Elasticsearch2 destination options (DEPRECATED)

The elasticsearch2 destination can directly send log messages to Elasticsearch, allowing you to search and analyze your data in real time, and visualize it with Kibana. The elasticsearch2 destination has the following options.

Required options:

The following options are required: index(), type(). In node mode, either the cluster() or the resource() option is required as well. Note that to use elasticsearch2, you must add the following lines to the beginning of your AxoSyslog configuration:

   @include "scl.conf"

client-lib-dir()

Description: The list of the paths where the required Java classes are located. For example, class-path("/opt/syslog-ng/lib/syslog-ng/java-modules/:/opt/my-java-libraries/libs/"). If you set this option multiple times in your AxoSyslog configuration (for example, because you have multiple Java-based destinations), AxoSyslog will merge every available paths to a single list.

Description: Include the path to the directory where you copied the required libraries (see Prerequisites), for example, client-lib-dir(/user/share/elasticsearch-2.2.0/lib).

client-mode()

Description: Specifies the client mode used to connect to the Elasticsearch server, for example, client-mode("node").

HTTP mode

The AxoSyslog application sends messages over HTTP using the REST API of Elasticsearch, and uses the cluster-url() and cluster() options from the AxoSyslog configuration file. In HTTP mode, AxoSyslogelasticsearch2 driver can send log messages to every Elasticsearch version, including 1.x-6.x. Note that HTTP mode is available in AxoSyslog version 3.8 and newer.

In version 3.10 and newer, you can list multiple servers in HTTP and HTTPS mode in the cluster-url() and server() options. The AxoSyslog application will use these destination servers in load-balancing fashion. Note that load-balancing is handled by an external library (Jest), AxoSyslog does not have any direct influence on it.

HTTPS mode

The AxoSyslog application sends messages over an encrypted and optionally authenticated HTTPS channel using the REST API of Elasticsearch, and uses the cluster-url() and cluster() options from the AxoSyslog configuration file. In HTTPS mode, AxoSyslogelasticsearch2 driver can send log messages to every Elasticsearch version, including 1.x-6.x. Note that HTTPS mode is available in AxoSyslog version 3.10 and newer.

This mode supports password-based and certificate-based authentication of the client, and can verify the certificate of the server as well.

In version 3.10 and newer, you can list multiple servers in HTTP and HTTPS mode in the cluster-url() and server() options. The AxoSyslog application will use these destination servers in load-balancing fashion. Note that load-balancing is handled by an external library (Jest), AxoSyslog does not have any direct influence on it.

Transport mode

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

Node mode

The AxoSyslog 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.

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

Search Guard mode

Use the Search Guard Elasticsearch plugin to encrypt and authenticate your connections from AxoSyslog to Elasticsearch 2.x. For Elasticsearch versions 5.x and newer, use HTTPS mode. For details on configuring Search Guard mode, see Search Guard.

cluster()

Description: Specifies the name or the Elasticsearch cluster, for example, cluster("my-elasticsearch-cluster"). Optionally, you can specify the name of the cluster in the Elasticsearch resource file. For details, see resource().

cluster-url()

Description: Specifies the URL or the Elasticsearch cluster, for example, cluster-url("http://192.168.10.10:9200")").

In version 3.10 and newer, you can list multiple servers in HTTP and HTTPS mode in the cluster-url() and server() options. The AxoSyslog application will use these destination servers in load-balancing fashion. Note that load-balancing is handled by an external library (Jest), AxoSyslog does not have any direct influence on it.

For example:

   destination d_elasticsearch {
      elasticsearch2(
        client-lib-dir("/usr/share/elasticsearch/lib/")
        index("syslog-${YEAR}.${MONTH}.${DAY}")
        type("syslog")
        time-zone("UTC")
        client-mode("http")
        cluster-url("http://node01:9200 http://node02:9200")
      );
    };

concurrent-requests()

Description: The number of concurrent (simultaneous) requests that AxoSyslog sends to the Elasticsearch server. Set this option to 1 or higher to increase performance. When using the concurrent-requests() option, make sure that the flush-limit() option is higher than one, otherwise it will not have any noticeable effect. For details, see flush-limit().

custom-id()

Description: Use this option to specify a custom ID for the records inserted into Elasticsearch. If this option is not set, the Elasticsearch server automatically generates and ID for the message. For example: custom-id(${UNIQID}) (Note that to use the ${UNIQID} macro, the use-uniqid() global option must be enabled. For details, see use-uniqid().)

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:

capacity-bytes()

Description: This is a required option. The maximum size of the disk-buffer in bytes. The minimum value is 1048576 bytes. If you set a smaller value, the minimum value will be used automatically. It replaces the old log-disk-fifo-size() option.

