Как настроить клиентов для передачи метрик в Prometheus?

To transmit metrics to Prometheus, exporters are used. Exporters are small services that open an HTTP endpoint containing metrics in a format understandable by Prometheus.

Main methods:

1. Using official and third-party exporters:

   • There are ready-made exporters for many popular services and systems: node_exporter (OS metrics), mysqld_exporter (MySQL metrics), kube-state-metrics (Kubernetes metrics), etc.
   • Setup involves installing the exporter on the target server and specifying its address in the Prometheus configuration.

2. Instrumenting applications:

   • Developers can add code to their applications to expose metrics directly.
   • The Prometheus project provides client libraries for various programming languages (Go, Java, Python, Ruby, etc.).
   • These libraries allow creating counters, gauges, histograms, and summaries, and then opening an HTTP endpoint for Prometheus to scrape.

3. Textfile Collector (for node_exporter):

   • node_exporter has a collector called textfile, which can read metrics from files in a specific format.
   • This is useful for periodic scripts or tasks that generate metrics.

4. Pushgateway:

   • Pushgateway is used for short-lived or batch jobs that cannot be scraped directly by Prometheus (as they might not exist at the time of scraping).
   • The application pushes its metrics to the Pushgateway, and Prometheus collects data from the Pushgateway.

# Example Prometheus configuration (prometheus.yml)
scrape_configs:
  - job_name: 'node_exporter_servers' # Scrape job name
    static_configs:
      - targets: ['server1:9100', 'server2:9100'] # List of hosts/ports where node_exporter is running

  - job_name: 'application_metrics' # Job for collecting application metrics
    metrics_path: /metrics # Path where the application exposes metrics
    static_configs:
      - targets: ['application-host:8080'] # Application address

  - job_name: 'pushgateway' # Job for collecting metrics from Pushgateway
    honor_labels: true # Important for correct label handling from Pushgateway
    static_configs:
      - targets: ['pushgateway-host:9091'] # Pushgateway address

After setting up exporters or instrumenting applications, Prometheus will periodically scrape the specified endpoints to collect metrics.