private void writeMetaFile(byte[] input, String status) {
        Path metaPath = getZKPath(getMetaPath());
        StringWriter writer = new StringWriter();
        try {
            mapper.writeValue(writer, new MetaData(status, input == null ? "" : ConfigUtils.getMd5(input)));
            log.log(Level.FINE, () -> "Writing meta file to " + metaPath);
            zkApp.putData(metaPath, writer.toString());
        } catch (IOException e) {
            throw new RuntimeException("Error writing meta file to " + metaPath, e);
        }
    }
@author Ulf Lilleengen
@author Vegard Havdal
configserver/src/main/java/com/yahoo/vespa/config/server/zookeeper/ZKApplicationFile.java