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docs: update health check

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Ilkka Seppälä
2024-05-26 11:04:54 +03:00
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commit fe9e7f9d7d
1 changed files with 6 additions and 22 deletions
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health-check/README.md
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@@ -20,13 +20,11 @@ The Health Check pattern is designed to proactively monitor the health of indivi
## Explanation
In microservices architecture, it's critical to continuously check the health of individual services. The Health Check Pattern is a mechanism for microservices to expose their health status. This pattern is implemented by including a health check endpoint in microservices that returns the service's current state. This is vital for maintaining system resilience and operational readiness.
Real-world example
> In a cloud-native environment, such as Kubernetes or AWS ECS, health checks are used to ensure that containers are running correctly. If a service fails its health check, it can be automatically restarted or replaced, ensuring high availability and resilience.
> Consider a hospital where patient monitoring systems are used to ensure the health of patients. Each monitoring device periodically checks the vital signs of a patient (such as heart rate, blood pressure, and oxygen levels) and reports back to a central system. If any device detects abnormal vital signs, it triggers an alert for immediate medical attention. Similarly, in software, a Health Check pattern allows each service to periodically report its status to a central monitoring system. If a service is found to be unhealthy, the system can take corrective actions such as alerting administrators, restarting the service, or redirecting traffic to healthy instances, thereby ensuring continuous and reliable operation.
In Plain Words
In plain words
> The Health Check Pattern is like a regular doctor's visit for services in a microservices architecture. It helps in early detection of issues and ensures that services are healthy and available.
@@ -39,13 +37,6 @@ In the provided code, we can see an example of the Health Check pattern in the `
The `App` class is the entry point of the application. It starts a Spring Boot application which has health check capabilities built-in through the use of Spring Boot Actuator.
```java
package com.iluwatar.health.check;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.scheduling.annotation.EnableScheduling;
@EnableCaching
@EnableScheduling
@SpringBootApplication
@@ -61,10 +52,6 @@ Spring Boot Actuator provides several built-in health checks through its `/actua
To add a custom health check, you can create a class that implements the `HealthIndicator` interface and override its `health` method. Here is an example:
```java
import org.springframework.boot.actuate.health.Health;
import org.springframework.boot.actuate.health.HealthIndicator;
import org.springframework.stereotype.Component;
@Component
public class CustomHealthCheck implements HealthIndicator {
@Override
@@ -88,13 +75,10 @@ In this example, the `check` method contains the logic for the health check. If
This is a basic example of the Health Check pattern, where health checks are built into the system and can be easily accessed and monitored.
## Class Diagram
![Health Check Pattern](./etc/health-check.png)
## Applicability
This pattern is applicable in microservices architectures, distributed systems, or any complex system where it’s crucial to continuously check the health of various software components to ensure system reliability and availability.
* Use when building microservices or distributed systems where it is crucial to monitor the health of each service.
* Suitable for scenarios where automated systems need to determine the operational status of services to perform load balancing, failover, or recovery operations.
## Known Uses
@@ -122,6 +106,6 @@ Trade-offs:
## Credits
* [Health Check API pattern on Microservices.io](https://microservices.io/patterns/observability/health-check-api.html)
* [Release It! Design and Deploy Production-Ready Software](https://amzn.to/3Uul4kF)
* [Microservices Patterns: With examples in Java](https://amzn.to/3UyWD5O)
* [Release It! Design and Deploy Production-Ready Software](https://amzn.to/3Uul4kF)
* [Pattern: Health Check API (Microservices.io)](https://microservices.io/patterns/observability/health-check-api.html)