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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

elasticsearch2: Sending messages directly to Elasticsearch version 2.0 or higher (DEPRECATED)

Caution:

This destination is deprecated and will be removed from a future version of syslog-ng PE. We recommend using the elasticsearch-http: Sending messages to Elasticsearch HTTP Event Collector destination instead.

Starting with version 5.6 of syslog-ng PE can directly send log messages to Elasticsearch, allowing you to search and analyze your data in real time, and visualize it with Kibana.

NOTE:

In order to use this destination, syslog-ng Premium Edition must run in server mode. Typically, only the central syslog-ng Premium Edition server uses this destination. For details on the server mode, see Server mode.

Note the following limitations when using the syslog-ng PE elasticsearch2 destination:

  • This destination is only supported on the Linux platforms that use the linux glibc2.11 installer, including: Red Hat ES 7, Ubuntu 14.04 (Trusty Tahr).

  • Since syslog-ng PE uses Java libraries, the elasticsearch2 destination has significant memory usage.

  • The log messages of the underlying client libraries are available in the internal() source of syslog-ng PE.

Declaration
@module mod-java
@include "scl.conf"

elasticsearch2(
    index("syslog-ng_${YEAR}.${MONTH}.${DAY}")
    type("test")
    cluster("syslog-ng")
);
Example: Sending log data to Elasticsearch version 2.x and above

The following example defines an elasticsearch2 destination that sends messages in transport mode to an Elasticsearch server running on the localhost, using only the required parameters.

@module mod-java
@include "scl.conf"

destination d_elastic {
    elasticsearch2(
        index("syslog-ng_${YEAR}.${MONTH}.${DAY}")
        type("test")
    );
};

The following example sends 10000 messages in a batch, in transport mode, and includes a custom unique ID for each message.

@module mod-java
@include "scl.conf"

options {
    threaded(yes);
    use-uniqid(yes);
};

source s_syslog {
    syslog();
};

destination d_elastic {
    elasticsearch2(
        index("syslog-ng_${YEAR}.${MONTH}.${DAY}")
        type("test")
        cluster("syslog-ng")
        client-mode("transport")
        custom-id("${UNIQID}")
        flush-limit("10000")
    );
};

log {
    source(s_syslog);
    destination(d_elastic);
    flags(flow-control);
};

The following example send messages to Elasticsearch over HTTP using its REST API:

@include "scl.conf"

source s_network {
    network(port(5555));
};

destination d_elastic {
    elasticsearch2(
        client-mode("http")
        cluster("es-syslog-ng")
        index("x201")
        cluster-url("http://192.168.33.10:9200")
        type("slng_test_type")
        flush-limit("0")
    );
};

log {
    source(s_network);
    destination(d_elastic);
    flags(flow-control);
};

NOTE:

If you delete all Java destinations from your configuration and reload syslog-ng, the JVM is not used anymore, but it is still running. If you want to stop JVM, stop syslog-ng and then start syslog-ng again.

Prerequisites

The following describes how to send messages from syslog-ng PE to Elasticsearch.

To send messages from syslog-ng PE to Elasticsearch

  1. Download and install the Java Runtime Environment (JRE), 2.x (or newer). The syslog-ng PE elasticsearch2 destination is tested and supported when using the Oracle implementation of Java. Other implementations are untested and unsupported, they may or may not work as expected.

  2. NOTE:

    This step is only required if you use the elasticsearch2 destination in node mode or transport mode.

    Download the Elasticsearch libraries (version 2.x or newer from the 2.x line) from https://www.elastic.co/downloads/elasticsearch.One Identity tests the destination using Elasticsearch version 2.4.

  3. NOTE:

    This step is only required if you use the elasticsearch2 destination in node mode or transport mode.

    Extract the Elasticsearch libraries into a temporary directory, then collect the various .jar files into a single directory (for example, /opt/elasticsearch/lib/) where syslog-ng PE can access them. You must specify this directory in the syslog-ng PE configuration file. The files are located in the lib directory and its subdirectories of the Elasticsearch release package.

How syslog-ng PE interacts with Elasticsearch

The syslog-ng PE application sends the log messages to the official Elasticsearch client library, which forwards the data to the Elasticsearch nodes. The way how syslog-ng PE interacts with Elasticsearch is described in the following steps.

  • After syslog-ng PE is started and the first message arrives to the elasticsearch2 destination, the elasticsearch2 destination tries to connect to the Elasticsearch server or cluster. If the connection fails, syslog-ng PE will repeatedly attempt to connect again after the period set in time-reopen() expires.

  • If the connection is established, syslog-ng PE sends JSON-formatted messages to Elasticsearch.

    • If flush-limit is set to 1: syslog-ng PE sends the message reliably: it sends a message to Elasticsearch, then waits for a reply from Elasticsearch. In case of failure, syslog-ng PE repeats sending the message, as set in the retries() parameter. If sending the message fails for retries() times, syslog-ng PE drops the message.

      This method ensures reliable message transfer, but is slow (about 1000 messages/second).

    • If flush-limit is higher than 1: syslog-ng PE sends messages in a batch, and receives the response asynchronously. In case of a problem, syslog-ng PE cannot resend the messages.

      This method is relatively fast (depending on the size of flush-limit, about 8000 messages/second), but the transfer is not reliable. In transport mode, over 5000-30000 messages can be lost before syslog-ng PE recognizes the error. In node mode, about 1000 messages can be lost.

    • If concurrent-requests is higher than 1, syslog-ng PE can send multiple batches simultaneously, increasing performance (and also the number of messages that can be lost in case of an error). For details, see concurrent-requests().

  • Version 7.0.3 and newer of syslog-ng PE automatically converts the timestamp (date) of the message to UTC, as needed by Elasticsearch and Kibana.

Client modes

The syslog-ng PE application can interact with Elasticsearch in the following modes of operation: node, and transport.

  • Transport mode

    The syslog-ng PE application uses the transport client API of Elasticsearch, and uses the server(), port(), and cluster() options from the syslog-ng PE configuration file.

  • Node mode

    The syslog-ng PE application acts as an Elasticsearch node (client no-data), using the node client API of Elasticsearch. Further options for the node can be describe in an Elasticsearch configuration file specified in the resource() option.

    NOTE:

    In Node mode, it is required to define the home of the elasticsearch installation with the path.home parameter in the .yml file. For example: path.home: /usr/share/elasticsearch.

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