Eureka never unregisters a service

Question

I'm currently facing an issue where Eureka does not unregister a registered service. I've pulled the Eureka server example straight from git hub and made only one change, eureka.enableSelfPreservation = false. My application.yml looks like this:

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

I've read that if 85% of the registered services stop delivering heartbeats within 15 minutes, Eureka assumes the issue is network related and does not de-register the services that are not responding. In my case I have only one service running, so I disabled self-preservation mode. I am abruptly killing the process and Eureka leaves the service registered for what seems like an indefinite amount of time.

My client's application.yml looks like this:

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}}

My goal is to create a demo where Eureka quickly detects the service is no longer running and another service that is started can quickly register itself.

As of now, once the eureka client is started, it registers in 3 seconds. It just never un-registers when the service is abruptly terminated. After I kill the service, the Eureka dashboard reads:

EMERGENCY! EUREKA MAY BE INCORRECTLY CLAIMING INSTANCES ARE UP WHEN THEY'RE NOT. RENEWALS ARE LESSER THAN THRESHOLD AND HENCE THE INSTANCES ARE NOT BEING EXPIRED JUST TO BE SAFE.

How can I prevent this behavior?

Solution 1

I realized that self preservation mode was never actually being disabled. It turns out the actual property is

eureka.server.enableSelfPreservation=false

(See DefaultEurekaServerConfig Code), which I haven't found documented anywhere. This resolved my issue.

Solution 2

I made service de-registration work by setting the below values

Eureka server application.yml

eureka:
  server:
    enableSelfPreservation: false

Service application.yml

eureka:
  instance:
    leaseRenewalIntervalInSeconds: 1
    leaseExpirationDurationInSeconds: 2

The full example is here https://github.com/ExampleDriven/spring-cloud-eureka-example

Comments

[DtechNet]

A pull request to the documentation repo for this issue would probably be very helpful for many others. ... If someone hasn't done so already.

[Mindwin]

Aren't these values too short?

[Peter Szanto]

the values are just examples, based on your use case you have to find the right values. The above setting will put much more load on the eureka server, but it will reduce the risk of forwarding traffic to a non working service

[Balasubramanian Rengasamy]

This resolves my issue