Spring Boot Actuator

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

// Gradle
dependencies {
    implementation "org.springframework.boot:spring-boot-starter-actuator"
}

After adding the dependency, verify endpoints respond:

curl http://localhost:8080/actuator/health
curl http://localhost:8080/actuator/info

Instructions

1. Add Actuator Dependency

Include spring-boot-starter-actuator in your build configuration.

Validate: Restart the service and confirm /actuator/health and /actuator/info respond with 200 OK.

2. Expose Required Endpoints

• Set management.endpoints.web.exposure.include to the precise list or "*" for internal deployments.
• Adjust management.endpoints.web.base-path (e.g., /management) when the default /actuator conflicts with routing.
• Review detailed endpoint semantics in references/endpoint-reference.md.

Validate: curl http://localhost:8080/actuator returns the list of exposed endpoints.

3. Secure Management Traffic

• Apply an isolated SecurityFilterChain using EndpointRequest.toAnyEndpoint() with role-based rules.
• Combine management.server.port with firewall controls or service mesh policies for operator-only access.
• Keep /actuator/health/** publicly accessible only when required; otherwise enforce authentication.

Validate: Unauthenticated requests to protected endpoints return 401 Unauthorized.

4. Configure Health Probes

• Enable management.endpoint.health.probes.enabled=true for /health/liveness and /health/readiness.
• Group indicators via management.endpoint.health.group.* to match platform expectations.
• Implement custom indicators by extending HealthIndicator or ReactiveHealthContributor; sample implementations in references/examples.md#custom-health-indicator.

Validate: /actuator/health/readiness returns UP with all mandatory components before promoting to production.

5. Publish Metrics and Traces

• Activate Micrometer exporters (Prometheus, OTLP, Wavefront, StatsD) via management.metrics.export.*.
• Apply MeterRegistryCustomizer beans to add application, environment, and business tags for observability correlation.
• Surface HTTP request metrics with server.observation.* configuration when using Spring Boot 3.2+.

Validate: Scrape /actuator/prometheus and confirm required meters (http.server.requests, jvm.memory.used) are present.

6. Enable Diagnostics Tooling

• Turn on /actuator/startup (Spring Boot 3.5+) and /actuator/conditions during incident response to inspect auto-configuration decisions.
• Register an HttpExchangeRepository (e.g., InMemoryHttpExchangeRepository) before enabling /actuator/httpexchanges for request auditing.
• Consult references/endpoint-reference.md for endpoint behaviors and limits.

Validate: /actuator/startup and /actuator/conditions return valid JSON payloads.

Examples

Basic – Expose health and info safely