syslog-ng Premium Edition 7.0.29 - Administration Guide

The hdfs destination stores the log messages in files on the Hadoop Distributed File System (HDFS). The hdfs destination has the following options.

The following options are required: hdfs-file(), hdfs-uri(). Note that to use hdfs, you must add the following lines to the beginning of your syslog-ng PE configuration:

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

disk-buffer()

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

frac-digits()

Description: The syslog-ng PE 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.

hdfs-append-enabled()

Description: When hdfs-append-enabled is set to true, syslog-ng PE will append new data to the end of an already existing HDFS file. Note that in this case, archiving is automatically disabled, and syslog-ng PE will ignore the hdfs-archive-dir option.

When hdfs-append-enabled is set to false, the syslog-ng PE application always creates a new file if the previous has been closed. In that case, appending data to existing files is not supported.

When you choose to write data into an existing file, syslog-ng PE does not extend the filename with a UUID suffix because there is no need to open a new file (a new unique ID would mean opening a new file and writing data into that).

destination d_hdfs_9bf3ff45341643c69bf46bfff940372a {
    hdfs(
        client-lib-dir(/hdfs-libs)
        hdfs-uri("hdfs://hdp2.syslog-ng.example:8020")
        hdfs_file("/var/testdb_working_dir/$DAY-$HOUR.txt")
    );
};

jvm-options()

Description: Specify the Java Virtual Machine (JVM) settings of your Java destination from the syslog-ng PE configuration file.

For example:

jvm-options("-Xss1M -XX:+TraceClassLoading")

You can set this option only as a global option, by adding it to the options statement of the syslog-ng configuration file.

destination d_hdfs {
    hdfs(
        client-lib-dir("/hdfs-libs/lib")
        hdfs-uri("hdfs://hdp-kerberos.syslog-ng.example:8020")
        kerberos-keytab-file("/opt/syslog-ng/etc/hdfs.headless.keytab")
        kerberos-principal("hdfs-hdpkerberos@MYREALM")
        hdfs-file("/var/hdfs/test.log")
    );
};

destination d_hdfs {
    hdfs(
        client-lib-dir("/hdfs-libs/lib")
        hdfs-uri("hdfs://hdp-kerberos.syslog-ng.example:8020")
        kerberos-keytab-file("/opt/syslog-ng/etc/hdfs.headless.keytab")
        kerberos-principal("hdfs-hdpkerberos@MYREALM")
        hdfs-file("/var/hdfs/test.log")
    );
};

log-fifo-size()

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

on-error()

Description: Controls what happens when type-casting fails and syslog-ng PE cannot convert some data to the specified type. By default, syslog-ng PE drops the entire message and logs the error. Currently the value-pairs() option uses the settings of on-error().

• drop-message: Drop the entire message and log an error message to the internal() source. This is the default behavior of syslog-ng PE.

• drop-property: Omit the affected property (macro, template, or message-field) from the log message and log an error message to the internal() source.

• fallback-to-string: Convert the property to string and log an error message to the internal() source.

• silently-drop-message: Drop the entire message silently, without logging the error.

• silently-drop-property: Omit the affected property (macro, template, or message-field) silently, without logging the error.

• silently-fallback-to-string: Convert the property to string silently, without logging the error.

retries()

Description: The number of times syslog-ng PE attempts to send a message to this destination. If syslog-ng PE could not send a message, it will try again until the number of attempts reaches retries(), then drops the message.

template()

Description: Specifies a template defining the logformat to be used in the destination. Macros are described in Macros of syslog-ng PE. Please note that for network destinations it might not be appropriate to change the template as it changes the on-wire format of the syslog protocol which might not be tolerated by stock syslog receivers (like syslogd or syslog-ng itself). For network destinations make sure the receiver can cope with the custom format defined.

throttle()

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

time-zone()

Description: Convert timestamps to the timezone specified by this option. If this option is not set, then the original timezone information in the message is used. Converting the timezone changes the values of all date-related macros derived from the timestamp, for example, HOUR. For the complete list of such macros, see Date-related macros.

The timezone can be specified as using the name of the (for example, time-zone("Europe/Budapest")), or as the timezone offset in +/-HH:MM format (for example, +01:00). On Linux and UNIX platforms, the valid timezone names are listed under the /usr/share/zoneinfo directory.

ts-format()

Description: Override the global timestamp format (set in the global ts-format() parameter) for the specific destination. For details, see ts-format().