private void verifyClusterControllersOnlyDefinedForContent(ConfigModelRepo configModelRepo) {
        Admin admin = getAdmin();
        if (admin == null || admin.getClusterControllers() == null) return;
        if (configModelRepo.getContent() == null) {
            throw new IllegalArgumentException("Declaring <clustercontrollers> in <admin> in services.xml will not work when <content> is not defined");
        }
    }
Constructs a new config model given a context.

@param modelContext the model context.
config-model/src/main/java/com/yahoo/config/model/admin/AdminModel.java