Externalize the rate limiting settings to vars.

playbooks/roles/edxapp/defaults/main.yml

@@ -144,6 +144,11 @@ EDXAPP_LMS_PREVIEW_NGINX_PORT: 18020
 EDXAPP_CMS_NGINX_PORT: 18010
 EDXAPP_CMS_SSL_NGINX_PORT: 48010
 
+# NGINX Rate limiting related vars
+EDXAPP_ENABLE_RATE_LIMITING: true
+EDXAPP_COURSE_REQUEST_RATE: '5r/s'
+EDXAPP_COURSE_REQUEST_BURST_RATE: 10
+
 EDXAPP_LANG: 'en_US.UTF-8'
 EDXAPP_LANGUAGE_CODE : 'en'
 EDXAPP_TIME_ZONE: 'America/New_York'

playbooks/roles/nginx/templates/edx/app/nginx/sites-available/lms.j2

@@ -10,8 +10,10 @@ upstream lms-backend {
     {% endfor %}
 }
 
+{%- if EDXAPP_ENABLE_RATE_LIMITING -%}
 # Make Zone
-limit_req_zone $cookie_{{ EDXAPP_SESSION_COOKIE_NAME }} zone=cookies:10m rate=1r/s;
+limit_req_zone $cookie_{{ EDXAPP_SESSION_COOKIE_NAME }} zone=cookies:10m rate={{ EDXAPP_COURSES_REQUEST_RATE }};
+{%- endif -%}
 
 server {
   # LMS configuration file for nginx, templated by ansible
@@ -72,9 +74,12 @@ server {
   }
 
   location /courses {
+    {%- if EDXAPP_ENABLE_RATE_LIMITING -%}
     # Set Limit  
-    limit_req zone=cookies burst=3;
-    {% include "basic-auth.j2" %}
+    limit_req zone=cookies burst={{ EDXAPP_COURSE_REQUEST_BURST_RATE }};
+    {%- endif -%}
+
+    {%- include "basic-auth.j2" %}
     try_files $uri @proxy_to_lms_app;
   }