In this case, the cluster name from 4 services is pulled from their metadata map, and is expected to have values that include "SYSTEM" and "USER".
To use the "default" cluster for all apps you need a string literal expression (with single quotes):
To use the "default" cluster for all apps you need a string literal expression (with single quotes, and escaped with double quotes if it is in YAML as well):
----
turbine:
appConfig: customers,stores
clusterNameExpression: 'default'
clusterNameExpression: "'default'"
----
Spring Cloud provides a `spring-cloud-starter-turbine` that has all the dependencies you need to get a Turbine server running. Just create a Spring Boot application and annotate it with `@EnableTurbine`.