role parameters for ec2 launch role

playbooks/edx-east/edx_provision.yml

-- name: Create sandbox instance
+- name: Create ec2 instance
   hosts: localhost
   connection: local
   gather_facts: False
-  vars:
-    keypair: continuous-integration
-    instance_type: m1.small
-    security_group: sandbox
-    image: ami-d0f89fb9
-    region: us-east-1
-    instance_tags: '{"disposable": "true"}'
-    size: 50
   roles:
-    - launch_instance
+    - role: launch_instance
+      keypair: {{ keypair }}
+      instance_type: {{ instance_type }}
+      security_group: {{ security_group }}
+      ami_image: {{ ami }}
+      region: {{ region }}
+      instance_tags: {{ instance_tags }}
+      size: {{ size }}
+
 
 - name: Configure instance(s)
   hosts: launched

playbooks/roles/launch_instance/defaults/main.yml → playbooks/roles/launch_ec2/defaults/main.yml

 ---
-instance_tags: '{"from_ansible": "true"}'

playbooks/roles/launch_instance/tasks/main.yml → playbooks/roles/launch_ec2/tasks/main.yml

 # Launches an ec2 instance and blocks until the instance is up
 # adds it to the host group 
 
-- name: launch_instance | Launch instance 
+- name: launch_ec2 | Launch ec2 instance 
   local_action: 
     module: ec2 
-    keypair: "{{keypair}}"
-    group: "{{security_group}}"
-    instance_type: "{{instance_type}}"
-    image: "{{image}}"
+    keypair: "{{ keypair }}"
+    group: "{{ security_group }}"
+    instance_type: "{{ instance_type }}"
+    image: "{{ ami }}"
     wait: true 
-    region: "{{region}}"
+    region: "{{ region }}"
     instance_tags: "{{instance_tags}}"
   register: ec2