elasticsearch2: Sending messages directly to Elasticsearch version 2.0 or higher (DEPRECATED)
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Caution:
This destination is deprecated and will be removed from a future version of syslog-ng OSE. We recommend using the elasticsearch-http: Sending messages to Elasticsearch HTTP Bulk API destination instead. |
Starting with version
Note the following limitations when using the syslog-ng OSE elasticsearch2 destination:
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This destination is only supported on the Linux platform.
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Since syslog-ng OSE uses Java libraries, the elasticsearch2 destination has significant memory usage.
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The log messages of the underlying client libraries are available in the internal() source of syslog-ng OSE.
Declaration:
@include "scl.conf"
elasticsearch2(
index("syslog-ng_${YEAR}.${MONTH}.${DAY}")
type("test")
cluster("syslog-ng")
);Example: Sending log data to Elasticsearch version 2.x and above
The following example defines an elasticsearch2 destination that sends messages in transport mode to an Elasticsearch server running on the localhost, using only the required parameters.
@include "scl.conf"
destination d_elastic {
elasticsearch2(
index("syslog-ng_${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.
@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);
};Example: Sending log data to Elasticsearch using the HTTP REST API
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);
};
Verify the certificate of the Elasticsearch server and perform certificate authentication (this is actually a mutual, certificate-based authentication between the syslog-ng OSE 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")
);
};-
To install the software required for the elasticsearch2 destination, see Prerequisites.
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For details on how the elasticsearch2 destination works, see How syslog-ng OSE interacts with Elasticsearch.
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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.
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
To send messages from syslog-ng OSE to Elasticsearch, complete the following steps.
Steps:
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Download and install the Java Runtime Environment (JRE), 2.x (or newer). The syslog-ng OSEelasticsearch2 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.
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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.
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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 OSE can access them. You must specify this directory in the syslog-ng OSE configuration file. The files are located in the lib directory and its subdirectories of the Elasticsearch release package.
How syslog-ng OSE interacts with Elasticsearch
The syslog-ng OSE application sends the log messages to the official Elasticsearch client library, which forwards the data to the Elasticsearch nodes. The way syslog-ng OSE interacts with Elasticsearch is described in the following steps.
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After syslog-ng OSE 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 OSE will repeatedly attempt to connect again after the period set in time-reopen() expires.
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If the connection is established, syslog-ng OSE sends JSON-formatted messages to Elasticsearch.
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If flush-limit is set to 1: syslog-ng OSE sends the message reliably: it sends a message to Elasticsearch, then waits for a reply from Elasticsearch. In case of failure, syslog-ng OSE repeats sending the message, as set in the retries() parameter. If sending the message fails for retries() times, syslog-ng OSE drops the message.
This method ensures reliable message transfer, but is slow (about 1000 messages/second).
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If flush-limit is higher than 1: syslog-ng OSE sends messages in a batch, and receives the response asynchronously. In case of a problem, syslog-ng OSE 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 OSE recognizes the error. In node mode, about 1000 messages can be lost.
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If concurrent-requests is higher than 1, syslog-ng OSE can send multiple batches simultaneously, increasing performance (and also the number of messages that can be lost in case of an error).
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Version
Client modes
The syslog-ng OSE application can interact with Elasticsearch in the following modes of operation:
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HTTP mode
The syslog-ng OSE application sends messages over HTTP using the REST API of Elasticsearch, and uses the cluster-url() and cluster() options from the syslog-ng OSE configuration file. In HTTP mode, syslog-ng OSEelasticsearch2 driver can send log messages to every Elasticsearch version, including 1.x-6.x. Note that HTTP mode is available in syslog-ng OSE version
In version
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HTTPS mode
The syslog-ng OSE 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 syslog-ng OSE configuration file. In HTTPS mode, syslog-ng OSEelasticsearch2 driver can send log messages to every Elasticsearch version, including 1.x-6.x. Note that HTTPS mode is available in syslog-ng OSE version
This mode supports password-based and certificate-based authentication of the client, and can verify the certificate of the server as well.
In version
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Transport mode
The syslog-ng OSE application uses the transport client API of Elasticsearch, and uses the server(), port(), and cluster() options from the syslog-ng OSE configuration file.
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Node mode
The syslog-ng OSE 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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Search Guard mode
Use the Search Guard Elasticsearch plugin to encrypt and authenticate your connections from syslog-ng OSE to Elasticsearch 2.x. For Elasticsearch versions 5.x and newer, use HTTPS mode. For details on configuring Search Guard mode, see Search Guard and syslog-ng OSE.