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Spring Boot Actuator

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Overview

Spring Boot Actuator is a module that provides built-in production-ready features for monitoring and managing a Spring Boot application, such as health checks, metrics, and endpoint exposure, enabling easier operational insight and management.

Settings

  • Add dependencies Spring Web, Spring Boot Actuator in spring initializr
  • gradle
    • implementation 'org.springframework.boot:spring-boot-starter-actuator'

Default Endpoints

  • /actuator
  • /actuator/health
    • reports the system’s health status
    • UP means the system is operating normally, and DOWN indicates an abnormal or unhealthy state
  • /actuator/metrics: offers metrics like memory usage, CPU load, request throughput, and more

Exposing more endpoints

  • By default, Spring Boot Actuator exposes all endpoints via JMX (Java Management Extensions), but only the health and info endpoints are enabled over HTTP.
  • To expose more endpoints through HTTP, you need to configure this explicitly in your application.properties or application.yml file.
management:
  endpoints:
    web:
      exposure:
        include: '*'
        exclude: ''
  • management.endpoints.web.exposure.include: '*'
    • This means expose all actuator endpoints over HTTP.
    • The wildcard '*' includes every endpoint (like /health, /metrics, /info, /beans, /env, etc.).
  • management.endpoints.web.exposure.exclude: ''
    • This means exclude no endpoints (empty string).
    • So nothing is excluded from exposure.

Exposing specific endpoints

management:
  endpoint:
    shutdown:
      enabled: true
  • Enables the /actuator/shutdown endpoint.
    • This endpoint allows you to programmatically shut down the Spring Boot application via HTTP.
    • Only works if your app is running as a standalone JAR (not in embedded servlet containers or some cloud environments).

Health endpoint

management:
  endpoint:
    health:
      # controls how much detail the `/health` endpoint reveals** in its response
      show-details: always 
  endpoints:
    web:
      exposure:
        include: "*"
  • Health endpoint is enabled by default
    • To make sure the health endpoint is available → set enabled: true
  • To control the detail level of the info it exposes → set show-details: always (or other options).
  • In addition to the default health information, you can enable individual health checks for components like DB, ping, Cassandra, Redis, and others.
# actuator  
management:  
  endpoints:  
    web:  
      exposure:  
        include: "health,info,metrics,loggers"  
  endpoint:  
    health:  
      show-details: always
  • management: This is the main prefix for all Spring Boot Actuator settings. It tells Spring, “All the settings indented under this key are for managing the application.”
  • endpoints.web.exposure.include: This is the most critical part for making endpoints accessible over HTTP.
    • endpoints: Configures Actuator endpoints in general.
    • web: Specifies that this configuration is for web access (i.e., through a browser or an API call).
    • exposure: Controls which endpoints are exposed.
    • include: "health,info,metrics,loggers": This is an explicit “whitelist.” You are telling Spring Boot, “Only expose these four endpoints over the web. Keep all others hidden.”
  • endpoint.health.show-details: always This configures a specific property for a single endpoint.
    • endpoint: The prefix for configuring individual endpoints.
    • health: You are targeting the health endpoint specifically.
    • show-details: always: By default, the health endpoint might only show a simple status like {"status":"UP"}. Setting this to always tells it to include detailed information from all health checks (e.g., disk space, database connectivity, etc.).

info

  • Anything you define under the info key is automatically exposed by the /actuator/info endpoint.
  • It’s a simple and direct way to publish custom, static information about your application. When you make a GET request to http://localhost:8080/actuator/info, Spring will take the YAML structure you wrote, convert it to JSON, and display it.
# anything you define under the info key is automatically exposed by the /actuator/info endpoint  
info:  
  app:  
    name: "Discodeit"  
    version: "1.7.0"  
    java: "17"  
    spring-boot: "3.4.0"  
    config:  
      datasource:  
        url: jdbc:postgresql://localhost:5432/discodeit  
        driver-class-name: org.postgresql.Driver  
        jpa:  
          hibernate:  
            ddl-auto: update  
        storage:  
          type: "local" # Example value  
          path: "/uploads/files" # Example value  
        multipart:  
          max-file-size: "10MB" # Example value  
          max-request-size: "15MB" # Example value

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