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Elastic Docs ›Logstash Reference [6.8] ›Setting Up and Running Logstash

Running Logstash from the Command Line

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Running Logstash from the Command Line

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To run Logstash from the command line, use the following command:

bin/logstash [options]

To run Logstash from the Windows command line, use the following command:

bin/logstash.bat [options]

Where options are command-line flags that you can specify to control Logstash execution. The location of the bin directory varies by platform. See Logstash Directory Layout to find the location of bin\logstash on your system.

The following example runs Logstash and loads the Logstash config defined in the mypipeline.conf file:

bin/logstash -f mypipeline.conf

Any flags that you set at the command line override the corresponding settings in logstash.yml, but the file itself is not changed. It remains as-is for subsequent Logstash runs.

Specifying command line options is useful when you are testing Logstash. However, in a production environment, we recommend that you use logstash.yml to control Logstash execution. Using the settings file makes it easier for you to specify multiple options, and it provides you with a single, versionable file that you can use to start up Logstash consistently for each run.

Command-Line Flags

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Logstash has the following flags. You can use the --help flag to display this information.

--node.name NAME
Specify the name of this Logstash instance. If no value is given it will default to the current hostname.
-f, --path.config CONFIG_PATH

Load the Logstash config from a specific file or directory. If a directory is given, all files in that directory will be concatenated in lexicographical order and then parsed as a single config file. Specifying this flag multiple times is not supported. If you specify this flag multiple times, Logstash uses the last occurrence (for example, -f foo -f bar is the same as -f bar).

You can specify wildcards (globs) and any matched files will be loaded in the order described above. For example, you can use the wildcard feature to load specific files by name:

bin/logstash --debug -f '/tmp/{one,two,three}'

With this command, Logstash concatenates three config files, /tmp/one, /tmp/two, and /tmp/three, and parses them into a single config.

-e, --config.string CONFIG_STRING
Use the given string as the configuration data. Same syntax as the config file. If no input is specified, then the following is used as the default input: input { stdin { type => stdin } } and if no output is specified, then the following is used as the default output: output { stdout { codec => rubydebug } }. If you wish to use both defaults, please use the empty string for the -e flag. The default is nil.
--java-execution
Use the Java execution engine instead of the default Ruby execution engine.
--modules
Launch the named module. Works in conjunction with the -M option to assign values to default variables for the specified module. If --modules is used on the command line, any modules in logstash.yml will be ignored, as will any settings there. This flag is mutually exclusive to the -f and -e flags. Only one of -f, -e, or --modules may be specified. Multiple modules can be specified by separating them with a comma, or by invoking the --modules flag multiple times.
-M, --modules.variable
Assign a value to a configurable option for a module. The format for assigning variables is -M "MODULE_NAME.var.PLUGIN_TYPE.PLUGIN_NAME.KEY_NAME=value" for Logstash variables. For other settings, it will be -M "MODULE_NAME.KEY_NAME.SUB_KEYNAME=value". The -M flag can be used as many times as is necessary. If no -M options are specified, then the default value for that setting will be used. The -M flag is only used in conjunction with the --modules flag. It will be ignored if the --modules flag is absent.
--pipeline.id ID
Sets the ID of pipeline. The default is main.
-w, --pipeline.workers COUNT
Sets the number of pipeline workers to run. This option sets the number of workers that will, in parallel, execute the filter and output stages of the pipeline. If you find that events are backing up, or that the CPU is not saturated, consider increasing this number to better utilize machine processing power. The default is the number of the host’s CPU cores.
-b, --pipeline.batch.size SIZE
Size of batches the pipeline is to work in. This option defines the maximum number of events an individual worker thread will collect from inputs before attempting to execute its filters and outputs. The default is 125 events. Larger batch sizes are generally more efficient, but come at the cost of increased memory overhead. You may need to increase JVM heap space in the jvm.options config file. See Logstash Configuration Files for more info.
-u, --pipeline.batch.delay DELAY_IN_MS
When creating pipeline batches, how long to wait while polling for the next event. This option defines how long in milliseconds to wait while polling for the next event before dispatching an undersized batch to filters and outputs. The default is 50ms.
--pipeline.unsafe_shutdown
Force Logstash to exit during shutdown even if there are still inflight events in memory. By default, Logstash will refuse to quit until all received events have been pushed to the outputs. Enabling this option can lead to data loss during shutdown.
--path.data PATH
This should point to a writable directory. Logstash will use this directory whenever it needs to store data. Plugins will also have access to this path. The default is the data directory under Logstash home.
-p, --path.plugins PATH
A path of where to find custom plugins. This flag can be given multiple times to include multiple paths. Plugins are expected to be in a specific directory hierarchy: PATH/logstash/TYPE/NAME.rb where TYPE is inputs, filters, outputs, or codecs, and NAME is the name of the plugin.
-l, --path.logs PATH
Directory to write Logstash internal logs to.
--log.level LEVEL

Set the log level for Logstash. Possible values are:

  • fatal: log very severe error messages that will usually be followed by the application aborting
  • error: log errors
  • warn: log warnings
  • info: log verbose info (this is the default)
  • debug: log debugging info (for developers)
  • trace: log finer-grained messages beyond debugging info
--config.debug
Show the fully compiled configuration as a debug log message (you must also have --log.level=debug enabled). WARNING: The log message will include any password options passed to plugin configs as plaintext, and may result in plaintext passwords appearing in your logs!
-i, --interactive SHELL
Drop to shell instead of running as normal. Valid shells are "irb" and "pry".
-V, --version
Emit the version of Logstash and its friends, then exit.
-t, --config.test_and_exit
Check configuration for valid syntax and then exit. Note that grok patterns are not checked for correctness with this flag. Logstash can read multiple config files from a directory. If you combine this flag with --log.level=debug, Logstash will log the combined config file, annotating each config block with the source file it came from.
-r, --config.reload.automatic
Monitor configuration changes and reload whenever the configuration is changed. NOTE: Use SIGHUP to manually reload the config. The default is false.
--config.reload.interval RELOAD_INTERVAL
How frequently to poll the configuration location for changes. The default value is "3s". Note that the unit qualifier (s) is required.
--http.host HTTP_HOST
Web API binding host. This option specifies the bind address for the metrics REST endpoint. The default is "127.0.0.1".
--http.port HTTP_PORT
Web API http port. This option specifies the bind port for the metrics REST endpoint. The default is 9600-9700. This setting accepts a range of the format 9600-9700. Logstash will pick up the first available port.
--log.format FORMAT
Specify if Logstash should write its own logs in JSON form (one event per line) or in plain text (using Ruby’s Object#inspect). The default is "plain".
--path.settings SETTINGS_DIR
Set the directory containing the logstash.yml settings file as well as the log4j logging configuration. This can also be set through the LS_SETTINGS_DIR environment variable. The default is the config directory under Logstash home.
-h, --help
Print help
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