| 1 | ### Understand the alert |
| 2 | |
| 3 | This alert is triggered when the percentage of successful HTTP requests (1xx, 2xx, 304, 401 response codes) within the last minute falls below a certain threshold. A warning state occurs when the success rate is below 85%, and a critical state occurs when it falls below 75%. This alert can indicate a malfunction in your web server's services, malicious activity towards your website, or broken links. |
| 4 | |
| 5 | ### Troubleshoot the alert |
| 6 | |
| 7 | 1. **Analyze response codes**: Identify the specific HTTP response codes your web server is sending to clients. Use the Netdata dashboard and inspect the `detailed_response_codes` chart for your web server to track the error codes being sent. |
| 8 | |
| 9 | 2. **Check server logs**: Review the web server logs to identify any issues, patterns, or errors causing the decrease in successful requests. Investigate any unusual or unexpected response codes. |
| 10 | |
| 11 | 3. **Inspect application logs**: Check the logs of applications running on your web server for any errors or issues that might be affecting the success rate of HTTP requests. |
| 12 | |
| 13 | 4. **Verify server resources**: Ensure your server has adequate resources (CPU, RAM, disk space) to handle the workload, as resource limitations can impact the success rate of HTTP requests. |
| 14 | |
| 15 | 5. **Review server configuration**: Check your web server's configuration for any misconfigurations, incorrect permissions, or improper settings that may be causing the issue. |
| 16 | |
| 17 | 6. **Monitor security**: Look for signs of malicious activity, such as a high number of requests from a specific IP address or a sudden spike in requests. Implement security measures, such as rate limiting, IP blocking, or Web Application Firewalls (WAF), if necessary. |
| 18 | |
| 19 | ### Useful resources |
| 20 | |
| 21 | 1. [HTTP status codes on Mozilla](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status) |
| 22 | 2. [Apache HTTP Server Documentation](https://httpd.apache.org/docs/) |
| 23 | 3. [Nginx Documentation](https://nginx.org/en/docs/) |