Stream<ConfigChangeAction> findConfigChangesFromModels(AbstractConfigProducerRoot currentModel,
                                                           AbstractConfigProducerRoot nextModel,
                                                           DeployLogger logger) {
        return nextModel.getDescendantServices().stream()
                .map(service -> findConfigChangeActionForService(service, currentModel, nextModel, logger))
                .filter(Optional::isPresent)
                .map(Optional::get);
    }
Inspects the configuration in the new and old Vespa model to determine which services that require restart
config-model/src/main/java/com/yahoo/vespa/model/application/validation/change/ConfigValueChangeValidator.java