ref(contrib/ec2): make ELB scheme a template parameter

Author: carmstrong

contrib/ec2/deis.template.json

@@ -91,6 +91,13 @@
       "Default": "true",
       "AllowedValues" : [ "true", "false" ],
       "ConstraintDescription" : "must be either true or false"
+    },
+    "ELBScheme": {
+      "Description": "Whether to create an internal-only load balancer, or a public-facing one (default)",
+      "Type": "String",
+      "Default": "internet-facing",
+      "AllowedValues" : [ "internet-facing", "internal" ],
+      "ConstraintDescription" : "must be either 'internet-facing' for public use, or 'internal' for private use"
     }
   },
 
@@ -271,7 +278,7 @@
       "Type": "AWS::ElasticLoadBalancing::LoadBalancer",
       "DependsOn" : "GatewayToInternet",
       "Properties": {
-        "Scheme" : "internet-facing",
+        "Scheme" : {"Ref": "ELBScheme"},
         "HealthCheck": {
           "HealthyThreshold": "4",
           "Interval": "15",

contrib/ec2/gen-json.py

@@ -90,11 +90,6 @@
 VPC_ID = os.getenv('VPC_ID', None)
 VPC_SUBNETS = os.getenv('VPC_SUBNETS', None)
 VPC_ZONES = os.getenv('VPC_ZONES', None)
-ELB_SCHEME = os.getenv('ELB_SCHEME', None)
-
-if ELB_SCHEME:
-  # Update ELB Scheme
-  template['Resources']['DeisWebELB']['Properties']['Scheme'] = ELB_SCHEME
 
 if VPC_ID and VPC_SUBNETS and VPC_ZONES and len(VPC_SUBNETS.split(',')) == len(VPC_ZONES.split(',')):
   # skip VPC, subnet, route, and internet gateway creation

docs/installing_deis/aws.rst

@@ -80,7 +80,7 @@ Customize cloudformation.json
 -----------------------------
 
 Any of the parameter defaults defined in deis.template.json can be overridden by setting the value
-in `cloudformation.json`_ like so:
+in `cloudformation.json`_. For example, to configure all of the optional settings:
 
 .. code-block:: console
 
@@ -99,8 +99,13 @@ in `cloudformation.json`_ like so:
     {
         "ParameterKey":     "AssociatePublicIP",
         "ParameterValue":   "false"
+    },
+    {
+        "ParameterKey":     "ELBScheme",
+        "ParameterValue":   "internal"
     }
 
+
 The only entry in cloudformation.json required to launch your cluster is `KeyPair`, which is
 already filled out. The defaults will be applied for the other settings.
 
@@ -135,15 +140,6 @@ For example, if your VPC has ID ``vpc-a26218bf`` and consists of the subnets ``s
     export VPC_SUBNETS=subnet-04d7f942,subnet-2b03ab7f
     export VPC_ZONES=us-east-1b,us-east-1c
 
-Change ELB Scheme
-------------------------
-For load balancers attached to an Amazon VPC, this parameter can be used to specify the type of load balancer to use. 
-Specify internal to create an internal load balancer with a DNS name that resolves to private IP addresses or 
-internet-facing to create a load balancer with a publicly resolvable DNS name, which resolves to public IP addresses.
-
-.. code-block:: console
-
-    export ELB_SCHEME=internet-facing|internal
 
 Run the Provision Script
 ------------------------
@@ -184,15 +180,15 @@ start installing the platform.
 CloudFormation Updates
 ----------------------
 
-To use CloudFormation to perform update operations to your stack, there is another script: 
+To use CloudFormation to perform update operations to your stack, there is another script:
 `update_ec2_cluster.sh`_. Depending on the parameters that you have changed, CloudFormation
 may replace the EC2 instances in your stack.
 
 The following parameters can be changed without replacing all instances in a stack:
 
 - ``ClusterSize`` - Number of nodes in the cluster. This may launch new instances or terminate
   existing instances. If you are scaling down, this may interrupt service. If a container
-  was running on an instance that was terminated, it will have to be rebalanced onto another 
+  was running on an instance that was terminated, it will have to be rebalanced onto another
   node which will cause some downtime.
 - ``SSHFrom`` - Locks down SSH access to the Deis hosts. This will update the security
   group for the Deis hosts.