在liveness中配置/actuator/health，在应用请求nacos失败时，会导致pod异常重启

[ZhXZhao]

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Which Component

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
            <version>2.3.12.RELEASE</version>
        </dependency>

Describe the bug k8s应用在liveness中配置/actuator/health，应用请求nacos失败时，会导致pod异常重启，应用自身状态无异常，可以接受外部请求。

To Reproduce Steps to reproduce the behavior:

1. 启动一个简单的SpringCloudAlibaba应用，并引入nacos config、discovery以及actuator依赖

       <dependency>
           <groupId>com.alibaba.cloud</groupId>
           <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
       </dependency>
       <dependency>
           <groupId>com.alibaba.cloud</groupId>
           <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
       </dependency>
       <dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-starter-actuator</artifactId>
       </dependency>

2. 访问http://localhost:8088/actuator/health

{
    "status": "UP",
    "components": {
        "discoveryComposite": {
            "status": "UP",
            "components": {
                "discoveryClient": {
                    "status": "UP",
                    "details": {
                        "services": [
                            "provider"
                        ]
                    }
                }
            }
        },
        "diskSpace": {
            "status": "UP",
            "details": {
                "total": 499963174912,
                "free": 285202673664,
                "threshold": 10485760,
                "exists": true
            }
        },
        "nacosConfig": {
            "status": "UP"
        },
        "nacosDiscovery": {
            "status": "UP"
        },
        "ping": {
            "status": "UP"
        },
        "refreshScope": {
            "status": "UP"
        }
    }
}

3. 通过添加网络白名单策略，模拟应用与nacos之间断连的情况，再次访问http://localhost:8088/actuator/health

{
    "status": "DOWN",
    "components": {
        "discoveryComposite": {
            "status": "UP",
            "components": {
                "discoveryClient": {
                    "status": "UP",
                    "details": {
                        "services": []
                    }
                }
            }
        },
        "diskSpace": {
            "status": "UP",
            "details": {
                "total": 499963174912,
                "free": 284207394816,
                "threshold": 10485760,
                "exists": true
            }
        },
        "nacosConfig": {
            "status": "UP"
        },
        "nacosDiscovery": {
            "status": "DOWN"
        },
        "ping": {
            "status": "UP"
        },
        "refreshScope": {
            "status": "UP"
        }
    }
}

4. 此时actuator判断应用的健康状态为"DOWN"，但实际上应用实际仍可以对外提供服务

Expected behavior 在SCA应用与nacos之间连接失败时，/actuator/health状态不应该为"DOWN"

Additional context SCA Version 2.2.9.RELEASE

[chickenlj]

In general, the "Liveness" state should not be based on external checks, such as Health checks. If it did, a failing external system (a database, a Web API, an external cache) would trigger massive restarts and cascading failures across the platform.

[chickenlj]

I think there's no need to change the implementations of NacosConfigHealthIndicator and NacosDiscoveryHealthIndicator, they both work well for telling actuator/health the status of Nacos.

Spring Boot has already provided Liveness and Readiness probes since 2.3.x, users should always use /actuator/health/liveness and /actuator/health/readiness for container lifecycle testing instead of using /actuator/health:

• https://docs.spring.io/spring-boot/docs/3.2.1/reference/htmlsingle/#features.spring-application.application-availability
• https://docs.spring.io/spring-boot/docs/3.2.1/reference/htmlsingle/#actuator.endpoints.kubernetes-probes

[yuluo-yx]

I think there's no need to change the implementations of NacosConfigHealthIndicator and NacosDiscoveryHealthIndicator, they both work well for telling actuator/health the status of Nacos.

Spring Boot has already provided Liveness and Readiness probes since 2.3.x, users should always use /actuator/health/liveness and /actuator/health/readiness for container lifecycle testing instead of using /actuator/health:

• https://docs.spring.io/spring-boot/docs/3.2.1/reference/htmlsingle/#features.spring-application.application-availability
• https://docs.spring.io/spring-boot/docs/3.2.1/reference/htmlsingle/#actuator.endpoints.kubernetes-probes

Agree.

[chickenlj]

We need one article on sca.aliyun.com giving best practices for deploying Spring Cloud Alibaba on Kubernetes.

[ZhXZhao]

I think there's no need to change the implementations of NacosConfigHealthIndicator and NacosDiscoveryHealthIndicator, they both work well for telling actuator/health the status of Nacos.

Spring Boot has already provided Liveness and Readiness probes since 2.3.x, users should always use /actuator/health/liveness and /actuator/health/readiness for container lifecycle testing instead of using /actuator/health:

• https://docs.spring.io/spring-boot/docs/3.2.1/reference/htmlsingle/#features.spring-application.application-availability
• https://docs.spring.io/spring-boot/docs/3.2.1/reference/htmlsingle/#actuator.endpoints.kubernetes-probes

Thanks. Could you give some suggestions for users using spring boot version lower than 2.3.x?

[github-actions[bot]]

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[yuluo-yx]

hi, @ZhXZhao I have written a best practice here. Do you have time to review?

https://github.com/yuluo-yx/sca-k8s-demo/tree/openfeign

[ZhXZhao]

hi, @ZhXZhao I have written a best practice here. Do you have time to review?

https://github.com/yuluo-yx/sca-k8s-demo/tree/openfeign

Okay, that's great