Support ram limit per pool

Nodepool supports pretty generic limits on tenant and pool side. Make
the ram limit configurable.

Change-Id: Ie9f1ece75106fa936a737ed2b289188d9a594fb0

doc/source/configuration.rst

@@ -432,6 +432,11 @@ Example::
     limit the number of servers. If not defined nodepool can create as many
     servers the tenant allows.
 
+  ``max-ram``
+    Maximum ram usable from this pool. This can be used to limit the amount of
+    ram allocated by nodepool. If not defined nodepool can use as much ram as
+    the tenant allows.
+
   ``availability-zones`` (list)
     A list of availability zones to use.
 

nodepool/driver/openstack/config.py

@@ -63,6 +63,7 @@ class ProviderPool(ConfigValue):
         if (other.labels != self.labels or
             other.max_cores != self.max_cores or
             other.max_servers != self.max_servers or
+            other.max_ram != self.max_ram or
             other.azs != self.azs or
             other.networks != self.networks):
             return False
@@ -159,6 +160,7 @@ class OpenStackProviderConfig(ProviderConfig):
             self.pools[pp.name] = pp
             pp.max_cores = pool.get('max-cores', None)
             pp.max_servers = pool.get('max-servers', None)
+            pp.max_ram = pool.get('max-ram', None)
             pp.azs = pool.get('availability-zones')
             pp.networks = pool.get('networks', [])
             pp.auto_floating_ip = bool(pool.get('auto-floating-ip', True))
@@ -242,6 +244,7 @@ class OpenStackProviderConfig(ProviderConfig):
             'auto-floating-ip': bool,
             'max-cores': int,
             'max-servers': int,
+            'max-ram': int,
             'labels': [pool_label],
             'availability-zones': [str],
         }

nodepool/driver/openstack/handler.py

@@ -356,6 +356,7 @@ class OpenStackNodeRequestHandler(NodeRequestHandler):
         # to math.inf representing infinity that can be calculated with.
         pool_quota = QuotaInformation(cores=self.pool.max_cores,
                                       instances=self.pool.max_servers,
+                                      ram=self.pool.max_ram,
                                       default=math.inf)
         pool_quota.subtract(
             self.manager.estimatedNodepoolQuotaUsed(self.zk, self.pool))
@@ -388,6 +389,7 @@ class OpenStackNodeRequestHandler(NodeRequestHandler):
         # to math.inf representing infinity that can be calculated with.
         pool_quota = QuotaInformation(cores=self.pool.max_cores,
                                       instances=self.pool.max_servers,
+                                      ram=self.pool.max_ram,
                                       default=math.inf)
         pool_quota.subtract(needed_quota)
         return pool_quota.non_negative()

nodepool/tests/fixtures/node_quota_pool_ram.yaml

@@ -0,0 +1,39 @@
+elements-dir: .
+images-dir: '{images_dir}'
+
+zookeeper-servers:
+  - host: {zookeeper_host}
+    port: {zookeeper_port}
+    chroot: {zookeeper_chroot}
+
+labels:
+  - name: fake-label
+    min-ready: 0
+
+providers:
+  - name: fake-provider
+    cloud: fake
+    driver: fake
+    region-name: fake-region
+    rate: 0.0001
+    diskimages:
+      - name: fake-image
+    pools:
+      - name: main
+        max-ram: 16384
+        labels:
+          - name: fake-label
+            diskimage: fake-image
+            min-ram: 8192
+
+diskimages:
+  - name: fake-image
+    elements:
+      - fedora
+      - vm
+    release: 21
+    env-vars:
+      TMPDIR: /opt/dib_tmp
+      DIB_IMAGE_CACHE: /opt/dib_cache
+      DIB_CLOUD_IMAGES: http://download.fedoraproject.org/pub/fedora/linux/releases/test/21-Beta/Cloud/Images/x86_64/
+      BASE_IMAGE_FILE: Fedora-Cloud-Base-20141029-21_Beta.x86_64.qcow2

nodepool/tests/test_launcher.py

@@ -233,6 +233,9 @@ class TestLauncher(tests.DBTestCase):
         self._test_node_assignment_at_quota(
             config='node_quota_pool_instances.yaml')
 
+    def test_node_assignment_at_pool_quota_ram(self):
+        self._test_node_assignment_at_quota(
+            config='node_quota_pool_ram.yaml')
 
     def test_node_assignment_at_cloud_cores_quota(self):
         self._test_node_assignment_at_quota(config='node_quota_cloud.yaml',