In AxoSyslog version 4.2 and earlier, this option was called disk-buf-size().

compaction()

Description: If set to yes, AxoSyslog prunes the unused space in the LogMessage representation, making the disk queue size smaller at the cost of some CPU time. Setting the compaction() argument to yes is recommended when numerous name-value pairs are unset during processing, or when the same names are set multiple times.

dir()

Description: Defines the folder where the disk-buffer files are stored.

flow-control-window-bytes()

Description: Use this option if the option reliable() is set to yes. This option contains the size of the messages in bytes that is used in the memory part of the disk buffer. It replaces the old log-fifo-size() option. It does not inherit the value of the global log-fifo-size() option, even if it is provided. Note that this option will be ignored if the option reliable() is set to no.

In AxoSyslog version 4.2 and earlier, this option was called mem-buf-size().

flow-control-window-size()

Description: Use this option if the option reliable() is set to no. This option contains the number of messages stored in overflow queue. It replaces the old log-fifo-size() option. It inherits the value of the global log-fifo-size() option if provided. If it is not provided, the default value is 10000 messages. Note that this option will be ignored if the option reliable() is set to yes.

In AxoSyslog version 4.2 and earlier, this option was called mem-buf-length().

front-cache-size()

Description: The number of messages stored in the output buffer of the destination. Note that if you change the value of this option and the disk-buffer already exists, the change will take effect when the disk-buffer becomes empty.

Options reliable() and capacity-bytes() are required options.

In AxoSyslog version 4.2 and earlier, this option was called qout-size().

prealloc()

Description:

By default, AxoSyslog doesn’t reserve the disk space for the disk-buffer file, since in a properly configured and sized environment the disk-buffer is practically empty, so a large preallocated disk-buffer file is just a waste of disk space. But a preallocated buffer can prevent other data from using the intended buffer space (and elicit a warning from the OS if disk space is low), preventing message loss if the buffer is actually needed. To avoid this problem, when using AxoSyslog 4.0 or later, you can preallocate the space for your disk-buffer files by setting prealloc(yes).

In addition to making sure that the required disk space is available when needed, preallocated disk-buffer files provide radically better (3-4x) performance as well: in case of an outage the amount of messages stored in the disk-buffer is continuously growing, and using large continuous files is faster, than constantly waiting on a file to change its size.

If you are running AxoSyslog on a dedicated host (always recommended for any high-volume settings), use prealloc(yes).

Available in AxoSyslog 4.0 and later.

reliable()

Description: If set to yes, AxoSyslog cannot lose logs in case of reload/restart, unreachable destination or AxoSyslog crash. This solution provides a slower, but reliable disk-buffer option. It is created and initialized at startup and gradually grows as new messages arrive. If set to no, the normal disk-buffer will be used. This provides a faster, but less reliable disk-buffer option.

truncate-size-ratio()

Description: Limits the truncation of the disk-buffer file. Truncating the disk-buffer file can slow down the disk IO operations, but it saves disk space. By default, AxoSyslog version 4.0 and later doesn’t truncate disk-buffer files by default (truncate-size-ratio(1)). Earlier versions freed the disk-space when at least 10% of the disk-buffer file could be freed (truncate-size-ratio(0.1)).

AxoSyslog only truncates the file if the possible disk gain is more than truncate-size-ratio() times capacity-bytes().

• Smaller values free disk space quicker.
• Larger ratios result in better performance.

If you want to avoid performance fluctuations:

• use truncate-size-ratio(1) (never truncate), or
• use prealloc(yes) to reserve the entire size of the disk-buffer on disk.

Example: Examples for using disk-buffer()

In the following case reliable disk-buffer() is used.

   destination d_demo {
        network(
            "127.0.0.1"
            port(3333)
            disk-buffer(
                flow-control-window-bytes(10000)
                capacity-bytes(2000000)
                reliable(yes)
                dir("/tmp/disk-buffer")
            )
        );
    };

In the following case normal disk-buffer() is used.

   destination d_demo {
        network(
            "127.0.0.1"
            port(3333)
               disk-buffer(
                flow-control-window-size(10000)
                capacity-bytes(2000000)
                reliable(no)
                dir("/tmp/disk-buffer")
            )
        );
    };

flush-limit()

Description: The number of messages that AxoSyslog sends to the Elasticsearch server in a single batch.

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

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

• If flush-limit is higher than 1: AxoSyslog sends messages in a batch, and receives the response asynchronously. In case of a problem, AxoSyslog 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 AxoSyslog recognizes the error. In node mode, about 1000 messages can be lost.

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

frac-digits()

Description: The AxoSyslog 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.

