modify rate limiting

playbooks/roles/edxapp/defaults/main.yml

@@ -225,9 +225,9 @@ EDXAPP_CMS_NGINX_PORT: 18010
 EDXAPP_CMS_SSL_NGINX_PORT: 48010
 
 # NGINX Rate limiting related vars
-EDXAPP_ENABLE_RATE_LIMITING: false
+EDXAPP_ENABLE_RATE_LIMITING: true
 EDXAPP_COURSE_REQUEST_RATE: '5r/s'
-EDXAPP_COURSE_REQUEST_BURST_RATE: 10
+EDXAPP_COURSE_REQUEST_BURST_RATE: 0
 
 EDXAPP_LANG: 'en_US.UTF-8'
 EDXAPP_LANGUAGE_CODE : 'en'

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

@@ -13,7 +13,7 @@ upstream lms-backend {
 
 {%- if EDXAPP_ENABLE_RATE_LIMITING -%}
 # Make Zone
-limit_req_zone $cookie_{{ EDXAPP_SESSION_COOKIE_NAME }} zone=cookies:10m rate={{ EDXAPP_COURSES_REQUEST_RATE }};
+limit_req_zone $cookie_{{ EDXAPP_SESSION_COOKIE_NAME }} zone=cookies:10m rate=12r/m;
 {%- endif %}
 
 
@@ -198,7 +198,7 @@ error_page {{ k }} {{ v }};
   location /courses {
     {%- if EDXAPP_ENABLE_RATE_LIMITING -%}
     # Set Limit
-    limit_req zone=cookies burst={{ EDXAPP_COURSE_REQUEST_BURST_RATE }};
+    limit_req zone=cookies;
     error_page  503 = /server/rate-limit.html;
     {%- endif -%}