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logstash.yml

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logstash.yml

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You can set options in the Logstash settings file, logstash.yml, to control Logstash execution. For example, you can specify pipeline settings, the location of configuration files, logging options, and other settings. Most of the settings in the logstash.yml file are also available as command-line flags when you run Logstash. Any flags that you set at the command line override the corresponding settings in the logstash.yml file.

The logstash.yml file is written in YAML. Its location varies by platform (see Logstash Directory Layout). You can specify settings in hierarchical form or use flat keys. For example, to use hierarchical form to set the pipeline batch size and batch delay, you specify:

pipeline:
  batch:
    size: 125
    delay: 5

To express the same values as flat keys, you specify:

pipeline.batch.size: 125
pipeline.batch.delay: 5

The logstash.yml file also supports bash-style interpolation of environment variables in setting values.

pipeline:
  batch:
    size: ${BATCH_SIZE}
    delay: ${BATCH_DELAY:5}
node:
  name: "node_${LS_NODE_NAME}"
path:
   queue: "/tmp/${QUEUE_DIR:queue}"

Note that the ${VAR_NAME:default_value} notation is supported, setting a default batch delay of 5 and a default path.queue of /tmp/queue in the above example.

Modules may also be specified in the logstash.yml file. The modules definition will have this format:

modules:
  - name: MODULE_NAME1
    var.PLUGIN_TYPE1.PLUGIN_NAME1.KEY1: VALUE
    var.PLUGIN_TYPE1.PLUGIN_NAME1.KEY2: VALUE
    var.PLUGIN_TYPE2.PLUGIN_NAME2.KEY1: VALUE
    var.PLUGIN_TYPE3.PLUGIN_NAME3.KEY1: VALUE
  - name: MODULE_NAME2
    var.PLUGIN_TYPE1.PLUGIN_NAME1.KEY1: VALUE
    var.PLUGIN_TYPE1.PLUGIN_NAME1.KEY2: VALUE

If the command-line flag --modules is used, any modules defined in the logstash.yml file will be ignored.

The logstash.yml file includes the following settings:

Setting	Description	Default value
`node.name`	A descriptive name for the node.	Machine’s hostname
`path.data`	The directory that Logstash and its plugins use for any persistent needs.	`LOGSTASH_HOME/data`
`pipeline.workers`	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.	Number of the host’s CPU cores
`pipeline.batch.size`	The maximum number of events an individual worker thread will collect from inputs before attempting to execute its filters and outputs. 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.	`125`
`pipeline.batch.delay`	When creating pipeline event batches, how long in milliseconds to wait for each event before dispatching an undersized batch to pipeline workers.	`5`
`pipeline.unsafe_shutdown`	When set to `true`, forces 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.	`false`
`path.config`	The path to the Logstash config for the main pipeline. If you specify a directory or wildcard, config files are read from the directory in alphabetical order.	Platform-specific. See Logstash Directory Layout.
`config.string`	A string that contains the pipeline configuration to use for the main pipeline. Use the same syntax as the config file.	None
`config.test_and_exit`	When set to `true`, checks that the configuration is valid and then exits. Note that grok patterns are not checked for correctness with this setting. Logstash can read multiple config files from a directory. If you combine this setting with `log.level: debug`, Logstash will log the combined config file, annotating each config block with the source file it came from.	`false`
`config.reload.automatic`	When set to `true`, periodically checks if the configuration has changed and reloads the configuration whenever it is changed. This can also be triggered manually through the SIGHUP signal.	`false`
`config.reload.interval`	How often in seconds Logstash checks the config files for changes.	`3s`
`config.debug`	When set to `true`, shows the fully compiled configuration as a debug log message. You must also set `log.level: debug`. 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!	`false`
`config.support_escapes`	When set to `true`, quoted strings will process the following escape sequences: `\n` becomes a literal newline (ASCII 10). `\r` becomes a literal carriage return (ASCII 13). `\t` becomes a literal tab (ASCII 9). `\\` becomes a literal backslash `\`. `\"` becomes a literal double quotation mark. `\'` becomes a literal quotation mark.	`false`
`modules`	When configured, `modules` must be in the nested YAML structure described above this table.	None
`queue.type`	The internal queuing model to use for event buffering. Specify `memory` for legacy in-memory based queuing, or `persisted` for disk-based ACKed queueing (persistent queues).	`memory`
`path.queue`	The directory path where the data files will be stored when persistent queues are enabled (`queue.type: persisted`).	`path.data/queue`
`queue.page_capacity`	The size of the page data files used when persistent queues are enabled (`queue.type: persisted`). The queue data consists of append-only data files separated into pages.	250mb
`queue.max_events`	The maximum number of unread events in the queue when persistent queues are enabled (`queue.type: persisted`).	0 (unlimited)
`queue.max_bytes`	The total capacity of the queue in number of bytes. Make sure the capacity of your disk drive is greater than the value you specify here. If both `queue.max_events` and `queue.max_bytes` are specified, Logstash uses whichever criteria is reached first.	1024mb (1g)
`queue.checkpoint.acks`	The maximum number of ACKed events before forcing a checkpoint when persistent queues are enabled (`queue.type: persisted`). Specify `queue.checkpoint.acks: 0` to set this value to unlimited.	1024
`queue.checkpoint.writes`	The maximum number of written events before forcing a checkpoint when persistent queues are enabled (`queue.type: persisted`). Specify `queue.checkpoint.writes: 0` to set this value to unlimited.	1024
`queue.drain`	When enabled, Logstash waits until the persistent queue is drained before shutting down.	false
`dead_letter_queue.enable`	Flag to instruct Logstash to enable the DLQ feature supported by plugins.	`false`
`dead_letter_queue.max_bytes`	The maximum size of each dead letter queue. Entries will be dropped if they would increase the size of the dead letter queue beyond this setting.	`1024mb`
`path.dead_letter_queue`	The directory path where the data files will be stored for the dead-letter queue.	`path.data/dead_letter_queue`
`http.host`	The bind address for the metrics REST endpoint.	`"127.0.0.1"`
`http.port`	The bind port for the metrics REST endpoint.	`9600`
`log.level`	The log level. Valid options are: `fatal` `error` `warn` `info` `debug` `trace`	`info`
`log.format`	The log format. Set to `json` to log in JSON format, or `plain` to use `Object#.inspect`.	`plain`
`path.logs`	The directory where Logstash will write its log to.	`LOGSTASH_HOME/logs`
`path.plugins`	Where to find custom plugins. You can specify this setting 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.	Platform-specific. See Logstash Directory Layout.

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