Eureka on spring-cloud-netflix with DNS based config, all instances showing up as unavailable

Question

I'm trying to setup a eureka cluster on aws with DNS-based EIP configuration as described at https://github.com/Netflix/eureka/wiki/Configuring-Eureka-in-AWS-Cloud

Everything seems to work, but the eureka dashboard insists that the eureka instances are unavailable. I'm now wondering if this is only an ui problem (i think so) or if i'm missing something.

As i understand the "unavailable-replicas" logic in the dashboard this is because eureka is comparing the registration hostname and the replica hostname. The instances register with their internal VPC ip at the discovery client but with their EIP when looking for replica peers (strange enough, in the eureka log i can see internaly they are also using the internal VPC ip).

The question is: Is that only some cosmetic ui problem that i shouldn't worry about or are bigger problems waiting to step in because of some misconfiguration? If it's only an ui thing: can i "repair" that somehow?

Edit:

Maybe related https://github.com/spring-cloud/spring-cloud-netflix/issues/102#issuecomment-74446709

Answer 1

With the help of @rozhok in the related github issue i now have a working solution. If anyone is facing the same problem, here's what i've done:

application.yml

eureka:
  datacenter: cloud
  client:
    eurekaServerDNSName: your.dns.name
    eurekaServerPort: 8761
    eurekaServerURLContext: eureka
    region: eu-west-1
    registerWithEureka: true
    fetchRegistry: true
    useDnsForFetchingServiceUrls: true
  server:
    waitTimeInMsWhenSyncEmpty: 0
    enableSelfPreservation: true

EurekaServer

@SpringBootApplication
@EnableEurekaServer
@EnableDiscoveryClient
public class EurekaServer {

    @Value("${server.port:8761}") 
    private int port;

    public static void main(String[] args) {
        SpringApplication.run(EurekaServer.class, args);
    }

    @Bean
    @Autowired
    public EurekaInstanceConfigBean eurekaInstanceConfigBean(InetUtils inetUtils) {
      EurekaInstanceConfigBean config = new EurekaInstanceConfigBean(inetUtils);
      AmazonInfo info = AmazonInfo.Builder.newBuilder().autoBuild("eureka");

      // Don't use spring cloud's hostname here. 
      // See comment below by Michal
      config.setHostname(
          info.get(AmazonInfo.MetaDataKey.publicHostname));

      config.setIpAddress(info.get(AmazonInfo.MetaDataKey.publicIpv4));
      config.setNonSecurePort(port);
      config.setDataCenterInfo(info);
      return config;
    }

}

With that configuration each eureka server sees only the other servers as available replicas: