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syslog-ng Open Source Edition 3.38 - 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 kubernetes: Collecting and parsing the Kubernetes CRI (Container Runtime Interface) format linux-audit: Collecting messages from Linux audit logs mqtt: receiving messages from an MQTT broker 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 discord: Sending alerts and notifications to Discord 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-c(): Publishing messages to Apache Kafka using the librdkafka client (C implementation) loggly: Using Loggly logmatic: Using Logmatic.io mongodb(): Storing messages in a MongoDB database mqtt() destination: sending messages from a local network to an MQTT broker 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 Sumo Logic destinations: sumologic-http() and sumologic-syslog() 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
Parsing syslog messages Parsing messages with comma-separated and similar values Parsing key=value pairs JSON parser XML parser Parsing dates and timestamps Python parser Parsing tags Apache access log parser Linux audit parser Cisco parser Parsing enterprise-wide message model (EWMM) messages iptables parser Netskope parser panos-parser(): parsing PAN-OS log messages Sudo parser MariaDB parser Websense parser Fortigate parser Check Point Log Exporter parser Regular expression (regexp) parser 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 The syslog-ng Open Source Edition Documentation License Glossary

Loading modules

The syslog-ng Open Source Edition application loads every available module during startup.

To load a module that is not loaded automatically, include the following statement in the syslog-ng OSE configuration file:

@module <module-name>

Note the following points about the @module statement:

  • The @module statement is a top-level statement, that is, it cannot be nested into any other statement. It is usually used immediately after the @version statement.

  • Every @module statement loads a single module: loading multiple modules requires a separate @module statement for every module.

  • In the configuration file, the @module statement of a module must be earlier than the module is used.

NOTE: To disable loading every module automatically, set the autoload-compiled-modules global variable to 0 in your configuration file:

@define autoload-compiled-modules 0

Note that in this case you have to explicitly load the modules you want to use.

Use the @requires statement to ensure that the specified module is loaded

To ensure that a module is loaded, include the following statement in the syslog-ng OSE configuration file or the external files included in the configuration file:

@requires <module-name>

NOTE: If you include the @requires statement in the:

  • syslog-ng OSE configuration file, syslog-ng OSE attempts to load the required module. If it fails to load the module, syslog-ng OSE stops and an error message is displayed.
  • external files included in the configuration file, syslog-ng OSE attempts to load the required module. If it fails to load the module, only the external file is not processed.

Note that this is not true for modules marked as mandatory. You can make a dependency module mandatory by defining an error message after the @requires <module-name> statement, for example:

@requires http "The http() driver is required for elasticsearch-http(). Install syslog-ng-mod-http to continue."

Listing configuration options

Starting with syslog-ng OSE 3.25, you can use the syslog-ng-cfg-db.py utility to list the available options of configuration objects. For example, you can list all the options that can be set in the file source, and so on.

The syslog-ng-cfg-db.py utility has the following options:

  • The following command lists the contexts that the utility supports.
    syslog-ng-cfg-db.py

    NOTE: Currently, sources and destinations are supported.

  • The following command lists the available drivers of a context:
    syslog-ng-cfg-db.py -c <source|destination>
  • The following command lists the available options of a specific driver and specifies the context and the driver:
    syslog-ng-cfg-db.py -c <source|destination> -d <driver>

    For example, to list the options of the kafka-c() destination driver:

    syslog-ng-cfg-db.py -c destination -d kafka-c

    The output includes the available options of the driver in alphabetical order, and the type of the option. For example:

    destination kafka-c(
        bootstrap-servers/kafka-bootstrap-servers(<string>)
        client-lib-dir(<string>)
        config/option()
        config/option(<string> <arrow> <string-or-number>)
        config/option(<string> <string-or-number>)
        flush-timeout-on-reload(<number>)
        flush-timeout-on-shutdown(<number>)
        frac-digits(<number>)
        key(<string>)
        local-time-zone/time-zone(<string>)
        log-fifo-size(<number>)
        message/template(<string>)
        on-error(<string>)
        persist-name(<string>)
        poll-timeout(<number>)
        properties-file(<path>)
        send-time-zone(<string>)
        sync-send(<yesno>)
        throttle(<number>)
        time-zone(<string>)
        topic(<string>)
        ts-format(<string>)
        workers(<number>)
        config/option(
            <string>(<string-or-number>)
        )
        key(
            <identifier>(<string>)
        )
        message/template(
            <identifier>(<string>)
        )
    )

    NOTE: The script caches the list of the options, so if you want to rebuild the database, you have to use the -r option.

Visualize the configuration

Starting with syslog-ng OSE 3.25, you can visualize the configuration of a running syslog-ng OSE instance using the syslog-ng-ctl --export-config-graph command. The command walks through the effective configuration, and exports it as a graph into a JSON structure.

The resulting JSON file can be converted into DOT file format that visualization tools (for example, Graphviz) can use. The package includes a Python script to convert the exported JSON file into DOT format: <syslog-ng-installation-directory>/contrib/scripts/config-graph-json-to-dot.py

You can convert the DOT file into PNG or PDF format using external tools.

Managing complex syslog-ng configurations

The following sections describe some methods that can be useful to simplify the management of large-scale syslog-ng installations.

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