Eureka 从不注销服务

Question

我目前面临一个问题，即 Eureka 无法取消注册已注册的服务。我直接从 git hub 中提取了 Eureka 服务器示例，并且只进行了一项更改，eureka.enableSelfPreservation = false。我的 application.yml 看起来像这样：

server:
  port: 8761
eureka:
  enableSelfPreservation: false
  client:
    registerWithEureka: false
fetchRegistry: false
  server:
    waitTimeInMsWhenSyncEmpty: 0

我了解到，如果 85% 的已注册服务在 15 分钟内停止发送心跳，Eureka 会假定问题与网络相关，并且不会取消注册未响应的服务。就我而言，我只运行了一项服务，所以我禁用了自我保护模式。我突然终止了该进程，并且 Eureka 让服务注册了似乎无限期的时间。

我客户的 application.yml 如下所示：

eureka:
  instance:
    leaseRenewalIntervalInSeconds: 3
  client:
    healthcheck:
      enabled: true
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/
  appInfo:
    replicate:
      interval: 3
    initial:
      replicate:
        time: 3
spring:
  rabbitmq:
    addresses: ${vcap.services.${PREFIX:}rabbitmq.credentials.uri:amqp://${RABBITMQ_HOST:localhost}:${RABBITMQ_PORT:5672}}

我的目标是创建一个演示，让 Eureka 快速检测到服务不再运行，而另一个启动的服务可以快速注册自己。

截至目前，eureka客户端一旦启动，3秒就注册完成。当服务突然终止时，它永远不会取消注册。在我终止服务后，Eureka 仪表板显示：

紧急情况！ EUREKA 可能不正确地声称实例已启动，但实际上并未启动。续订少于阈值，因此为了安全起见，实例不会过期。

如何防止这种行为？

Answer 1

我意识到自我保护模式从未真正被禁用。原来实际的属性是

eureka.server.enableSelfPreservation=false

（参见DefaultEurekaServerConfig 代码），我在任何地方都没有找到相关文档。这解决了我的问题。

Answer 2

我通过设置以下值使服务注销工作

尤里卡服务器应用程序.yml

eureka:
  server:
    enableSelfPreservation: false

服务应用程序.yml

eureka:
  instance:
    leaseRenewalIntervalInSeconds: 1
    leaseExpirationDurationInSeconds: 2

完整的例子在这里https://github.com/ExampleDriven/spring-cloud-eureka-example

Answer 3

经过一番苦苦挣扎，如果由于某些问题从 Eureka 服务器取消注册任何服务，我终于得到了解决方案。它将通过扩展 Eureka-Server API 的 HealthCallback 来通知管理员。 Let Say Service-A 向 Eureka 注册。因此，Eureka Client 与 Service-A 集成，并在 Service A 中实现以下回调。

Service-A [Eureka-Client] 在属性文件中添加以下属性。

#Eureka Configuration
eureka.client.eureka-server-port=8761
eureka.client.register-with-eureka=true
eureka.client.healthcheck.enabled=false
eureka.client.prefer-same-zone-eureka=true
eureka.client.fetchRegistry=true
eureka.client.serviceUrl.defaultZone=${eurekaServerURL1}, ${eurekaServerURL2}
eureka.client.eureka.service-url.defaultZone=${eurekaServerURL1}, ${eurekaServerURL2}
eureka.instance.hostname=${hostname}
eureka.client.lease.duration=30
eureka.instance.lease-renewal-interval-in-seconds=30
eureka.instance.lease-expiration-duration-in-seconds=30

添加以下java文件。

@Component
public class EurekaHealthCheckHandler implements HealthCheckHandler, ApplicationContextAware, InitializingBean {


    static Logger logger = LoggerFactory.getLogger(EurekaHealthCheckHandler.class);

    private static final Map<Status, InstanceInfo.InstanceStatus> healthStatuses = new HashMap<Status, InstanceInfo.InstanceStatus>() {{
        put(Status.UNKNOWN, InstanceInfo.InstanceStatus.UNKNOWN);
        put(Status.OUT_OF_SERVICE, InstanceInfo.InstanceStatus.OUT_OF_SERVICE);
        put(Status.DOWN, InstanceInfo.InstanceStatus.DOWN);
        put(Status.UP, InstanceInfo.InstanceStatus.UP);
    }};

@Autowired
ComunocationService comunocationService ;
    private final CompositeHealthIndicator healthIndicator;

    private ApplicationContext applicationContext;

    public EurekaHealthCheckHandler(HealthAggregator healthAggregator) {
        Assert.notNull(healthAggregator, "HealthAggregator must not be null");
        this.healthIndicator = new CompositeHealthIndicator(healthAggregator);

        Health health = healthIndicator.health();
        logger.info(" =========== Testing =========== {}", health.toString() );
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext = applicationContext;
    }

    @Override
    public void afterPropertiesSet() throws Exception {

        final Map<String, HealthIndicator> healthIndicators = applicationContext.getBeansOfType(HealthIndicator.class);
        for (Map.Entry<String, HealthIndicator> entry : healthIndicators.entrySet()) {
            logger.info("======"+ entry.getKey() +"============= "+entry.getValue());
            healthIndicator.addHealthIndicator(entry.getKey(), entry.getValue());
        }
    }

    @Override
    public InstanceInfo.InstanceStatus getStatus(InstanceInfo.InstanceStatus instanceStatus) {
        logger.info("============== Custome Eureka Implementation ==================="+ getHealthStatus());
        return getHealthStatus();
    }

    protected InstanceInfo.InstanceStatus getHealthStatus() {
        final Status status = healthIndicator.health().getStatus();
        return mapToInstanceStatus(status);
    }

    protected InstanceInfo.InstanceStatus mapToInstanceStatus(Status status) {
        logger.info("============== Test Custome Eureka Implementation ==================={}", status);
        if(status.equals(InstanceInfo.InstanceStatus.UP)) {
            // Send mail after configured times
              comunocationService.sendEmail("ServiceName");
        }
        if(!healthStatuses.containsKey(status)) {
            return InstanceInfo.InstanceStatus.UNKNOWN;
        }
        return healthStatuses.get(status);
    }

    public void getstatusChangeListner() {
        ApplicationInfoManager.StatusChangeListener statusChangeListener = new ApplicationInfoManager.StatusChangeListener() {
            @Override
            public String getId() {
                return "statusChangeListener";
            }
            @Override
            public void notify(StatusChangeEvent statusChangeEvent) {
                if (InstanceStatus.DOWN == statusChangeEvent.getStatus() ||
                        InstanceStatus.DOWN == statusChangeEvent.getPreviousStatus()) {
                    // log at warn level if DOWN was involved
                    logger.warn("Saw local status change event {}", statusChangeEvent);
                } else {
                    logger.info("Saw local status change event {}", statusChangeEvent);
                }

            }
        };
    }


}

和

@Configuration
public class EurekaHealthCheckHandlerConfiguration {

    @Autowired(required = false)
    private HealthAggregator healthAggregator = new OrderedHealthAggregator();

    @Bean
    @ConditionalOnMissingBean
    public EurekaHealthCheckHandler eurekaHealthCheckHandler() {
        return new EurekaHealthCheckHandler(healthAggregator);
    }
}

这是绝对有效且经过良好测试的代码