var updates

playbooks/roles/edxapp/defaults/main.yml

@@ -37,6 +37,11 @@ EDXAPP_MYSQL_PASSWORD: 'password'
 EDXAPP_MYSQL_PASSWORD_READ_ONLY: 'password'
 EDXAPP_MYSQL_PASSWORD_ADMIN: 'password'
 EDXAPP_MYSQL_PASSWORD_MIGRATE: 'password'
+EDXAPP_MYSQL_REPLICA_DB_NAME: "{{ EDXAPP_MYSQL_DB_NAME }}"
+EDXAPP_MYSQL_REPLICA_USER: "{{ EDXAPP_MYSQL_USER }}"
+EDXAPP_MYSQL_REPLICA_PASSWORD: "{{ EDXAPP_MYSQL_PASSWORD }}"
+EDXAPP_MYSQL_REPLICA_HOST: "{{ EDXAPP_MYSQL_HOST }}"
+EDXAPP_MYSQL_REPLICA_PORT: "{{ EDXAPP_MYSQL_PORT }}"
 
 EDXAPP_MYSQL_HOST: 'localhost'
 EDXAPP_MYSQL_PORT: '3306'
@@ -360,6 +365,13 @@ edxapp_generic_auth_config:  &edxapp_generic_auth
       OPTIONS:  *generic_modulestore_default_options
       DOC_STORE_CONFIG: *edxapp_generic_default_docstore
   DATABASES:
+    read_replica:
+      ENGINE: 'django.db.backends.mysql'
+      NAME: $EDXAPP_MYSQL_REPLICA_DB_NAME
+      USER: $EDXAPP_MYSQL_REPLICA_USER
+      PASSWORD: $EDXAPP_MYSQL_REPLICA_PASSWORD
+      HOST: $EDXAPP_MYSQL_REPLICA_HOST
+      PORT: $EDXAPP_MYSQL_REPLICA_PORT
     default:
       ENGINE: 'django.db.backends.mysql'
       NAME: $EDXAPP_MYSQL_DB_NAME