Working with Logstash Modules

Logstash modules provide a quick, end-to-end solution for ingesting data and visualizing it with purpose-built dashboards.

Each module comes pre-packaged with Logstash configurations, Kibana dashboards, and other meta files that make it easier for you to set up the Elastic Stack for specific use cases or data sources.

You can think of modules as providing three essential functions that make it easier for you to get started. When you run a module, it will:

To run a module and set up dashboards, you specify the following options:

bin/logstash --modules MODULE_NAME --setup [-M "CONFIG_SETTING=VALUE"]

Where:

For example, the following command runs the Netflow module with the default settings, and sets up the netflow index pattern and dashboards:

bin/logstash --modules netflow --setup

The following command runs the Netflow module and overrides the Elasticsearch host setting. Here it’s assumed that you’ve already run the setup step.

bin/logstash --modules netflow -M "netflow.var.elasticsearch.host=es.mycloud.com"

To configure a module, you can either specify configuration settings in the logstash.yml settings file, or use command-line overrides to specify settings at the command line.

To specify module settings in the logstash.yml settings file file, you add a module definition to the modules array. Each module definition begins with a dash (-) and is followed by name: module_name then a series of name/value pairs that specify module settings. For example:

modules:
- name: netflow
  var.elasticsearch.hosts: "es.mycloud.com"
  var.elasticsearch.username: "foo"
  var.elasticsearch.password: "password"
  var.kibana.host: "kb.mycloud.com"
  var.kibana.username: "foo"
  var.kibana.password: "password"
  var.input.tcp.port: 5606

For a list of available module settings, see the documentation for the module.

You can override module settings by specifying one or more configuration overrides when you start Logstash. To specify an override, you use the -M command line option:

-M MODULE_NAME.var.PLUGINTYPE1.PLUGINNAME1.KEY1=VALUE

Notice that the fully-qualified setting name includes the module name.

You can specify multiple overrides. Each override must start with -M.

The following command runs the Netflow module and overrides both the Elasticsearch host setting and the udp.port setting:

bin/logstash --modules netflow -M "netflow.var.input.udp.port=3555" -M "netflow.var.elasticseach.host=my-es-cloud"

Any settings defined in the command line are ephemeral and will not persist across subsequent runs of Logstash. If you want to persist a configuration, you need to set it in the logstash.yml settings file.

Settings that you specify at the command line are merged with any settings specified in the logstash.yml file. If an option is set in both places, the value specified at the command line takes precedence.