Blackbox exporter

The blackbox exporter allows blackbox probing of endpoints over HTTP, HTTPS, DNS, TCP and ICMP.

Building and running

Local Build

make
./blackbox_exporter <flags>

Visiting http://localhost:9115/probe?target=google.com&module=http_2xx will return metrics for a HTTP probe against google.com. The probe_success metric indicates if the probe succeeded. Adding a debug=true parameter will return debug information for that probe.

Building with Docker

docker build -t blackbox_exporter .
docker run -d -p 9115:9115 --name blackbox_exporter -v `pwd`:/config blackbox_exporter --config.file=/config/blackbox.yml

Configuration

Blackbox exporter is configured via a configuration file and command-line flags (such as what configuration file to load, what port to listen on, and the logging format and level).

Blackbox exporter can reload its configuration file at runtime. If the new configuration is not well-formed, the changes will not be applied. A configuration reload is triggered by sending a SIGHUP to the Blackbox exporter process or by sending a HTTP POST request to the /-/reload endpoint.

To view all available command-line flags, run ./blackbox_exporter -h.

To specify which configuration file to load, use the --config.file flag.

Additionally, an example configuration is also available.

HTTP, HTTPS (via the http prober), DNS, TCP socket and ICMP (see permissions section) are currently supported. Additional modules can be defined to meet your needs.

The timeout of each probe is automatically determined from the scrape_timeout in the Prometheus config, slightly reduced to allow for network delays. This can be further limited by the timeout in the Blackbox exporter config file. If neither is specified, it defaults to 10 seconds.

Prometheus Configuration

The blackbox exporter needs to be passed the target as a parameter, this can be done with relabelling.

Example config:

scrape_configs:
  - job_name: 'blackbox'
    metrics_path: /probe
    params:
      module: [http_2xx]  # Look for a HTTP 200 response.
    static_configs:
      - targets:
        - http://prometheus.io    # Target to probe with http.
        - https://prometheus.io   # Target to probe with https.
        - http://example.com:8080 # Target to probe with http on port 8080.
    relabel_configs:
      - source_labels: [__address__]
        target_label: __param_target
      - source_labels: [__param_target]
        target_label: instance
      - target_label: __address__
        replacement: 127.0.0.1:9115  # Blackbox exporter.

Permissions

The ICMP probe requires elevated privileges to function:

• Windows: Administrator privileges are required.
• Linux: root user or CAP_NET_RAW capability is required.
  • Can be set by executing setcap cap_net_raw+ep blackbox_exporter
• BSD / OS X: root user is required.