https://docs.spring.io/spring-cloud-commons/reference/spring-cloud-commons/loadbalancer.html#_loadbalancer_integration_for_spring_http_service_clients_autoconfiguration
For each HTTP Service Client group, if the group baseUrl (defined under the spring.http.client.service.group.[groupName].base-url property) is null, a serviceId-based URL for load-balancing is set up as the baseUrl, with serviceId resolved from the HTTP Service Client groupName.
Is the configuration mentioned here supposed to be...?
spring.http.serviceclient.book.base-url=lb://book
???