Change to camelcase.

playbooks/roles/edxapp/defaults/main.yml

@@ -587,17 +587,17 @@ edxapp_generic_doc_store_config: &edxapp_generic_default_docstore
 edxapp_lms_draft_doc_store_config:
   <<: *edxapp_generic_default_docstore
   read_preference: "{{ EDXAPP_LMS_DRAFT_MONGO_READ_PREFERENCE }}"
-  replica_set: "{{ EDXAPP_LMS_DRAFT_MONGO_REPLICA_SET }}"
+  replicaSet: "{{ EDXAPP_LMS_DRAFT_MONGO_REPLICA_SET }}"
 
 edxapp_lms_split_doc_store_config:
   <<: *edxapp_generic_default_docstore
   read_preference: "{{ EDXAPP_LMS_SPLIT_MONGO_READ_PREFERENCE }}"
-  replica_set: "{{ EDXAPP_LMS_SPLIT_MONGO_REPLICA_SET }}"
+  replicaSet: "{{ EDXAPP_LMS_SPLIT_MONGO_REPLICA_SET }}"
 
 edxapp_cms_doc_store_config:
   <<: *edxapp_generic_default_docstore
   read_preference: "{{ EDXAPP_CMS_MONGO_READ_PREFERENCE }}"
-  replica_set: "{{ EDXAPP_CMS_MONGO_REPLICA_SET }}"
+  replicaSet: "{{ EDXAPP_CMS_MONGO_REPLICA_SET }}"
 
 edxapp_generic_auth_config:  &edxapp_generic_auth
   EVENT_TRACKING_SEGMENTIO_EMIT_WHITELIST: "{{ EDXAPP_EVENT_TRACKING_SEGMENTIO_EMIT_WHITELIST }}"