Chat now with support
Chat with Support

NOTICE! We are upgrading our support telephone services, implementing Genesys, starting the week of May 19, 2025

syslog-ng Open Source Edition 3.26 - Administration Guide

Preface Introduction to syslog-ng The concepts of syslog-ng Installing syslog-ng The syslog-ng OSE quick-start guide The syslog-ng OSE configuration file source: Read, receive, and collect log messages
How sources work default-network-drivers: Receive and parse common syslog messages internal: Collecting internal messages file: Collecting messages from text files wildcard-file: Collecting messages from multiple text files linux-audit: Collecting messages from Linux audit logs network: Collecting messages using the RFC3164 protocol (network() driver) nodejs: Receiving JSON messages from nodejs applications mbox: Converting local email messages to log messages osquery: Collect and parse osquery result logs pipe: Collecting messages from named pipes pacct: Collecting process accounting logs on Linux program: Receiving messages from external applications python: writing server-style Python sources python-fetcher: writing fetcher-style Python sources snmptrap: Read Net-SNMP traps sun-streams: Collecting messages on Sun Solaris syslog: Collecting messages using the IETF syslog protocol (syslog() driver) system: Collecting the system-specific log messages of a platform systemd-journal: Collecting messages from the systemd-journal system log storage systemd-syslog: Collecting systemd messages using a socket tcp, tcp6, udp, udp6: Collecting messages from remote hosts using the BSD syslog protocol— OBSOLETE unix-stream, unix-dgram: Collecting messages from UNIX domain sockets stdin: Collecting messages from the standard input stream
destination: Forward, send, and store log messages
amqp: Publishing messages using AMQP collectd: sending metrics to collectd elasticsearch2: Sending messages directly to Elasticsearch version 2.0 or higher (DEPRECATED) elasticsearch-http: Sending messages to Elasticsearch HTTP Bulk API file: Storing messages in plain-text files graphite: Sending metrics to Graphite Sending logs to Graylog hdfs: Storing messages on the Hadoop Distributed File System (HDFS) Posting messages over HTTP http: Posting messages over HTTP without Java kafka: Publishing messages to Apache Kafka (Java implementation) kafka: Publishing messages to Apache Kafka (C implementation, using the librdkafka client) loggly: Using Loggly logmatic: Using Logmatic.io mongodb: Storing messages in a MongoDB database network: Sending messages to a remote log server using the RFC3164 protocol (network() driver) osquery: Sending log messages to osquery's syslog table pipe: Sending messages to named pipes program: Sending messages to external applications pseudofile() python: writing custom Python destinations redis: Storing name-value pairs in Redis riemann: Monitoring your data with Riemann slack: Sending alerts and notifications to a Slack channel smtp: Generating SMTP messages (email) from logs snmp: Sending SNMP traps Splunk: Sending log messages to Splunk sql: Storing messages in an SQL database stomp: Publishing messages using STOMP syslog: Sending messages to a remote logserver using the IETF-syslog protocol syslog-ng(): Forward logs to another syslog-ng node tcp, tcp6, udp, udp6: Sending messages to a remote log server using the legacy BSD-syslog protocol (tcp(), udp() drivers) Telegram: Sending messages to Telegram unix-stream, unix-dgram: Sending messages to UNIX domain sockets usertty: Sending messages to a user terminal: usertty() destination Write your own custom destination in Java or Python Client-side failover
log: Filter and route log messages using log paths, flags, and filters Global options of syslog-ng OSE TLS-encrypted message transfer template and rewrite: Format, modify, and manipulate log messages parser: Parse and segment structured messages db-parser: Process message content with a pattern database (patterndb) Correlating log messages Enriching log messages with external data Statistics of syslog-ng Multithreading and scaling in syslog-ng OSE Troubleshooting syslog-ng Best practices and examples The syslog-ng manual pages Creative Commons Attribution Non-commercial No Derivatives (by-nc-nd) License Glossary

Dynamic flow-control

Version 3.22 of syslog-ng Open Source Edition includes the following main features.

Starting with version 3.22, syslog-ng OSE uses the log-iw-size() option to allocate a static message window to every flow-controlled log path using the network() and syslog() drivers. In addition, you can configure a dynamic memory buffer that syslog-ng OSE can use to dynamically increase the message window of flow-controlled log paths that have higher traffic. This can be useful in low-memory environments, where only a small subset of the active clients sends messages at high rate.

As a result of these changes the log-fifo-size() option only affects log paths that are not flow-controlled. It is expected that after configuring the dynamic message window, you can decrease the value of log-fifo-size(). For details, see .

 Caution:

Flow control and the log-fifo-size() option works differently starting with syslog-ng OSE 3.22 to avoid dropping flow-controlled messages when log-fifo-size() is misconfigured. From now on, log-fifo-size() only affects log paths that are not flow-controlled. (Flow-controlled log paths have a file destination, or have the flags(flow-control) option set.)

The new behavior is automatically enabled when you update your the @version string in your configuration file. Consider lowering the value of log-fifo-size() option after updating the @version string. For details, see .

SNMP destination

You can now send SNMP traps directly from syslog-ng OSE using the snmp() destination driver. For details, see .

Dynamic template function

A new template function called template can resolve static and dynamic templates in template functions. For example, the name of the template to be invoked can be extracted from the message, or from a name-value pair set using the add-contextual-data() feature. For details, see .

Floating point calculations and numerical template functions

Numerical template functions can now handle floating-point numbers. For details, see the ceil, floor, numerical operations, and round template functions.

Enhancements

  • HTTP-based destinations can now accept multiple URLs in various formats.

  • The message rate of the loggen command can be changed while loggen is running. Send SIGUSR1 to double the message rate, or SIGUSR2 to halve it, for example: kill -USR1 <loggen-pid>

  • The Check Point Log Exporter parser can now parse Check Point log messages in the Splunk format. For details, see .

  • New constants are available in the fetch method of the Python source. For details, see .

  • Global option can be defined in reusable blocks. For details, see .

  • The date-parser() now supports microseconds (%f). For details, see .

  • The value of add-contextual-data() selectors can be a template or a template function, not only a string. For details, see .

Related Documents

The document was helpful.

Select Rating

I easily found the information I needed.

Select Rating