Eureka client sometimes registrates with wrong host name - cluster-computing

Question

I have a question about eureka like this question but the solution of this issue were of no help at all. See the similar issue here:
Another similar issue
Well, in my issue, I'm trying to construct a graceful release module based on eureka. By pull down any service in eureka before actually shut them down to ensure there is no loadbalance exception when the specified application is closed.
I have tested the situations to set eureka.instance.preferIpAddressto false and true.
while eureka.instance.preferIpAddress=false,ribbon will not recognize those applications registered with machine name and will throw a no loadbalancer exception.
while eureka.instance.preferIpAddress=false,ribbon will recognize those applications registered with machine name and everything is going right. That means, ribbon can get the real ip address of those applications.
Here is my case, I need to not only figure out why in both situations, the instanceId of applications in eureka will still showing with machine name, but also the same application will
get chance to have different instanceId even after simple restart!
Here is what I observed:
Server IP is 192.168.24.201 with hosts setting it's name to localhost
restart the same application in several times It can be seen that sometimes the instanceId of this application will change between localhost:applicationName:8005 and 192.168.24.201:applicationName:8005.
But both instanceId have the same IP address. And that means both of them won't lead to a loadbalance exception. It only makes my manually controlling of eureka server more difficult. And that is also acceptable.
The biggest problem is, sometimes the instanceId of different server will be localhost:applicationName:8005 and that leads to conflicts! By restart the application, the situation will solve in chance but not all the times! So if I'm using eureka as a cluster of several server, I cannot ensure my application is correctly registrate into eureka!
Here is the eureka client setting of application8005:
eureka:
instance:
lease-renewal-interval-in-seconds: ${my-config.eureka.instance.heartbeatInterval:5}
lease-expiration-duration-in-seconds: ${my-config.eureka.instance.deadInterval:15}
preferIpAddress: true
client:
service-url:
defaultZone: http://192.168.24.201:8008/eureka/
registry-fetch-interval-seconds: ${my-config.eureka.client.fetchRegistryInterval:20}
Here is the eureka server setting of EurekaServer:
eureka:
server:
eviction-interval-timer-in-ms: ${my-config.eureka.server.refreshInterval:5000}
enable-self-preservation: false
responseCacheUpdateIntervalMs: 5000
I don't know why applications' instanceId will sometimes not using IP as beginning string but using localhost.

Answer 1

The problem was solved by using prefer-ip-address: true and instance-id: ${spring.cloud.client.ip-address}:${spring.application.name}:${server.port}:${spring.cloud.nacos.config.group}
I have ruled that each server can run only one same app.
In this case each instance will have it's own unique id in this way.