---
title: "Prerequisites"
url: "https://axoflow.com/docs/axosyslog-core/4.28/chapter-destinations/configuring-destinations-hdfs/destination-hdfs-prerequisites/"
last_modified: "2024-08-28T14:21:40+02:00"
---

> For the complete documentation index, see [llms.txt](https://axoflow.com/docs/axosyslog-core/4.28/llms.txt).

# Prerequisites

To send messages from AxoSyslog to HDFS, complete the following steps.

## Steps:

1. If you want to use the Java-based modules of AxoSyslog (for example, the Elasticsearch, HDFS, or Kafka destinations), you must compile AxoSyslog with Java support.

   - Download and install the Java Runtime Environment (JRE), 1.7 (or newer). You can use OpenJDK or Oracle JDK, other implementations are not tested.
   - Install [gradle](https://gradle.org/install) version 2.2.1 or newer.
   - Set `LD_LIBRARY_PATH` to include the `libjvm.so` file, for example:`LD_LIBRARY_PATH=/usr/lib/jvm/java-7-openjdk-amd64/jre/lib/amd64/server:$LD_LIBRARY_PATH`

     Note that many platforms have a simplified links for Java libraries. Use the simplified path if available. If you use a startup script to start AxoSyslog set `LD_LIBRARY_PATH` in the script as well.
   - If you are behind an HTTP proxy, create a `gradle.properties` under the `modules/java-modules/` directory. Set the proxy parameters in the file. For details, see [The Gradle User Guide](https://docs.gradle.org/current/userguide/build_environment.html#sec:gradle_properties_and_system_properties).
2. Download the Hadoop Distributed File System (HDFS) libraries (version 2.x) from <http://hadoop.apache.org/releases.html>.
3. Extract the HDFS libraries into a temporary directory, then collect the various `.jar` files into a single directory (for example, `/opt/hadoop/lib/`) where AxoSyslog can access them. You must specify this directory in the AxoSyslog configuration file. The files are located in the various `lib` directories under the `share/` directory of the Hadoop release package. (For example, in Hadoop 2.7, required files are `common/hadoop-common-2.7.0.jar`, `common/libs/*.jar`, `hdfs/hadoop-hdfs-2.7.0.jar`, `hdfs/lib/*`, but this may change between Hadoop releases, so it is easier to copy every `.jar` file into a single directory.

Last modified August 28, 2024: [Formatting fixes (c26e237b)](https://github.com/axoflow/axosyslog-core-docs/commit/c26e237bf3d7aa0eece69730979d4af442ff8130)