Spring Actuator

How to collect basic data from Spring into Prometheus

Enabling Actuator in Spring

Add the following to your main program's Maven configuration:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

<!-- Note the registry version should be compatible with your Spring Boot version, otherwise registration may fail -->
<dependency>
    <groupId>io.micrometer</groupId>
    <artifactId>micrometer-registry-prometheus</artifactId>
</dependency>

This will automatically expose the corresponding metrics. If you need the Java program to actively push monitoring data, additional configuration is required:

<dependency>
	<groupId>io.prometheus</groupId>
	<artifactId>prometheus-metrics-exporter-pushgateway</artifactId>
</dependency>

Access Control Exemption

In Spring, you need to configure the properties version:

management.endpoints.web.exposure.include=prometheus

For YAML, configure:

management:
  endpoints:
    web:
      exposure:
        include: prometheus

If you have authentication rules, avoid being intercepted by access control. Please exempt /actuator/prometheus data access.

Accessing Prometheus Data Endpoints in Spring

# View all HTTP request metrics
curl http://localhost:8080/actuator/metrics/http.server.requests

# View the duration of a specific API
curl "http://localhost:8080/actuator/metrics/http.server.requests?tag=uri:/api/agvLocation/query.json"

Prometheus Collection Configuration

- job_name: 'springboot-app1'
  metrics_path: '/actuator/prometheus'
  scrape_interval: 30s
  static_configs:
    - targets:
        - '127.0.0.1:8080'
      labels:
        app: 'springboot-app1'
        env: 'prod'

Grafana Monitoring Dashboard Template

https://grafana.com/grafana/dashboards/4701-jvm-micrometer/

Core Metric Explanations

In general, we focus on http_xxx metrics as they are closely related to users.

1. JVM Related Metrics

• jvm_memory_used_bytes
  JVM memory used in bytes, helping monitor memory consumption and memory leak risks.

• jvm_memory_max_bytes
  Maximum memory that JVM can allocate, monitoring whether it's approaching the memory limit.

• jvm_threads_live
  Current number of live threads, monitoring thread leaks and blocking issues.

• jvm_gc_pause_seconds_count / sum
  GC pause count and total duration, evaluating the impact of garbage collection on application performance.

2. System Resource Metrics

• process_cpu_usage
  CPU usage of the application process, reflecting application load.

• process_uptime_seconds
  Application uptime, determining if the service is restarting frequently.

• system_cpu_usage
  Overall CPU usage of the host or container.

3. HTTP Request Related Metrics

• http_server_requests_seconds_count
  Total number of HTTP requests, reflecting business traffic.

• http_server_requests_seconds_sum
  Total request duration, combined with count to calculate average response time.

• http_server_requests_seconds_max
  Maximum request duration, monitoring slow interfaces.

• http_server_requests_active
  Number of requests currently being processed, judging interface pressure.

4. Database Connection Pool Metrics (using HikariCP as an example)

• hikaricp_connections_active
  Current number of active database connections.

• hikaricp_connections_max
  Maximum available database connections.

• hikaricp_connections_pending
  Number of requests waiting to acquire database connections, reflecting database pressure.

5. Tomcat Related Metrics (if using Tomcat)

• tomcat_threads_current
  Current number of Tomcat threads.

• tomcat_threads_busy
  Current number of busy threads.

• tomcat_sessions_active_current
  Current number of active sessions.

References

• Spring Boot Manual (Please refer to your Spring Boot version)