How to find the health of dependent micro service - Java

 This  is  from  AI Overview

To determine the health of a dependent microservice in a Java application, particularly within a Spring Boot environment, the following approaches can be utilized:

1. Spring Boot Actuator Health Endpoints:

Integrate Spring Boot Actuator: Add the spring-boot-starter-actuator dependency to the dependent microservice's pom.xml (Maven) or build.gradle (Gradle).

Code

    <dependency>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-starter-actuator</artifactId>

    </dependency>

Default Health Checks:

With Actuator, a /actuator/health endpoint becomes available, providing a high-level "UP" or "DOWN" status. It automatically includes checks for common components like disk space, database connectivity (if configured), and more.

Custom Health Indicators:

Implement the HealthIndicator interface to define custom health checks for specific dependencies or business logic within the dependent microservice. This allows for detailed status reporting on critical components.

2. MicroProfile Health (for Jakarta EE/MicroProfile-based applications):

Implement MicroProfile Health:

Utilize the MicroProfile Health API to define liveness, readiness, and startup checks within the dependent microservice.

Expose Health Endpoints:

This provides standardized endpoints (e.g., /health/live, /health/ready, /health/started) that can be used by orchestrators like Kubernetes for managing service lifecycle.

3. Direct API Calls (for non-standardized health checks):

Expose Custom Endpoints:

If the dependent microservice does not use Actuator or MicroProfile Health, it can expose custom HTTP endpoints that perform internal checks and return a status.

Invoke from Dependent Service:

The main microservice can then periodically invoke these custom endpoints to ascertain the health of its dependencies.

4. External Monitoring Tools and Watchdogs:

Monitoring Platforms:

Integrate with external monitoring tools (e.g., Prometheus, Grafana, ELK Stack) that can collect health metrics and alerts from microservices.

Watchdog Services:

Implement a dedicated "watchdog" service that periodically queries the health endpoints of all dependent microservices and can trigger alerts or even remediation actions based on detected issues.

5. Kubernetes Probes:

Liveness Probes:

Configure Kubernetes liveness probes to regularly check if the dependent microservice is still running and able to respond. If a probe fails, Kubernetes can restart the pod.

Readiness Probes:

Utilize readiness probes to ensure the dependent microservice is fully initialized and ready to receive traffic before directing requests to it. This prevents traffic from being routed to an unready instance during deployment or startup.

References from :-   AI  Review  ,    Health Monitoring in Microservice explained with Spring Boot