syslog-ng Premium Edition 7.0.14 - Administration Guide

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

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 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.

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

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

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

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

@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);
};

@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);
};

• To install the software required for the elasticsearch2 destination, see Prerequisites.

• For details on how the elasticsearch2 destination works, see How syslog-ng PE interacts with Elasticsearch.

• For the list of options, see Elasticsearch2 destination options (DEPRECATED).

Prerequisites

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

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.