---
title: "Prerequisites"
url: "https://axoflow.com/docs/axosyslog-core/4.28/chapter-destinations/configuring-destinations-kafka/destination-kafka-prerequisites/"
last_modified: "2023-06-27T21:05:00+02:00"
---

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

# Prerequisites

To publish messages from AxoSyslog to Apache Kafka, 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 latest stable binary release of the Apache Kafka libraries (version 0.9 or newer) from <http://kafka.apache.org/downloads.html>.
3. Extract the Apache Kafka libraries into a single directory. If needed, collect the various `.jar` files into a single directory (for example, `/opt/kafka/lib/`) where AxoSyslog can access them. You must specify this directory in the AxoSyslog configuration file.
4. Check if the following files in the Kafka libraries have the same version number: `slf4j-api-<version-number>.jar`, `slf4j-log4j12-<version-number>.jar`. If the version number of these files is different, complete the following steps:

   1. Delete one of the files (for example, `slf4j-log4j12-<version-number>.jar`).
   2. Download a version that matches the version number of the other file (for example, 1.7.6) from the [official SLF4J distribution](http://www.slf4j.org/download.html).
   3. Copy the downloaded file into the directory of your Kafka library files (for example, `/opt/kafka/lib/`).

Last modified June 27, 2023: [Moves content/docs to content/ to shorten output url (a5fcf1ed)](https://github.com/axoflow/axosyslog-core-docs/commit/a5fcf1ed4956f586bc12af2b775e10aa75c1e630)