Define a default variable for default subnet.

cloudbridge/cloud/base/resources.py

@@ -816,6 +816,8 @@ class BaseSubnet(BaseCloudResource, BaseObjectLifeCycleMixin, Subnet):
 
     CB_DEFAULT_SUBNET_LABEL = os.environ.get('CB_DEFAULT_SUBNET_LABEL',
                                              'cloudbridge-subnet')
+    CB_DEFAULT_SUBNET_IPV4RANGE = os.environ.get('CB_DEFAULT_SUBNET_IPV4RANGE',
+                                                 '10.0.0.0/24')
 
     def __init__(self, provider):
         super(BaseSubnet, self).__init__(provider)

cloudbridge/cloud/base/services.py

@@ -223,8 +223,6 @@ class BaseSubnetService(
         return ClientPagedResultList(self._provider, list(matches))
 
     def get_or_create_default(self, zone):
-        default_cidr = '10.0.0.0/24'
-
         # Look for a CB-default subnet
         matches = self.find(label=BaseSubnet.CB_DEFAULT_SUBNET_LABEL)
         if matches:
@@ -233,7 +231,7 @@ class BaseSubnetService(
         # No provider-default Subnet exists, try to create it (net + subnets)
         network = self.provider.networking.networks.get_or_create_default()
         subnet = self.create(BaseSubnet.CB_DEFAULT_SUBNET_LABEL, network,
-                             default_cidr, zone)
+                             BaseSubnet.CB_DEFAULT_SUBNET_IPV4RANGE, zone)
         return subnet
 
 

cloudbridge/cloud/providers/aws/services.py

@@ -6,6 +6,8 @@ from botocore.exceptions import ClientError
 
 import cachetools
 
+import ipaddress
+
 import requests
 
 import cloudbridge.cloud.base.helpers as cb_helpers
@@ -867,12 +869,23 @@ class AWSSubnetService(BaseSubnetService):
         # Create a subnet in each of the region's zones
         region = self.provider.compute.regions.get(self.provider.region_name)
         default_sn = None
+
+        # Determine how many subnets we'll need for the default network and the
+        # number of available zones.
+        ip_net = ipaddress.ip_network(AWSNetwork.CB_DEFAULT_IPV4RANGE.decode())
+        for x in range(5):
+            if len(region.zones) <= len(list(ip_net.subnets(
+                    prefixlen_diff=x))):
+                prefixlen_diff = x
+                break
+        subnets = list(ip_net.subnets(prefixlen_diff=prefixlen_diff))
+
         for i, z in reversed(list(enumerate(region.zones))):
             sn_label = "{0}-{1}".format(AWSSubnet.CB_DEFAULT_SUBNET_LABEL,
                                         z.id[-1])
-            log.info("Creating default CloudBridge subnet %s", sn_label)
-            sn = self.create(
-                sn_label, default_net, '10.0.{0}.0/24'.format(i), z)
+            log.info("Creating a default CloudBridge subnet %s: %s" %
+                     (sn_label, str(subnets[i])))
+            sn = self.create(sn_label, default_net, str(subnets[i]), z)
             # Create a route table entry between the SN and the inet gateway
             # See note above about why this is commented
             # default_router.attach_subnet(sn)

cloudbridge/cloud/providers/openstack/services.py

@@ -876,7 +876,7 @@ class OpenStackSubnetService(BaseSubnetService):
             net = self.provider.networking.networks.get_or_create_default()
             sn = self.provider.networking.subnets.create(
                 label=OpenStackSubnet.CB_DEFAULT_SUBNET_LABEL,
-                cidr_block='10.0.0.0/24',
+                cidr_block=OpenStackSubnet.CB_DEFAULT_SUBNET_IPV4RANGE,
                 network=net)
             router = self.provider.networking.routers.get_or_create_default(
                 net)

docs/topics/setup.rst

@@ -212,24 +212,29 @@ In addition to the provider specific configuration variables above, there are
 some general configuration environment variables that apply to CloudBridge as
 a whole
 
-======================== ======================================================
-Variable		                            Description
-======================== ======================================================
-CB_DEBUG                 Setting ``CB_DEBUG=True`` will cause detailed debug
-                         output to be printed for each provider (including HTTP
-                         traces).
-CB_USE_MOCK_PROVIDERS    Setting this to ``True`` will cause the CloudBridge
-                         test suite to use mock drivers when available.
-CB_TEST_PROVIDER         Set this value to a valid :class:`.ProviderList` value
-                         such as ``aws``, to limit tests to that provider only.
-CB_DEFAULT_SUBNET_LABEL  Name to be used for a subnet that will be considered
-                         the 'default' by the library. This default will be
-                         used only in cases there is no subnet marked as the
-                         default by the provider.
-CB_DEFAULT_NETWORK_LABEL Name to be used for a network that will be considered
-                         the 'default' by the library. This default will be
-                         used only in cases there is no network marked as the
-                         default by the provider.
-CB_DEFAULT_IPV4RANGE     The default IPv4 range when creating networks if one
-                         is not provided. This value is also used in tests.
-======================== ======================================================
+=========================== ===================================================
+Variable                                    Description
+=========================== ===================================================
+CB_DEBUG                    Setting ``CB_DEBUG=True`` will cause detailed debug
+                            output to be printed for each provider (including
+                            HTTP traces).
+CB_USE_MOCK_PROVIDERS       Setting this to ``True`` will cause the CloudBridge
+                            test suite to use mock drivers when available.
+CB_TEST_PROVIDER            Set this value to a valid :class:`.ProviderList`
+                            value such as ``aws``, to limit tests to that
+                            provider only.
+CB_DEFAULT_SUBNET_LABEL     Name to be used for a subnet that will be
+                            considered the 'default' by the library. This
+                            default will be used only in cases there is no
+                            subnet marked as the default by the provider.
+CB_DEFAULT_NETWORK_LABEL    Name to be used for a network that will be
+                            considered the 'default' by the library. This
+                            default will be used only in cases there is no
+                            network marked as the default by the provider.
+CB_DEFAULT_IPV4RANGE        The default IPv4 range when creating networks if
+                            one is not provided. This value is also used in
+                            tests.
+CB_DEFAULT_SUBNET_IPV4RANGE The default subnet IPv4 range used by CloudBridge
+                            if one is not specified by the user. Tests do not
+                            respect this variable.
+=========================== ===================================================