syslog-ng Open Source Edition 3.25 - Administration Guide

collectd: sending metrics to collectd

The collectd() destination uses the unixsock plugin of the collectd application to send log messages to the collectd system statistics collection daemon. You must install and configure collectd separately before using this destination.

Available in syslog-ng OSE version 3.20 and later.

collectd();

destination d_collectd {
  collectd(
    socket("<path-to-collectd-socket>"),
    host("${HOST}"),
    plugin("${PROGRAM}"),
    type("<type-of-the-collected-metric>"),
    values("<metric-sent-to-collectd>"),
  );
};

destination d_collectd {
  collectd(
    socket("/var/run/collectd-unixsock"),
    host("${HOST}"),
    plugin("${PROGRAM}"),
    type("gauge"),
    type_instance("seqnum"),
    values("${SEQNUM}"),
  );
};

To use the collectd() driver, the scl.conf file must be included in your syslog-ng OSE configuration:

@include "scl.conf"

The collectd() driver is actually a reusable configuration snippet configured to send log messages using the unix-stream() driver. For details on using or writing such configuration snippets, see Reusing configuration blocks. You can find the source of this configuration snippet on GitHub.

collectd() destination options

The collectd() destination has the following options. The plugin() and type() options are required options. You can also set other options of the underlying unix-stream() driver (for example, socket buffer size).

disk-buffer()

Description: This option enables putting outgoing messages into the disk buffer of the destination to avoid message loss in case of a system failure on the destination side. It has the following options:

Options reliable() and disk-buf-size() are required options.

destination d_demo {
    network(
        "127.0.0.1"
        port(3333)
        disk-buffer(
            mem-buf-size(10000)
            disk-buf-size(2000000)
            reliable(yes)
            dir("/tmp/disk-buffer")
        )
    );
};

destination d_demo {
    network(
        "127.0.0.1"
        port(3333)
           disk-buffer(
            mem-buf-length(10000)
            disk-buf-size(2000000)
            reliable(no)
            dir("/tmp/disk-buffer")
        )
    );
};

flush-lines()

Description: Specifies how many lines are flushed to a destination at a time. The syslog-ng OSE application waits for this number of lines to accumulate and sends them off in a single batch. Increasing this number increases throughput as more messages are sent in a single batch, but also increases message latency.

The syslog-ng OSE application flushes the messages if it has sent flush-lines() number of messages, or the queue became empty. If you stop or reload syslog-ng OSE or in case of network sources, the connection with the client is closed, syslog-ng OSE automatically sends the unsent messages to the destination.

For optimal performance when sending messages to an syslog-ng OSE server, make sure that the value of flush-lines() is smaller than the window size set in the log-iw-size() option in the source of your server.

frac-digits()

Description: The syslog-ng application can store fractions of a second in the timestamps according to the ISO8601 format. The frac-digits() parameter specifies the number of digits stored. The digits storing the fractions are padded by zeros if the original timestamp of the message specifies only seconds. Fractions can always be stored for the time the message was received. Note that syslog-ng can add the fractions to non-ISO8601 timestamps as well.

hook-commands()

Description: This option makes it possible to execute external programs when the relevant driver is initialized or torn down. The hook-commands() can be used with all source and destination drivers with the exception of the usertty() and internal() drivers.

Using the hook-commands() when syslog-ng OSE starts or stops

To execute an external program when syslog-ng OSE starts or stops, use the following options:

Using the hook-commands() when syslog-ng OSE reloads

To execute an external program when the syslog-ng OSE configuration is initiated or torn down, for example, on startup/shutdown or during a syslog-ng OSE reload, use the following options:

source {
   network(transport(udp)
	hook-commands(
          startup("iptables -I LOGCHAIN 1 -p udp --dport 514 -j ACCEPT")
          shutdown("iptables -D LOGCHAIN 1")
        )
     );
};

type("gauge"),

log-fifo-size()

Description: The number of messages that the output queue can store.

keep-alive()

Description: Specifies whether connections to destinations should be closed when syslog-ng is reloaded. Note that this applies to the client (destination) side of the syslog-ng connections, server-side (source) connections are always reopened after receiving a HUP signal unless the keep-alive option is enabled for the source.

plugin("${PROGRAM}"),

type("gauge"),

so-broadcast()

Description: This option controls the SO_BROADCAST socket option required to make syslog-ng send messages to a broadcast address. For details, see the socket(7) manual page.

so-keepalive()

Description: Enables keep-alive messages, keeping the socket open. This only effects TCP and UNIX-stream sockets. For details, see the socket(7) manual page.

so-rcvbuf()

Description: Specifies the size of the socket receive buffer in bytes. For details, see the socket(7) manual page.

so-sndbuf()

Description: Specifies the size of the socket send buffer in bytes. For details, see the socket(7) manual page.

suppress()

Description: If several identical log messages would be sent to the destination without any other messages between the identical messages (for example, an application repeated an error message ten times), syslog-ng can suppress the repeated messages and send the message only once, followed by the Last message repeated n times. message. The parameter of this option specifies the number of seconds syslog-ng waits for identical messages.

throttle()

Description: Sets the maximum number of messages sent to the destination per second. Use this output-rate-limiting functionality only when using disk-buffer as well to avoid the risk of losing messages. Specifying 0 or a lower value sets the output limit to unlimited.

type("gauge"),

type-instance("seqnum"),

values("${SEQNUM}"),

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

Starting with version 3.7 of syslog-ng OSE 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 OSE elasticsearch2 destination:

• This destination is only supported on the Linux platform.

• Since syslog-ng OSE 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 OSE.

@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);
};

destination d_elastic {
    elasticsearch2(
        client-mode("https")
        cluster("es-syslog-ng")
        index("x201")
        cluster-url("http://192.168.33.10:9200")
        type("slng_test_type")
        flush-limit("0")
        http-auth-type("clientcert")
        java-keystore-filepath("<path-to-your-java-keystore>.jks")
        java-keystore-password("password-to-your-keystore")
        java-truststore-filepath("<path-to-your-java-keystore>.jks")
        java-truststore-password("password-to-your-keystore")
    );
};

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

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

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

The elasticsearch2() driver is actually a reusable configuration snippet configured to receive log messages using the Java language-binding of syslog-ng OSE. For details on using or writing such configuration snippets, see Reusing configuration blocks. You can find the source of the elasticsearch configuration snippet on GitHub. For details on extending syslog-ng OSE in Java, see the Getting started with syslog-ng development guide.

Prerequisites

To send messages from syslog-ng OSE to Elasticsearch, complete the following steps.