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 hook-commands() when AxoSyslog starts or stops

To execute an external program when AxoSyslog starts or stops, use the following options:

startup()

Description: Defines the external program that is executed as AxoSyslog starts.

shutdown()

Description: Defines the external program that is executed as AxoSyslog stops.

Using the hook-commands() when AxoSyslog reloads

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

setup()

Description: Defines an external program that is executed when the AxoSyslog configuration is initiated, for example, on startup or during a AxoSyslog reload.

teardown()

Description: Defines an external program that is executed when the AxoSyslog configuration is stopped or torn down, for example, on shutdown or during a AxoSyslog reload.

Example: Using the hook-commands() with a network source

In the following example, the hook-commands() is used with the network() driver and it opens an iptables port automatically as AxoSyslog is started/stopped.

The assumption in this example is that the LOGCHAIN chain is part of a larger ruleset that routes traffic to it. Whenever the AxoSyslog created rule is there, packets can flow, otherwise the port is closed.

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

http-auth-type()

Description: Determines how AxoSyslog authenticates to the Elasticsearch server. Depending on the value of this option, you might have to set other options as well. Possible values:

• none: Connect to the Elasticsearch server without authentication.

• basic: Use password authentication. Also set the http-auth-type-basic-username and http-auth-type-basic-password options.

• clientcert: Use a certificate to authenticate. The certificate must be available in a Java keystore. Also set the java-keystore-filepath and java-keystore-password options.

This option is used only in HTTPS mode: client-mode("https"), and is available in AxoSyslog version 3.10 and newer.

Example: HTTPS authentication examples

The following simple examples show the different authentication modes.

Simple password authentication:

   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("basic")
            http-auth-type-basic-username("example-username")
            http-auth-type-basic-password("example-password")
        );
    };

Certificate authentication:

   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")
        );
    };

Verify the certificate of the Elasticsearch server without authentication:

   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("none")
            java-truststore-filepath("<path-to-your-java-keystore>.jks")
            java-truststore-password("password-to-your-keystore")
        );
    };

Verify the certificate of the Elasticsearch server and perform certificate authentication (this is actually a mutual, certificate-based authentication between the AxoSyslog client and the Elasticsearch server):

   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")
        );
    };

http-auth-type-basic-password()

Description: The password to use for password-authentication on the Elasticsearch server. You must also set the http-auth-type-basic-username option.

This option is used only in HTTPS mode with basic authentication: client-mode("https") and http-auth-type("basic"), and is available in AxoSyslog version 3.10 and newer.

Simple password authentication:

   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("basic")
            http-auth-type-basic-username("example-username")
            http-auth-type-basic-password("example-password")
        );
    };

http-auth-type-basic-username()

Description: The username to use for password-authentication on the Elasticsearch server. You must also set the http-auth-type-basic-password option.

This option is used only in HTTPS mode with basic authentication: client-mode("https") and http-auth-type("basic"), and is available in AxoSyslog version 3.10 and newer.

Simple password authentication:

   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("basic")
            http-auth-type-basic-username("example-username")
            http-auth-type-basic-password("example-password")
        );
    };

index()

Description: Name of the Elasticsearch index to store the log messages. You can use macros and templates as well.

java-keystore-filepath()

Description: Path to the Java keystore file that stores the certificate that AxoSyslog uses to authenticate on the Elasticsearch server. You must also set the java-keystore-password option.

To import a certificate into a Java keystore, use the appropriate tool of your Java implementation. For example, on Oracle Java, you can use the keytool utility:

   keytool -import -alias ca -file <certificate-to-import> -keystore <keystore-to-import> -storepass <password-to-the-keystore>

This option is used only in HTTPS mode with basic authentication: client-mode("https") and http-auth-type("clientcert"), and is available in AxoSyslog version 3.10 and newer.

Certificate authentication:

   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")
        );
    };

Verify the certificate of the Elasticsearch server and perform certificate authentication (this is actually a mutual, certificate-based authentication between the AxoSyslog client and the Elasticsearch server):

   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")
        );
    };

java-keystore-password()

Description: The password of the Java keystore file set in the java-keystore-filepath option.

To import a certificate into a Java keystore, use the appropriate tool of your Java implementation. For example, on Oracle Java, you can use the keytool utility:

   keytool -import -alias ca -file <certificate-to-import> -keystore <keystore-to-import> -storepass <password-to-the-keystore>

This option is used only in HTTPS mode with basic authentication: client-mode("https") and http-auth-type("clientcert"), and is available in AxoSyslog version 3.10 and newer.

Certificate authentication:

   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")
        );
    };

Verify the certificate of the Elasticsearch server and perform certificate authentication (this is actually a mutual, certificate-based authentication between the AxoSyslog client and the Elasticsearch server):

   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")
        );
    };

java-truststore-filepath()

Description: Path to the Java keystore file that stores the CA certificate that AxoSyslog uses to verify the certificate of the Elasticsearch server. You must also set the java-truststore-password option.

