Could you explain the Auto Discovery principle in the Prometheus monitoring system?

Auto Discovery in Prometheus is a mechanism for automatically detecting monitoring targets without the need to manually specify them in the configuration. Prometheus supports various autodiscovery methods, such as through the Kubernetes API, Consul, EC2, Docker, and other services.

Working principle:

• Prometheus periodically polls the specified source (e.g., Kubernetes API) to obtain a list of active services or containers.
• Based on the received data, a list of targets for metric collection is formed.
• This allows for dynamic adaptation of monitoring when infrastructure changes, such as scaling or updating services.

Example configuration for Kubernetes:

scrape_configs:
  - job_name: 'kubernetes-pods'
    kubernetes_sd_configs:
      - role: pod

Here, Prometheus will automatically discover all pods in the cluster and start collecting metrics from them if they export metrics on the standard port.