public void startAutoMatchingServiceHierarchy() {
        if (!this.isEnableHierarchy) {
            return;
        }
        Executors.newSingleThreadScheduledExecutor()
                 .scheduleWithFixedDelay(
                     new RunnableWithExceptionProtection(this::autoMatchingServiceRelation, t -> log.error(
                         "Scheduled auto matching service hierarchy from service traffic failure.", t)), 30, 20, TimeUnit.SECONDS);
    }
Build the hierarchy relation between the 2 instances. the `serviceLayer` and `relatedServiceLayer` hierarchy
relations should be defined in `config/hierarchy-definition.yml`.

@param upperInstanceName        the name of the upper instance
@param upperServiceName         the name of the upper service
@param upperServiceLayer        the layer of the upper service
@param lowerInstanceName the name of the lower related instance
@param lowerServiceName  the name of the lower related service
@param lowerServiceLayer the layer of the lower related service
oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/hierarchy/HierarchyService.java