Prometheus Prometheus not scraping due to SSL issues

What is Prometheus Prometheus not scraping due to SSL issues

Understanding Prometheus and Its Purpose

Prometheus is an open-source systems monitoring and alerting toolkit originally built at SoundCloud. It is designed to collect metrics from configured targets at given intervals, evaluate rule expressions, display the results, and trigger alerts if some condition is observed to be true. Prometheus is a powerful tool for monitoring applications and infrastructure, providing insights into system performance and health.

Identifying the Symptom: SSL Scraping Issues

One common issue users encounter with Prometheus is the inability to scrape metrics from targets due to SSL issues. This symptom is typically observed when Prometheus fails to collect data from a target, and logs may show SSL-related errors such as certificate validation failures or handshake errors.

Common Error Messages

certificate signed by unknown authority SSL handshake failed unable to verify the first certificate

Exploring the Root Cause: SSL Certificate Errors

The root cause of SSL scraping issues in Prometheus often lies in SSL certificate errors or misconfigured SSL settings. Prometheus requires valid SSL certificates to establish secure connections with targets. If the certificates are invalid, expired, or not trusted by the Prometheus server, scraping will fail.

Potential Misconfigurations

Incorrect certificate paths in the Prometheus configuration. Expired or self-signed certificates not added to the trusted store. Misconfigured SSL settings in the target's server configuration.

Steps to Fix SSL Scraping Issues in Prometheus

To resolve SSL issues and ensure Prometheus can scrape metrics successfully, follow these steps:

1. Verify SSL Certificates

Ensure that the SSL certificates used by your targets are valid and not expired. You can use tools like SSL Checker to verify the certificate details.

2. Update Prometheus Configuration

Ensure that the tls_config section in your Prometheus configuration file (prometheus.yml) is correctly set up. Here is an example configuration:

scrape_configs: - job_name: 'example' static_configs: - targets: ['example.com:443'] tls_config: ca_file: '/etc/prometheus/certs/ca.crt' cert_file: '/etc/prometheus/certs/client.crt' key_file: '/etc/prometheus/certs/client.key'

3. Add Self-Signed Certificates to Trusted Store

If you are using self-signed certificates, add them to the trusted certificate store on the Prometheus server. This can be done by updating the CA certificates bundle or using the ca_file option in the tls_config.

4. Test the Connection

Use tools like curl to test the SSL connection from the Prometheus server to the target. This can help identify if the issue is with Prometheus or the target server:

curl -v --cacert /etc/prometheus/certs/ca.crt https://example.com:443/metrics

Conclusion

By ensuring that SSL certificates are valid and correctly configured, you can resolve SSL scraping issues in Prometheus. Regularly updating certificates and verifying configurations will help maintain a secure and efficient monitoring setup. For more information on Prometheus configuration, refer to the official documentation.