un-hardcode default subnet az

allow defining 'default_az' for one of the subnets in the vpc structure, and pull that default_az and set it to openshift_aws_subnet_az.

this should allow one less variable to have to be defined/overridded (openshift_aws_subnet_az) when using non-default (us-east-1) regions

update provisioning_vars.yml.example to show an example VPC structure

1 files changed, 16 insertions, 0 deletions

diff --git a/roles/lib_utils/filter_plugins/openshift_aws_filters.py b/roles/lib_utils/filter_plugins/openshift_aws_filters.py
index dfcb11da3..f16048056 100644
--- a/roles/lib_utils/filter_plugins/openshift_aws_filters.py
+++ b/roles/lib_utils/filter_plugins/openshift_aws_filters.py
@@ -67,8 +67,24 @@ class FilterModule(object):
 
         return tags
 
+    @staticmethod
+    def get_default_az(subnets):
+        ''' From a list of subnets/AZs in a specific region (from the VPC
+            structure), return the AZ that has the key/value
+            'default_az=True.' '''
+
+        for subnet in subnets:
+            if subnet.get('default_az'):
+                return subnet['az']
+
+        # if there was none marked with default_az=True, just return the first
+        # one. (this does mean we could possible return an item that has
+        # default_az=False set
+        return subnets[0]['az']
+
     def filters(self):
         ''' returns a mapping of filters to methods '''
         return {'build_instance_tags': self.build_instance_tags,
+                'get_default_az': self.get_default_az,
                 'scale_groups_match_capacity': self.scale_groups_match_capacity,
                 'scale_groups_serial': self.scale_groups_serial}