private static void writeConfig(String dir, String configName, ConfigInstance config) throws IOException {
        IOUtils.writeFile(dir + configName, StringUtilities.implodeMultiline(ConfigInstance.serialize(config)), false);
    }
Validates rank setup for all content clusters (rank-profiles, index-schema, attributes configs), validation is done
by running the binary 'vespa-verify-ranksetup-bin'

@author vegardh
config-model/src/main/java/com/yahoo/vespa/model/application/validation/RankSetupValidator.java