Eureka replicas unavailable

Question

I have problem with configuring eureka replicas :

Eureka service :

@EnableEurekaServer
@SpringBootApplication
public class DiscoveryService {

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

bootstrap.properties

spring.application.name=discovery
spring.cloud.config.uri=http://localhost:8888

I also have two yml files

for server 1 runing on 8761

eureka.client.serviceUrl.defaultZone:http://localhost:8762/eureka/
eureka.client.registerWithEureka:false
eureka.client.fetchRegistry:false

for server 2 running on 8762

eureka.client.serviceUrl.defaultZone:http://localhost:8761/eureka/
eureka.client.registerWithEureka:false
eureka.client.fetchRegistry:false

I can enter both dashboards, but I see that both instance have this:

registered-replicas http://localhost:8761/eureka/
unavailable-replicas    http://localhost:8761/eureka/,
available-replicas

Why is that ?

Solution

I'm guessing your eurekas don't register themselves with localhost as their hostnames so this is why you're seeing them as unavailable in the eureka dashboards. Eureka uses this pattern a lot, it matches the service url with the caller hostname to determine replication context.

Peer eureka nodes are fetched in com.netflix.eureka.cluster.PeerEurekaNodes::resolvePeerUrls from the list of eureka service urls (eureka.client.serviceUrl key or DNS based). Later on, this list is matched against currently registered eureka applications in com.netflix.eureka.util.StatusUtil::getStatusInfo by using the hostname to get the replica statuses.

Since your application most likely doesn't register itself with localhost, it'll get added to the unavailable replicas.

Comments

[Doug]

So you are saying we need to set eureka.instance.hostname=localhost ?

[Doug]

I changed eureka.instance.hostname=peer0 to eureka.instance.hostname=machine_ip. I also had eureka.client.register-with-eureka set to false, so I had to change that to true. Now it works. thanks

[jebeaudet]

The hostname used in eureka.client.serviceUrl should match the one in eureka.instance.hostname for the eureka server.

[Jef]

thanks, bro. I was struggling with this for a long time. Replaced my Host IP based configuration to hostname based and now it works like a charm.