Failed to resolve service with Spring Cloud LoadBalancer - spring

Question

I followed this guide to implement a simple client-side load balancer in a Spring Boot application. Below is the code:
#RestController
class MyController(
val loadBalancedWebClientBuilder: WebClient.Builder
) {
private fun makeRequest() {
loadBalancedWebClientBuilder.build().post()
.uri(URI("http://my-service/endpoint"))
.body(BodyInserters.fromValue("{ \"data\" = \"data\" }"))
.retrieve()
.bodyToMono(String::class.java)
.block()
}
}
Here is the WebClient configuration:
#Configuration
#LoadBalancerClient(name = "my-service", configuration = [LoadBalancerConfig::class])
class WebClientConfig {
#LoadBalanced
#Bean
fun webClientBuilder(): WebClient.Builder {
return WebClient.builder()
}
}
And the load balancer configuration:
class LoadBalancerConfig {
#Bean
#Primary
fun serviceInstanceListSupplier(): ServiceInstanceListSupplier {
return ServiceInstanceListSupplerImpl("my-service")
}
}
class ServiceInstanceListSupplerImpl(private val serviceId: String) : ServiceInstanceListSupplier {
override fun getServiceId(): String {
return serviceId
}
override fun get(): Flux<List<ServiceInstance>> {
return Flux.just(listOf("http://localhost").mapIndexed { index, s ->
DefaultServiceInstance(index.toString(), serviceId, s, 8088, true) })
}
}
Finally, in the configuration file I have the below:
spring:
cloud:
discovery:
client:
simple:
instances:
my-service[0].uri: http://localhost:8088
When running the above, the following exception gets thrown:
org.springframework.web.reactive.function.client.WebClientRequestException: Failed to resolve 'my-service' after 4 queries ; nested exception is java.net.UnknownHostException: Failed to resolve 'my-service' after 4 queries
at org.springframework.web.reactive.function.client.ExchangeFunctions$DefaultExchangeFunction.lambda$wrapException$9(ExchangeFunctions.java:141) ~[spring-webflux-5.3.24.jar:5.3.24]
Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException:
Error has been observed at the following site(s):
*__checkpoint ⇢ Request to POST http://my-service/endpoint [DefaultWebClient]
Original Stack Trace:
at org.springframework.web.reactive.function.client.ExchangeFunctions$DefaultExchangeFunction.lambda$wrapException$9(ExchangeFunctions.java:141) ~[spring-webflux-5.3.24.jar:5.3.24]
at reactor.core.publisher.MonoErrorSupplied.subscribe(MonoErrorSupplied.java:55) ~[reactor-core-3.4.25.jar:3.4.25]
at reactor.core.publisher.Mono.subscribe(Mono.java:4490) ~[reactor-core-3.4.25.jar:3.4.25]
at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onError(FluxOnErrorResume.java:103) ~[reactor-core-3.4.25.jar:3.4.25]
at reactor.core.publisher.FluxPeek$PeekSubscriber.onError(FluxPeek.java:222) ~[reactor-core-3.4.25.jar:3.4.25]
at reactor.core.publisher.FluxPeek$PeekSubscriber.onError(FluxPeek.java:222) ~[reactor-core-3.4.25.jar:3.4.25]
at reactor.core.publisher.FluxPeek$PeekSubscriber.onError(FluxPeek.java:222) ~[reactor-core-3.4.25.jar:3.4.25]
at reactor.core.publisher.MonoNext$NextSubscriber.onError(MonoNext.java:93) ~[reactor-core-3.4.25.jar:3.4.25]
at reactor.core.publisher.MonoFlatMapMany$FlatMapManyMain.onError(MonoFlatMapMany.java:204) ~[reactor-core-3.4.25.jar:3.4.25]
at reactor.core.publisher.SerializedSubscriber.onError(SerializedSubscriber.java:124) ~[reactor-core-3.4.25.jar:3.4.25]
...
Any clue what might be wrong?