If you do not set the java-truststore-filepath option, AxoSyslog does accepts any certificate that the Elasticsearch server shows. In this case, the identity of the server is not verified, only the connection is encrypted.

To import a certificate into a Java keystore, use the appropriate tool of your Java implementation. For example, on Oracle Java, you can use the keytool utility:

   keytool -import -alias ca -file <certificate-to-import> -keystore <keystore-to-import> -storepass <password-to-the-keystore>

This option is used only in HTTPS mode: client-mode("https"), and is available in AxoSyslog version 3.10 and newer.

Verify the certificate of the Elasticsearch server without authentication:

   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("none")
            java-truststore-filepath("<path-to-your-java-keystore>.jks")
            java-truststore-password("password-to-your-keystore")
        );
    };

Verify the certificate of the Elasticsearch server and perform certificate authentication (this is actually a mutual, certificate-based authentication between the AxoSyslog client and the Elasticsearch server):

   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")
        );
    };

java-truststore-password()

Description: The password of the Java truststore file set in the java-truststore-filepath option.

To import a certificate into a Java keystore, use the appropriate tool of your Java implementation. For example, on Oracle Java, you can use the keytool utility:

   keytool -import -alias ca -file <certificate-to-import> -keystore <keystore-to-import> -storepass <password-to-the-keystore>

This option is used only in HTTPS mode: client-mode("https"), and is available in AxoSyslog version 3.10 and newer.

Verify the certificate of the Elasticsearch server without authentication:

   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("none")
            java-truststore-filepath("<path-to-your-java-keystore>.jks")
            java-truststore-password("password-to-your-keystore")
        );
    };

Verify the certificate of the Elasticsearch server and perform certificate authentication (this is actually a mutual, certificate-based authentication between the AxoSyslog client and the Elasticsearch server):

   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")
        );
    };

jvm-options()

Description: Specify the Java Virtual Machine (JVM) settings of your Java destination from the AxoSyslog 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.conf configuration file.

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 AxoSyslog cannot convert some data to the specified type. By default, AxoSyslog 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 AxoSyslog.
• 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.

port()

Description: The port number of the Elasticsearch server. This option is used only in transport mode: client-mode("transport")

retries()

Description: If AxoSyslog cannot send a message, it will try again until the number of attempts reaches retries().

If the number of attempts reaches retries(), AxoSyslog will wait for time-reopen() time, then tries sending the message again.

resource()

Description: The list of Elasticsearch resources to load, separated by semicolons. For example, resource("/home/user/elasticsearch/elasticsearch.yml;/home/user/elasticsearch/elasticsearch2.yml").

server()

Description: Specifies the hostname or IP address of the Elasticsearch server. When specifying an IP address, IPv4 (for example, 192.168.0.1) or IPv6 (for example, [::1]) can be used as well. When specifying multiple addresses, use space to separate the addresses, for example, server("127.0.0.1 remote-server-hostname1 remote-server-hostname2")

This option is used only in transport mode: client-mode("transport")

In version 3.10 and newer, you can list multiple servers in HTTP and HTTPS mode in the cluster-url() and server() options. The AxoSyslog application will use these destination servers in load-balancing fashion. Note that load-balancing is handled by an external library (Jest), AxoSyslog does not have any direct influence on it.

For example:

   destination d_elasticsearch {
      elasticsearch2(
        client-lib-dir("/usr/share/elasticsearch/lib/")
        index("syslog-${YEAR}.${MONTH}.${DAY}")
        type("syslog")
        time-zone("UTC")
        client-mode("http")
        server("node01 node02")
        port(9200)
      );
    };

skip-cluster-health-check()

Description: By default, when connecting to an Elasticsearch cluster, AxoSyslog checks the state of the cluster. If the primary shards of the cluster are not active, AxoSyslog will not send messages, but wait for them to become active. To disable this health check and send the messages to Elasticsearch anyway, use the skip-cluster-health-check(yes) option in your configuration.

template()

Description: The message as sent to the Elasticsearch server. Typically, you will want to use the command-line notation of the format-json template function.

To add a @timestamp field to the message, for example, to use with Kibana, include the @timestamp=${ISODATE} expression in the template. For example: template($(format-json --scope rfc5424 --exclude DATE --key ISODATE @timestamp=${ISODATE}))

For details on formatting messages in JSON format, see format-json.

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.

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 by using the name, 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.

Version 3.10 and newer of AxoSyslog automatically converts the timestamp (date) of the message to UTC, as needed by Elasticsearch and Kibana.

ts-format()

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

type()

Description: The type of the index. For example, type("test").