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syslog-ng Premium Edition 7.0.12 - Administration Guide

Preface Introduction to syslog-ng The concepts of syslog-ng Installing syslog-ng The syslog-ng PE quick-start guide The syslog-ng PE configuration file Collecting log messages — sources and source drivers
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 network: Collecting messages using the RFC3164 protocol (network() driver) osquery: Collect and parse osquery result logs pipe: Collecting messages from named pipes 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 unix-stream, unix-dgram: Collecting messages from UNIX domain sockets windowsevent: Collecting Windows event logs
Sending and storing log messages — destinations and destination drivers
elasticsearch: Sending messages directly to Elasticsearch version 1.x elasticsearch2: Sending messages directly to Elasticsearch version 2.0 or higher file: Storing messages in plain-text files hdfs: Storing messages on the Hadoop Distributed File System (HDFS) http: Posting messages over HTTP kafka: Publishing messages to Apache Kafka logstore: Storing messages in encrypted files mongodb: Storing messages in a MongoDB database network: Sending messages to a remote log server using the RFC3164 protocol (network() driver) pipe: Sending messages to named pipes program: Sending messages to external applications python: writing custom Python destinations smtp: Generating SMTP messages (e-mail) from logs splunk-hec: Sending messages to Splunk HTTP Event Collector sql: Storing messages in an SQL database syslog: Sending messages to a remote logserver using the IETF-syslog protocol syslog-ng: Forwarding messages and tags 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) unix-stream, unix-dgram: Sending messages to UNIX domain sockets usertty: Sending messages to a user terminal — usertty() destination Client-side failover
Routing messages: log paths, flags, and filters Global options of syslog-ng PE TLS-encrypted message transfer Advanced Log Transfer Protocol Reliability and minimizing the loss of log messages Manipulating messages parser: Parse and segment structured messages Processing message content with a pattern database Correlating log messages Enriching log messages with external data Monitoring statistics and metrics of syslog-ng Multithreading and scaling in syslog-ng PE Troubleshooting syslog-ng Best practices and examples The syslog-ng manual pages About us

Options add-contextual-data()

The add-contextual-data() has the following options.

Required options:

The following options are required: selector(), database().

database()
Type: <path-to-file>.csv
Default:

Description: Specifies the path to the CSV file, for example, /opt/syslog-ng/my-csv-database.csv. The extension of the file must be .csv, and can include Windows-style (CRLF) or UNIX-style (LF) linebreaks. You can use absolute path, or relative to the syslog-ng PE binary.

default-selector()
Synopsis: default-selector()

Description: Specifies the ID of the entry (line) that is corresponds to log messages that do not have a selector that matches an entry in the database. For example, if you add name-value pairs from the database based on the hostname from the log message (selector("${HOST}")), then you can include a line for unknown hosts in the database, and set default-selector() to the ID of the line for unknown hosts. In the CSV file:

unknown-hostname,host-role,unknown

In the syslog-ng PE configuration file:

add-contextual-data(
    selector("$HOST")
    database("context-info-db.csv")
    default-selector("unknown-hostname")
);
prefix()
Synopsis: prefix()

Description: Insert a prefix before the name part of the added name-value pairs (including the pairs added by the default-selector()) to help further processing.

selector()
Synopsis: selector()

Description: Specifies the string or macro that syslog-ng PE evaluates for each message, and if its value matches the ID of an entry in the database, syslog-ng PE adds the name-value pair of every matching database entry to the log message. Currently, you can use strings and a single macro (for example, ${HOST}) in the selector() option, templates are not supported. To use filters as selectors, see Using filters as selector.

Looking up GeoIP2 data from IP addresses

The syslog-ng PE application can lookup IP addresses from an offline GeoIP2 database, and make the retrieved data available in name-value pairs. Depending on the database used, you can access country code, longitude, and latitude information and so on.

The syslog-ng PE application works with the Country and the City version of the GeoIP2 database, both free and the commercial editions. The syslog-ng PE application works with the mmdb (GeoIP2) format of these databases. Other formats, like csv are not supported.

NOTE:

To access longitude and latitude information, download the City version of the GeoIP2 database.

There are two types of GeoIP2 databases available.

  • GeoLite2 City:

    • free of charge

    • less accurate

  • GeoIP2 City:

    • has to be purchased

    • more accurate

Unzip the downloaded database (for example, to the /usr/share/GeoIP2/GeoIP2City.mmdb file). This path will be used later in the configuration.

Options of geoip2 parsers

The geoip2 parser has the following options.

prefix()
Synopsis: prefix()

Description: Insert a prefix before the name part of the parsed name-value pairs to help further processing. For example:

  • To insert the my-parsed-data. prefix, use the prefix(my-parsed-data.) option.

  • To refer to a particular data that has a prefix, use the prefix in the name of the macro, for example, ${my-parsed-data.name} .

  • If you forward the parsed messages using the IETF-syslog protocol, you can insert all the parsed data into the SDATA part of the message using the prefix(.SDATA.my-parsed-data.) option.

Names starting with a dot (for example, .example) are reserved for use by syslog-ng PE. If you use such a macro name as the name of a parsed value, it will attempt to replace the original value of the macro (note that only soft macros can be overwritten, see Hard vs. soft macros for details). To avoid such problems, use a prefix when naming the parsed values, for example, prefix(my-parsed-data.)

For example, to insert the .geoip2 prefix, use the prefix(.geoip2) option. To refer to a particular data when using a prefix, use the prefix in the name of the macro, for example, ${geoip2.country_code} .

database()
Synopsis: database()
Default:

Description: Path to the GeoIP2 database to use. This works with absolute and relative paths as well. Note that syslog-ng PE must have the required privileges to read this file. Do not modify or delete this file while syslog-ng PE is running, it can crash syslog-ng PE.

Monitoring statistics and metrics of syslog-ng

The syslog-ng PE application collects various statistics and measures different metrics about the messages it receives and delivers. These metrics are collected into different counters, depending on the configuration of syslog-ng PE. The stats-level() global option determines exactly which statistics syslog-ng PE collects. You can access these statistics and metrics using the following methods.

Recommended: Structured, selective methods:
Legacy: Unstructured, bulk methods:
  • Using the internal() source.

  • Using the syslog-ng-ctl stats command.

  • Use the socat application: echo STATS | socat -vv UNIX-CONNECT:/opt/syslog-ng/var/run/syslog-ng.ctl -

  • If you have an OpenBSD-style netcat application installed, use the echo STATS | nc -U /opt/syslog-ng/var/run/syslog-ng.ctl command. Note that the netcat included in most Linux distributions is a GNU-style version that is not suitable to query the statistics of syslog-ng.

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