

magnum/tests/unit/api/controllers/test_root.py

@@ -41,7 +41,7 @@ class TestRootController(api_base.FunctionalTest):
                                [{u'href': u'http://localhost/v1/',
                                  u'rel': u'self'}],
                            u'status': u'CURRENT',
-                           u'max_version': u'1.9',
+                           u'max_version': u'1.10',
                            u'min_version': u'1.1'}]}
 
         self.v1_expected = {

magnum/tests/unit/api/controllers/v1/test_cluster.py

@@ -683,8 +683,7 @@ class TestPost(api_base.FunctionalTest):
         bdict['node_count'] = 0
         response = self.post_json('/clusters', bdict, expect_errors=True)
         self.assertEqual('application/json', response.content_type)
-        self.assertEqual(400, response.status_int)
-        self.assertTrue(response.json['errors'])
+        self.assertEqual(202, response.status_int)
 
     def test_create_cluster_with_node_count_negative(self):
         bdict = apiutils.cluster_post_data()

magnum/tests/unit/api/controllers/v1/test_nodegroup.py

@@ -40,7 +40,7 @@ class TestNodegroupObject(base.TestCase):
         del nodegroup_dict['max_node_count']
         nodegroup = api_nodegroup.NodeGroup(**nodegroup_dict)
         self.assertEqual(1, nodegroup.node_count)
-        self.assertEqual(1, nodegroup.min_node_count)
+        self.assertEqual(0, nodegroup.min_node_count)
         self.assertIsNone(nodegroup.max_node_count)
 
 
@@ -293,6 +293,20 @@ class TestPost(NodeGroupControllerTest):
         # Verify node_count defaults to 1
         self.assertEqual(1, response.json['node_count'])
 
+    @mock.patch('oslo_utils.timeutils.utcnow')
+    def test_create_nodegroup_with_zero_nodes(self, mock_utcnow):
+        ng_dict = apiutils.nodegroup_post_data()
+        ng_dict['node_count'] = 0
+        ng_dict['min_node_count'] = 0
+        test_time = datetime.datetime(2000, 1, 1, 0, 0)
+        mock_utcnow.return_value = test_time
+
+        response = self.post_json(self.url, ng_dict)
+        self.assertEqual('application/json', response.content_type)
+        self.assertEqual(202, response.status_int)
+        # Verify node_count is set to zero
+        self.assertEqual(0, response.json['node_count'])
+
     @mock.patch('oslo_utils.timeutils.utcnow')
     def test_create_nodegroup_with_max_node_count(self, mock_utcnow):
         ng_dict = apiutils.nodegroup_post_data(max_node_count=5)
@@ -366,7 +380,7 @@ class TestPost(NodeGroupControllerTest):
         self.assertEqual(self.cluster.project_id, response.json['project_id'])
         self.assertEqual(self.cluster.labels, response.json['labels'])
         self.assertEqual('worker', response.json['role'])
-        self.assertEqual(1, response.json['min_node_count'])
+        self.assertEqual(0, response.json['min_node_count'])
         self.assertEqual(1, response.json['node_count'])
         self.assertIsNone(response.json['max_node_count'])
 
@@ -662,7 +676,7 @@ class TestPatch(NodeGroupControllerTest):
 
         response = self.get_json(self.url + self.nodegroup.uuid)
         # Removing the min_node_count just restores the default value
-        self.assertEqual(1, response['min_node_count'])
+        self.assertEqual(0, response['min_node_count'])
         return_updated_at = timeutils.parse_isotime(
             response['updated_at']).replace(tzinfo=None)
         self.assertEqual(test_time, return_updated_at)

magnum/tests/unit/objects/test_objects.py

@@ -364,7 +364,7 @@ object_data = {
     'Stats': '1.0-73a1cd6e3c0294c932a66547faba216c',
     'Quota': '1.0-94e100aebfa88f7d8428e007f2049c18',
     'Federation': '1.0-166da281432b083f0e4b851336e12e20',
-    'NodeGroup': '1.0-8cb4544a28a49860d816158a7c3060b1'
+    'NodeGroup': '1.1-70211d19fcf53903a470607f1f4a784f'
 }
 
 

releasenotes/notes/allow-empty-node_groups-ec16898bfc82aec0.yaml

@@ -0,0 +1,7 @@
+---
+features:
+  - |
+    Clusters can now be created with empty nodegroups. Existing nodegroups
+    can be set to node_count = 0. min_node_count defaults to 0.
+    This is usefull for HA or special hardware clusters with multiple
+    nodegroups managed by the cluster auto-scaller.