logstash.yml

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: 50

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

pipeline.batch.size: 125
pipeline.batch.delay: 50

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

pipeline:
  batch:
    size: ${BATCH_SIZE}
    delay: ${BATCH_DELAY:50}
node:
  name: "node_${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 50 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.id`	The ID of the pipeline.	`main`
`pipeline.java_execution`	Use the Java execution engine.	true
`pipeline.workers`	The number of workers that will, in parallel, execute the filter and output stages of the pipeline. This setting uses the `java.lang.Runtime.getRuntime.availableProcessors` value as a default if not overridden by `pipeline.workers` in `pipelines.yml` or `pipeline.workers` from `logstash.yml`. If you have modified this setting and see 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.	`50`
`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`
`pipeline.plugin_classloaders`	(Beta) Load Java plugins in independent classloaders to isolate their dependencies.	`false`
`pipeline.ordered`	Set the pipeline event ordering.Valid options are: `auto` `true` `false` `auto` will automatically enable ordering if the `pipeline.workers` setting is also set to `1`. `true` will enforce ordering on the pipeline and prevent logstash from starting if there are multiple workers. `false` will disable the processing required to preserve order. Ordering will not be guaranteed, but you save the processing cost of preserving order.	`auto`
`pipeline.ecs_compatibility`	Sets the pipeline’s default value for `ecs_compatibility`, a setting that is available to plugins that implement an ECS compatibility mode for use with the Elastic Common Schema. Possible values are: `disabled` `v1` `v8` This option allows the early opt-in (or preemptive opt-out) of ECS compatibility modes in plugins, which is scheduled to be on-by-default in a future major release of Logstash. Values other than `disabled` are currently considered BETA, and may produce unintended consequences when upgrading Logstash.	`disabled`
`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. Note that the unit qualifier (`s`) is required.	`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.	64mb
`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 (`queue.type: persisted`) 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.checkpoint.retry`	When enabled, Logstash will retry four times per attempted checkpoint write for any checkpoint writes that fail. Any subsequent errors are not retried. This is a workaround for failed checkpoint writes that have been seen only on Windows platform, filesystems with non-standard behavior such as SANs and is not recommended except in those specific circumstances. (`queue.type: persisted`)	`true`
`queue.drain`	When enabled, Logstash waits until the persistent queue (`queue.type: persisted`) 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`
`api.enabled`	The HTTP API is enabled by default. It can be disabled, but features that rely on it will not work as intended.	`true`
`api.environment`	The API returns the provided string as a part of its response. Setting your environment may help to disambiguate between similarly-named nodes in production vs test environments.	`production`
`api.http.host`	The bind address for the HTTP API endpoint. By default, the Logstash HTTP API binds only to the local loopback interface. When configured securely (`api.ssl.enabled: true` and `api.auth.type: basic`), the HTTP API binds to all available interfaces.	`"127.0.0.1"`
`api.http.port`	The bind port for the HTTP API endpoint.	`9600-9700`
`api.ssl.enabled`	Set to `true` to enable SSL on the HTTP API. Doing so requires both `api.ssl.keystore.path` and `api.ssl.keystore.password` to be set.	`false`
`api.ssl.keystore.path`	The path to a valid JKS or PKCS12 keystore for use in securing the Logstash API. The keystore must be password-protected, and must contain a single certificate chain and a private key. This setting is ignored unless `api.ssl.enabled` is set to `true`.	N/A
`api.ssl.keystore.password`	The password to the keystore provided with `api.ssl.keystore.path`. This setting is ignored unless `api.ssl.enabled` is set to `true`.	N/A
`api.auth.type`	Set to `basic` to require HTTP Basic auth on the API using the credentials supplied with `api.auth.basic.username` and `api.auth.basic.password`.	`none`
`api.auth.basic.username`	The username to require for HTTP Basic auth Ignored unless `api.auth.type` is set to `basic`.	N/A
`api.auth.basic.password`	The password to require for HTTP Basic auth Ignored unless `api.auth.type` is set to `basic`.	N/A
`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`
`pipeline.separate_logs`	This a boolean setting to enable separation of logs per pipeline in different log files. If enabled Logstash will create a different log file for each pipeline, using the pipeline.id as name of the file. The destination directory is taken from the `path.log`s setting. When there are many pipelines configured in Logstash, separating each log lines per pipeline could be helpful in case you need to troubleshoot what’s happening in a single pipeline, without interference of the other ones.	`false`
`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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