Monitoring NGINX is crucial for ensuring the performance, reliability, and security of your web server. This section will cover various tools and techniques to monitor NGINX effectively.

1. Access Logs: Record all requests processed by NGINX.
2. Error Logs: Capture errors encountered by NGINX.
3. Stub Status Module: Provides basic status information about NGINX.
4. Third-Party Monitoring Tools: Tools like Prometheus, Grafana, and Datadog for advanced monitoring.

Access logs provide detailed information about every request processed by NGINX. This includes the client IP, request method, URI, response status, and more.

To enable access logging, add the following directive to your NGINX configuration file (nginx.conf):

• log_format main ...: Defines a custom log format named main.
• access_log /var/log/nginx/access.log main;: Specifies the log file and format.

Error logs capture any issues encountered by NGINX, such as configuration errors, server errors, and more.

To configure error logging, use the following directive in your nginx.conf:

• error_log /var/log/nginx/error.log warn;: Specifies the log file and the logging level (debug, info, notice, warn, error, crit, alert, emerg).

The Stub Status module provides basic status information about NGINX, such as active connections, requests per second, and more.

To enable the Stub Status module, add the following location block to your nginx.conf:

• location /nginx_status { ... }: Defines a location block for the status page.
• stub_status;: Enables the Stub Status module.
• allow 127.0.0.1;: Allows access from localhost.
• deny all;: Denies access from all other IPs.

You can access the status page by navigating to http://your_server_ip/nginx_status.

For advanced monitoring, you can integrate NGINX with third-party tools like Prometheus, Grafana, and Datadog.

Prometheus is an open-source monitoring and alerting toolkit, and Grafana is a visualization tool. Together, they provide a powerful monitoring solution.

Configuration

1. Install the NGINX Exporter: The NGINX Exporter exposes NGINX metrics in a format that Prometheus can scrape.

   docker run -d -p 9113:9113 nginx/nginx-prometheus-exporter:latest -nginx.scrape_uri=http://localhost:8080/nginx_status
   

2. Configure Prometheus: Add the NGINX Exporter as a scrape target in your prometheus.yml:

   scrape_configs:
     - job_name: 'nginx'
       static_configs:
         - targets: ['localhost:9113']
   

3. Visualize with Grafana: Add Prometheus as a data source in Grafana and create dashboards to visualize NGINX metrics.

Datadog is a cloud-based monitoring and analytics platform.

Configuration

1. Install the Datadog Agent: Follow the installation instructions for your operating system from the Datadog documentation.

2. Enable the NGINX Integration: Edit the nginx.d/conf.yaml file to enable the NGINX integration:

   init_config:
   
   instances:
     - nginx_status_url: http://localhost/nginx_status
       tags:
         - env:production
   

3. Restart the Datadog Agent:

   sudo systemctl restart datadog-agent
   

1. Objective: Enable the Stub Status module and access the status page.
2. Steps:
   • Add the location block for the Stub Status module to your nginx.conf.
   • Reload the NGINX configuration.
   • Access the status page from your browser.

1. Add the Location Block:

   server {
       location /nginx_status {
           stub_status;
           allow 127.0.0.1;
           deny all;
       }
   }
   

2. Reload NGINX:

   sudo nginx -s reload
   

3. Access the Status Page: Navigate to http://localhost/nginx_status.

In this section, we covered the basics of monitoring NGINX using access logs, error logs, the Stub Status module, and third-party tools like Prometheus, Grafana, and Datadog. Monitoring is essential for maintaining the health and performance of your NGINX server. In the next section, we will explore common issues and their solutions.