syslog-ng

syslog-ng is an enhanced log daemon, supporting a wide range of input
and output methods: syslog, unstructured text, message queues,
databases (SQL and NoSQL alike), and more.

Quickstart

The simplest configuration accepts system logs from /dev/log (from
applications or forwarded by systemd) and writes everything to a single
file:

@version: 4.8
@include "scl.conf"

log {
	source { system(); };
	destination { file("/var/log/syslog"); };
};

This one additionally processes logs from the network (TCP/514 by default):

@version: 4.8
@include "scl.conf"

log {
	source {
		system();
		network();
	};
	destination { file("/var/log/syslog"); };
};

This config is designed for structured/application logging, using local submission via JSON, and outputting in key=value format:

@version: 4.8
@include "scl.conf"

log {
	source { system(); };
	destination { file("/var/log/app.log" template("$(format-welf --subkeys .cim.)\n")); };
};

To submit a structured log using logger, you might run:

$ logger '@cim: {"name1":"value1", "name2":"value2"}'

In which case the resulting message will be:

name1=value1 name2=value2

For a brief introduction to configuring the syslog-ng application, see the quickstart guide.

Features

• Receive and send RFC3164
  and RFC5424 style syslog
  messages
• Receive and send JSON formatted messages
• Work with any kind of unstructured data
• Classify and structure logs using built-in parsers (csv-parser(),
  db-parser(), kv-parser(), etc.)
• Normalize, crunch, and process logs as they flow through the system
• Hand over logs for further processing using files, message queues (like
  AMQP), or databases (like
  PostgreSQL or
  MongoDB)
• Forward logs to big data tools (like Elasticsearch,
  Apache Kafka, or
  Apache Hadoop)

Performance

• syslog-ng provides performance levels comparable to a large
  cluster when running on a single node
• In the simplest use case, it scales up to 600-800k messages per
  second
• But classification, parsing, and filtering still produce several
  tens of thousands of messages per second

Community

• syslog-ng is developed by a community of volunteers, the best way to
  contact us is via our github project page
  project, our gitter channel or
  our mailing list.
• syslog-ng is integrated into almost all Linux distributions and BSDs, it
  is also incorporated into a number of products, see our powered by
  syslog-ng page for more details.

Sponsors

• Balabit is the original commercial sponsor of the syslog-ng project, and was acquired by One Identity in 2018. One Identity offers a commercial edition for syslog-ng, called the syslog-ng Premium Edition.
• Axoflow is the company of Balazs Scheidler, the original creator and main developer of syslog-ng.

Feedback

We are really interested to see who uses our software, so if you do use it and you like
what you see, please tell us about it. A star on github or an email
saying thanks means a lot already, but telling us about your use case,
your experience, and things to improve would be much appreciated.

Just send an email to feedback (at) syslog-ng.org.

Feedback Powers Open Source.

Installation from source

Releases and precompiled tarballs are available on GitHub.

To compile from source, the easiest is to use dbld, a docker based,
self-hosted compile/build/release infrastructure within the source tree. See
dbld/README.md for more information.

For the brave souls who want to compile syslog-ng from scratch, the usual
drill applies:

$ ./configure && make && make install

The extra effort in contrast with the dbld based build is the need to fetch
and install all build dependencies of syslog-ng (of which there are a few).

If you don’t have a configure script (because of cloning from git, for example),
run ./autogen.sh to generate it.

Some of the functionality of syslog-ng is compiled only if the required
development libraries are present. The configure script displays a
summary of enabled features at the end of its run.
For details, see the syslog-ng compiling instructions.

Installation from binaries

Binaries are available in various Linux distributions and contributors
maintain packages of the latest and greatest syslog-ng version for
various OSes.

Debian/Ubuntu

Simply invoke the following command as root:

# apt install syslog-ng

The latest versions of syslog-ng are available for a wide range of Debian
and Ubuntu releases from our APT repository.

The packages and the APT repository are provided “as is” without warranty of any kind, on a best-effort level.

Supported distributions

syslog-ng packages are released for the following distribution versions (x86-64):

Distro version	sources.list component name
Ubuntu 24.04	ubuntu-noble
Ubuntu 23.10	ubuntu-mantic
Ubuntu 23.04	ubuntu-lunar
Ubuntu 22.04	ubuntu-jammy
Ubuntu 20.04	ubuntu-focal
Debian 12	debian-bookworm
Debian 11	debian-bullseye
Debian Unstable	debian-sid
Debian Testing	debian-testing

Adding the APT repository

1. Download and install the release signing key:

   wget -qO - https://ose-repo.syslog-ng.com/apt/syslog-ng-ose-pub.asc | sudo apt-key add -
   

2. Add the repository containing the latest build of syslog-ng to the APT sources. For example, stable releases on Ubuntu 22.04:

   echo "deb https://ose-repo.syslog-ng.com/apt/ stable ubuntu-noble" | sudo tee -a /etc/apt/sources.list.d/syslog-ng-ose.list
   

3. Run apt update

Nightly builds

Nightly packages are built and released from the git master branch everyday.

Use nightly instead of stable in step 2 to use the nightly APT repository. E.g.:

echo "deb https://ose-repo.syslog-ng.com/apt/ nightly ubuntu-noble" | sudo tee -a /etc/apt/sources.list.d/syslog-ng-ose.list

Nightly builds can be used for testing purposes (obtaining new features and bugfixes) at the risk of breakage.

Arch Linux

# pacman -S syslog-ng

Fedora

syslog-ng is available as a Fedora package that you can install using
dnf:

dnf install syslog-ng

You can download packages for the latest versions from here.

For instructions on how to install syslog-ng on RPM distributions, see the blog post Installing latest syslog-ng on RHEL and other RPM distributions.

If you wish to install the latest RPM package that comes from a recent commit in Git for testing purposes, read the blog post, RPM packages from syslog-ng Git HEAD.

macOS

# brew install syslog-ng

Others

Binaries for other platforms are listed on the
official third party page.

Installation from Docker image

Binaries are also available as a Docker image. To find out more, check out the blog post, Your central log server in Docker.

Documentation

For the latest, markdown based version, see the syslog-ng documentation center.
The official documentation of the earlier versions (3.X) of syslog-ng Open Source Edition provided by One Identity is available
here.

Contributing

If you would like to contribute to syslog-ng, to fix a bug or create a new module, the syslog-ng pages helps you take the first steps to working with the code base.