DB_ADMIN is not a dict.

playbooks/roles/course_discovery/tasks/main.yml

@@ -84,8 +84,8 @@
 - name: create databases
   mysql_db:
     login_host: "{{ COURSE_DISCOVERY_DATABASES.default.HOST }}"
-    login_user: "{{ COURSE_DISCOVERY_DB_ADMIN.default.USER }}"
-    login_password: "{{ COURSE_DISCOVERY_DB_ADMIN.default.PASSWORD }}"
+    login_user: "{{ COURSE_DISCOVERY_DB_ADMIN_USER }}"
+    login_password: "{{ COURSE_DISCOVERY_DB_ADMIN_PASSWORD }}"
     db: "{{ COURSE_DISCOVERY_DEFAULT_DB_NAME }}"
     state: present
     encoding: utf8
@@ -95,8 +95,8 @@
 - name: create database users
   mysql_user:
     login_host: "{{ COURSE_DISCOVERY_DATABASES.default.HOST }}"
-    login_user: "{{ COURSE_DISCOVERY_DB_ADMIN.default.USER }}"
-    login_password: "{{ COURSE_DISCOVERY_DB_ADMIN.default.PASSWORD }}"
+    login_user: "{{ COURSE_DISCOVERY_DB_ADMIN_USER }}"
+    login_password: "{{ COURSE_DISCOVERY_DB_ADMIN_PASSWORD }}"
     name: "{{ item.name }}"
     host: "%"
     name: "{{ item.password }}"