Nginx

This check parses the information provided by the NGINX stub status module. If you have enabled that module, then the URL /nginx_status shows interesting information about the inner state of the web server when accessed from localhost. The agent plugin nginx_status fetches these information and processes it.

Step-by-step guide

After installing and configuring nginx you can follow this steps to monitor Nginx status.

1. Nginx stub status module

   Make sure that the server process is configured with the stub status module. Use the command:

   root@klappanas:~# nginx -V 2>&1 | grep -o with-http_stub_status_module   
   with-http_stub_status_module

   If stub status module is not installed, you can follow this guide for the installation: https://www.tecmint.com/enable-nginx-status-page/

2. Add a new server block configuration inside /etc/nginx/sites-enabled/default

   /etc/nginx/sites-enabled/default

   server {
           listen 8081;
           listen [::]:8081;
   
           server_name _;
   
           root /var/www/html;
           index index.html;
   
           location /nginx_status
   {
                   stub_status on;
                   access_log off;
                   allow 127.0.0.1;
                   deny all;
   
           }
   }

3. restart nginx service

   systemctl restart nginx

4. Now the Url 127.0.0.1:8081/nginx_status should be available

   wget -qO - http://127.0.0.1:8081/nginx_status
   Active connections: 1 
   server accepts handled requests
    1 1 1 
   Reading: 0 Writing: 1 Waiting: 0 

5. Configure nginx_status

   1. manually
      you need to install the agent plugin nginx_status into your agent's plugins directory (usually /usr/lib/check_mk_agent/plugins). The plugin tries to autodetect all running NGINX servers. If that fails for some reason you need to create the configuration file /etc/check_mk/nginx_status.cfg. Here is one example:

      servers = [{'address': '127.0.0.1',
        'page': 'nginx_status',
        'port': 8081,
        'protocol': 'http'}]

   2. via Bakery
      WATO - CONFIGURATION → Monitoring Agents → Rules → NGINX webservers (Linux)

      1. Autodetect instances, expect HTTPS on the following ports: nginx_status will try autodetect all running NGINX servers.

         

      2. Specific list of instances: You can specify NGINX instances

         

6. Test the plugin

Now you can execute the plugin manually and see if it works:

MK_CONFDIR=/etc/check_mk /usr/lib/check_mk_agent/plugins/nginx_status 

<<<nginx_status>>>
127.0.0.1 8081 Active connections: 1 
127.0.0.1 8081 server accepts handled requests
127.0.0.1 8081  380 380 380 
127.0.0.1 8081 Reading: 0 Writing: 1 Waiting: 0 

Check_MK will create one service for each web server

Debugging

Port Checking

root@klappanas:~# netstat -tulpen |grep 8081
tcp        0      0 0.0.0.0:8081            0.0.0.0:*               LISTEN      0          43044      1353/nginx: master  
tcp6       0      0 :::8081                 :::*                    LISTEN      0          43045      1353/nginx: master  

Nginx Service

root@klappanas:~# systemctl status nginx

Stub status module

root@klappanas:~# nginx -V 2>&1 | grep -o with-http_stub_status_module   
with-http_stub_status_module

Checking the status page

root@klappanas:~# wget -qO - http://127.0.0.1:8081/nginx_status
Active connections: 1 
server accepts handled requests
 398 398 398 
Reading: 0 Writing: 1 Waiting: 0

Related articles

• Page:
  How-to enable Nginx status monitoring