Prometheus Blackbox Exporter works by executing probes against endpoints and returning metrics based on the results of those probes. For example, the HTTP probe supports various options, such as setting a custom user agent string, specifying custom headers, and setting a timeout for the request. The exporter also supports authentication options for HTTP and HTTPS probes, allowing you to specify credentials for basic authentication or a bearer token for token-based authentication. It also provides several advanced features, such as caching probe results, configuring timeouts, and retries for probes. These features help ensure the exporter is efficient and reliable, even in complex and dynamic environments.

Metrics

Prometheus Blackbox Exporter can collect a wide range of metrics to monitor the availability and performance of networked services. Some of the commonly used metrics that Prometheus Blackbox Exporter can collect include:

  1. Uptime

This metric measures the availability and uptime of a service or system. It provides information on how long the service has been up and running without experiencing any downtime.

  2. Latency:

Latency is a critical metric that measures the time taken for a service to respond to a request. Prometheus Blackbox Exporter can measure the latency of a service by sending requests and measuring the response time, helping to identify any performance degradation or delays.

  3. Response Codes:

Prometheus Blackbox Exporter can collect HTTP response codes, such as 200 OK, 404 Not Found and 500 Internal Server Error, to provide information on the status of the service or system being probed. This can help detect any issues or errors in the service's responses.

  4. DNS Resolution Time: 

Prometheus Blackbox Exporter can measure the time taken to resolve DNS queries, providing insights into the performance of DNS resolution for a given service or system.

  5. SSL/TLS Handshake Time:

If the probed service uses SSL/TLS encryption, Prometheus Blackbox Exporter can measure the time taken for the SSL/TLS handshake, providing information on the performance and security of the encryption process.

  6. Network Connectivity: 

Prometheus Blackbox Exporter can monitor network connectivity by checking if a service is reachable and providing information on network availability and potential connectivity issues.

  7. Content Validation: 

Prometheus Blackbox Exporter can validate the content of a response from a service to ensure that it matches expected patterns or values, verifying the correctness of responses from a service.

  8. Custom Metrics: 

Prometheus Blackbox Exporter also supports custom metrics besides the built-in metrics. Users can define their metrics based on their specific monitoring requirements, allowing for flexibility in monitoring and alerting.

The exact metrics that can be collected in any specific implementation depend on the configuration and probing parameters set up for each target. By collecting and analyzing these metrics, Prometheus Blackbox Exporter provides valuable insights into networked services' health and performance, helping to identify and resolve issues proactively.