Set nginx fd limit according to nginx_worker_connections

roles/float-infra-nginx/defaults/main.yml

@@ -22,7 +22,7 @@ nginx_limit_perserver_rate: "100r/s"
 nginx_limit_perserver_burst: 100
 
 # Various top-level NGINX configuration options that might need tuning.
-nginx_worker_connections: 4096
+nginx_worker_connections: 8388608
 nginx_keepalive_timeout: "20s"
 nginx_server_names_hash_max_size: 2048
 nginx_server_names_hash_bucket_size: 2048
@@ -36,3 +36,4 @@ nginx_custom_error_pages: true
 # nginx_install_custom_error_pages: install float's custom error pages
 # in /var/www/html/__errors/.
 nginx_install_custom_error_pages: true
+

roles/float-infra-nginx/tasks/nginx.yml

@@ -67,8 +67,8 @@
     - proxy
 
 - name: Install NGINX systemd unit
-  copy:
-    src: nginx.service
+  template:
+    src: nginx.service.j2
     dest: /etc/systemd/system/nginx.service
   notify: reload nginx
 

roles/float-infra-nginx/files/nginx.service → roles/float-infra-nginx/templates/nginx.service.j2

@@ -18,7 +18,7 @@ ExecStop=/bin/kill -TERM $MAINPID
 
 User=nginx
 Group=nginx
-LimitNOFILE=65535
+LimitNOFILE={{ nginx_worker_connections * 2 }}
 
 NoNewPrivileges=yes
 PrivateTmp=yes