eureka 各端缓存

Eureka Server端

public void contextInitialized(ServletContext context) {
   try {
      initEurekaEnvironment();
      // 1
      initEurekaServerContext();

      context.setAttribute(EurekaServerContext.class.getName(), this.serverContext);
   }
   catch (Throwable e) {
      log.error("Cannot bootstrap eureka server :", e);
      throw new RuntimeException("Cannot bootstrap eureka server :", e);
   }
}

1处，如下：

protected void initEurekaServerContext() throws Exception {
   // For backward compatibility
   JsonXStream.getInstance().registerConverter(new V1AwareInstanceInfoConverter(),
         XStream.PRIORITY_VERY_HIGH);
   XmlXStream.getInstance().registerConverter(new V1AwareInstanceInfoConverter(),
         XStream.PRIORITY_VERY_HIGH);

   if (isAws(this.applicationInfoManager.getInfo())) {
      this.awsBinder = new AwsBinderDelegate(this.eurekaServerConfig,
            this.eurekaClientConfig, this.registry, this.applicationInfoManager);
      this.awsBinder.start();
   }

   EurekaServerContextHolder.initialize(this.serverContext);

   log.info("Initialized server context");

   // Copy registry from neighboring eureka node
   int registryCount = this.registry.syncUp();
   // 2
   this.registry.openForTraffic(this.applicationInfoManager, registryCount);

   // Register all monitoring statistics.
   EurekaMonitors.registerAllStats();
}

com.netflix.eureka.registry.PeerAwareInstanceRegistryImpl#openForTraffic
@Override
public void openForTraffic(ApplicationInfoManager applicationInfoManager, int count) {
   super.openForTraffic(applicationInfoManager,
         count == 0 ? this.defaultOpenForTrafficCount : count);
}

com.netflix.eureka.registry.PeerAwareInstanceRegistryImpl#openForTraffic
@Override
public void openForTraffic(ApplicationInfoManager applicationInfoManager, int count) {
    // Renewals happen every 30 seconds and for a minute it should be a factor of 2.
    this.expectedNumberOfClientsSendingRenews = count;
    updateRenewsPerMinThreshold();
    logger.info("Got {} instances from neighboring DS node", count);
    logger.info("Renew threshold is: {}", numberOfRenewsPerMinThreshold);
    this.startupTime = System.currentTimeMillis();
    if (count > 0) {
        this.peerInstancesTransferEmptyOnStartup = false;
    }
    DataCenterInfo.Name selfName = applicationInfoManager.getInfo().getDataCenterInfo().getName();
    boolean isAws = Name.Amazon == selfName;
    if (isAws && serverConfig.shouldPrimeAwsReplicaConnections()) {
        logger.info("Priming AWS connections for all replicas..");
        primeAwsReplicas(applicationInfoManager);
    }
    logger.info("Changing status to UP");
    applicationInfoManager.setInstanceStatus(InstanceStatus.UP);
    super.postInit();
}

最终如下，加一个schedule任务：

com.netflix.eureka.registry.AbstractInstanceRegistry#postInit
protected void postInit() {
        renewsLastMin.start();
        if (evictionTaskRef.get() != null) {
            evictionTaskRef.get().cancel();
        }
        evictionTaskRef.set(new EvictionTask());
        evictionTimer.schedule(evictionTaskRef.get(),
                serverConfig.getEvictionIntervalTimerInMs(),
                // 1
                serverConfig.getEvictionIntervalTimerInMs());
    }

1处，这个时间，来自于：

com.netflix.eureka.DefaultEurekaServerConfig#getEvictionIntervalTimerInMs
@Override
public long getEvictionIntervalTimerInMs() {
    return configInstance.getLongProperty(
            namespace + "evictionIntervalTimerInMs", (60 * 1000)).get();
}

这个值，默认60s。