What are the differences between Prometheus Pull and Push modes, and how to choose?

Prometheus uses the Pull model for data collection but also supports the Push model:

Pull Model (Recommended):

• Prometheus actively pulls metrics from targets
• Advantages:
  • Simple architecture, easy to scale
  • Automatic target discovery via service discovery
  • Supports target health checks
  • Reduces complexity of target services
• Use Cases:
  • Long-running services
  • Containerized environments
  • Kubernetes clusters

Push Model:

• Targets actively push metrics to Pushgateway
• Advantages:
  • Suitable for short-lived jobs
  • No need for targets to expose HTTP ports
• Disadvantages:
  • Cannot monitor target health status
  • Pushgateway becomes a single point of failure
  • Data may become stale
• Use Cases:
  • Batch processing jobs
  • Temporary tasks
  • Short-running jobs

Service Discovery Mechanisms:

• Static configuration
• Kubernetes API
• DNS SRV records
• Consul
• Cloud platforms like EC2, Azure

Configuration Example:

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

Best Practices:

• Prioritize the Pull model
• Use Pushgateway for short-lived jobs
• Set reasonable scrape intervals (typically 15s-1m)