syslog-ng Premium Edition 7.0.14 - 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 linux-audit: Collecting messages from Linux audit logs 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
elasticsearch2: Sending messages directly to Elasticsearch version 2.0 or higher (DEPRECATED) elasticsearch-http: Sending messages to Elasticsearch HTTP Event Collector 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 stackdriver: Sending logs to the Google Stackdriver cloud 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) 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

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.

Metrics and counters of syslog-ng PE

You can list all active metrics on your syslog-ng PE host using the following command (this lists the metrics, without their current values): syslog-ng-ctl query list "*"

To list the metrics and their values, use the following command: syslog-ng-ctl query get "*"

The displayed metrics have the following structure.

  1. The type of the object (for example dst.file, tag, src.facility)

  2. The ID of the object used in the syslog-ng configuration file, for example d_internal or source.src_tcp. The #0 part means that this is the first destination in the destination group.

  3. The instance ID (destination) of the object, for example the filename of a file destination, or the name of the application for a program source or destination.

  4. The status of the object. One of the following:

    • a - active. At the time of quering the statistics, the source or the destination was still alive (it continuously received statistical data).

    • d - dynamic. Such objects may not be continuously available, for example, like statistics based on the sender's hostname. These counters only appear above a certain value of stats-level() global option:

      • host: source host, from stats-level(2)

      • sender: sender host, from stats-level(3)

      • program: program, from stats-level(3)

      Example: Dynamic counters

      The following example contains 6 different dynamic values: a sender, a host, and four different programs.

      src.sender;;localhost;d;processed;4
      src.sender;;localhost;d;stamp;1509121934
      src.program;;P-18069;d;processed;1
      src.program;;P-18069;d;stamp;1509121933
      src.program;;P-21491;d;processed;1
      src.program;;P-21491;d;stamp;1509121934
      src.program;;P-9774;d;processed;1
      src.program;;P-9774;d;stamp;1509121919
      src.program;;P-14737;d;processed;1
      src.program;;P-14737;d;stamp;1509121931
      src.host;;localhost;d;processed;4
      src.host;;localhost;d;stamp;1509121934

      To avoid performance issues or even overloading syslog-ng PE, you might want to limit the number of registered dynamic counters in the message statistics. To do this, configure the stats-max-dynamics() global option.

    • o - This object was once active, but stopped receiving messages. (For example a dynamic object may disappear and become orphan.)

      NOTE:

      The syslog-ng PE application stores the statistics of the objects when syslog-ng PE is reloaded. However, if the configuration of syslog-ng PE was changed since the last reload, the statistics of orphaned objects are deleted.

  5. The type of the statistics:

    • processed: The number of messages that successfully reached their destination driver. Note that this does not necessarily mean that the destination driver successfully delivered the messages (for example, written to disk or sent to a remote server).

    • dropped: The number of dropped messages — syslog-ng PE could not send the messages to the destination and the output buffer got full, so messages were dropped by the destination driver, or syslog-ng PE dropped the message for some other reason (for example, a parsing error).

    • queued: The number of messages passed to the message queue of the destination driver, waiting to be sent to the destination.

    • suppressed: The number of suppressed messages (if the suppress() feature is enabled).

    • stamp: The UNIX timestamp of the last message sent to the destination.

    • discarded: The number of messages discarded by the given parser. These are messages that the parser could not parsed, and are therefore not processed. For example:

      parser;demo_parser;;a;discarded;20
    • memory_usage: The memory used by the messages in the different queue types (in bytes). This includes every queue used by the object, including memory buffers (log-fifo) and disk-based buffers (both reliable and non-reliable). For example:

      dst.network;d_net#0;tcp,127.0.0.1:9999;a;memory_usage;0

      Note that the memory usage (size) of queues does not equal to the memory usage (size) of the log messages in syslog-ng PE. A log message can be in multiple queues, thus its size is added to multiple queue sizes. To check the size of all log messages, use global.msg_allocated_bytes.value metric.

    • matched: The number of messages that are accepted by a given filter. Available for filters and similar objects (for example, a conditional rewrite rule). For example, if a filter matches a specific hostname, then the matched counter contains the number of messages that reached the filter from this hosts.

      filter;demo_filter;;a;matched;28
    • not_matched: The number of messages that are filtered out by a given filter. Available for filters and similar objects (for example, a conditional rewrite rule). For example, if a filter matches a specific hostname, then the not_matched counter contains the number of messages that reached the filter from other hosts, and so the filter discarded them. Note that since the not_matched metric applies to filters, and filters are expected to discard messages that do not match the filter condition, not_matched messages are not included in the dropped metric of other objects.

      filter;demo_filter;;a;not_matched;0
    • written: The number of messages successfully delivered to the destination. This value is calculated from other counters: written = processed - queued - dropped. That is, the number of messages syslog-ng PE passed to the destination driver (processed) minus the number of messages that are still in the output queue of the destination driver (queued) and the number of messages dropped because of an error (dropped, for example, because syslog-ng PE could not deliver the message to the destination and exceeded the number of retries).

      This metric is calculated from other metrics. You cannot reset this metric directly: to reset it, you have to reset the metrics it is calculated from.

  6. The number of such messages.

Availability of statistics

Certain statistics are available only if the stats-level() global option is set to a higher value.

  • Level 0 collects only statistics about the sources and destinations.

  • Level 1 contains details about the different connections and log files, but has a slight memory overhead.

  • Level 2 contains detailed statistics based on the hostname.

  • Level 3 contains detailed statistics based on various message parameters like facility, severity, or tags.

When receiving messages with non-standard facility values (that is, higher than 23), these messages will be listed as other facility instead of their facility number.

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