Getting Started with Logstash

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Getting Started with Logstash

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This section guides you through the process of installing Logstash and verifying that everything is running properly. After learning how to stash your first event, you go on to create a more advanced pipeline that takes Apache web logs as input, parses the logs, and writes the parsed data to an Elasticsearch cluster. Then you learn how to stitch together multiple input and output plugins to unify data from a variety of disparate sources.

This section includes the following topics:

Java (JVM) version

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Logstash requires one of these versions:

  • Java 17 (default). Check out Using JDK 17 for settings info.
  • Java 21

Use the official Oracle distribution or an open-source distribution, such as OpenJDK. See the Elastic Support Matrix for the official word on supported versions across releases.

Bundled JDK

Logstash offers architecture-specific downloads that include Adoptium Eclipse Temurin 17, a long term support (LTS) release of the JDK.

Use the LS_JAVA_HOME environment variable if you want to use a JDK other than the version that is bundled. If you have the LS_JAVA_HOME environment variable set to use a custom JDK, Logstash will continue to use the JDK version you have specified, even after you upgrade.

Check your Java version

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Run the following command:

java -version

On systems with Java installed, this command produces output similar to the following:

openjdk version "17.0.12" 2024-07-16
OpenJDK Runtime Environment Temurin-17.0.12+7 (build 17.0.12+7)
OpenJDK 64-Bit Server VM Temurin-17.0.12+7 (build 17.0.12+7, mixed mode)

LS_JAVA_HOME

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Logstash includes a bundled JDK which has been verified to work with each specific version of Logstash, and generally provides the best performance and reliability. If you need to use a JDK other than the bundled version, then set the LS_JAVA_HOME environment variable to the version you want to use.

On some Linux systems, you may need to have the LS_JAVA_HOME environment exported before installing Logstash, particularly if you installed Java from a tarball. Logstash uses Java during installation to automatically detect your environment and install the correct startup method (SysV init scripts, Upstart, or systemd). If Logstash is unable to find the LS_JAVA_HOME environment variable during package installation, you may get an error message, and Logstash will not start properly.

Using JDK 17

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Logstash uses JDK 17 by default, but you need to update settings in jvm.options and log4j2.properties if you are upgrading from Logstash 7.11.x (or earlier) to 7.12 or later.

Updates to jvm.options
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In the config/jvm.options file, remove all CMS related flags:

## GC configuration
-XX:+UseConcMarkSweepGC
-XX:CMSInitiatingOccupancyFraction=75
-XX:+UseCMSInitiatingOccupancyOnly

For more information about how to use jvm.options, please refer to JVM settings.

Updates to log4j2.properties
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In the config/log4j2.properties:

  • Replace properties that start with appender.rolling.avoid_pipelined_filter.* with:

    appender.rolling.avoid_pipelined_filter.type = PipelineRoutingFilter
  • Replace properties that start with appender.json_rolling.avoid_pipelined_filter.* with:

    appender.json_rolling.avoid_pipelined_filter.type = PipelineRoutingFilter
  • Replace properties that start with appender.routing.* with:

    appender.routing.type = PipelineRouting
    appender.routing.name = pipeline_routing_appender
    appender.routing.pipeline.type = RollingFile
    appender.routing.pipeline.name = appender-${ctx:pipeline.id}
    appender.routing.pipeline.fileName = ${sys:ls.logs}/pipeline_${ctx:pipeline.id}.log
    appender.routing.pipeline.filePattern = ${sys:ls.logs}/pipeline_${ctx:pipeline.id}.%i.log.gz
    appender.routing.pipeline.layout.type = PatternLayout
    appender.routing.pipeline.layout.pattern = [%d{ISO8601}][%-5p][%-25c] %m%n
    appender.routing.pipeline.policy.type = SizeBasedTriggeringPolicy
    appender.routing.pipeline.policy.size = 100MB
    appender.routing.pipeline.strategy.type = DefaultRolloverStrategy
    appender.routing.pipeline.strategy.max = 30