Logging settings in Kibana

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Logging settings in Kibana

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You do not need to configure any additional settings to use the logging features in Kibana. Logging is enabled by default and will log at info level using the pattern layout, which outputs logs to stdout.

However, if you are planning to ingest your logs using Elasticsearch or another tool, we recommend using the json layout, which produces logs in ECS format. In general, pattern layout is recommended when raw logs will be read by a human, and json layout when logs will be read by a machine.

The logging configuration is validated against the predefined schema and if there are any issues with it, Kibana will fail to start with the detailed error message.

Kibana relies on three high-level entities to set the logging service: appenders, loggers, and root. These can be configured in the logging namespace in kibana.yml.

  • Appenders define where log messages are displayed (stdout or console) and their layout (pattern or json). They also allow you to specify if you want the logs stored and, if so, where (file on the disk).
  • Loggers define what logging settings, such as the level of verbosity and the appenders, to apply to a particular context. Each log entry context provides information about the service or plugin that emits it and any of its sub-parts, for example, metrics.ops or elasticsearch.query.
  • Root is a logger that applies to all the log entries in Kibana.

The following table serves as a quick reference for different logging configuration keys. Note that these are not stand-alone settings and may require additional logging configuration. See the Configure Logging in Kibana guide and complete examples for common configuration use cases.

logging.appenders[].<appender-name>

Unique appender identifier.

logging.appenders[].console:

Appender to use for logging records to stdout. By default, uses the [%date][%level][%logger] %message pattern layout. To use a json, set the layout type to json.

logging.appenders[].file:

Allows you to specify a fileName to write log records to disk. To write all log records to file, add the file appender to root.appenders. If configured, you also need to specify logging.appenders.file.pathName.

logging.appenders[].rolling-file:

Similar to Log4j’s RollingFileAppender, this appender will log to a file and rotate if following a rolling strategy when the configured policy triggers. There are currently two policies supported: size-limit and time-interval.

logging.appenders[].<appender-name>.type

The appender type determines where the log messages are sent. Options are console, file, rewrite, rolling-file. Required.

logging.appenders[].<appender-name>.fileName

Determines the filepath where the log messages are written to for file and rolling-file appender types. Required for appenders that write to file.

logging.appenders[].<appender-name>.policy.type

Specify the triggering policy for when a rollover should occur for the rolling-file type appender.

logging.appenders[].<appender-name>.policy.interval

Specify the time interval for rotating a log file for a time-interval type rolling-file appender. Default 24h

logging.appenders[].<appender-name>.policy.size

Specify the size limit at which the policy should trigger a rollover for a size-limit type rolling-file appender. Default 100mb.

logging.appenders[].<appender-name>.policy.interval

Specify the time interval at which the policy should trigger a rollover for a time-interval type rolling-file appender.

logging.appenders[].<appender-name>.policy.modulate

Whether the interval should be adjusted to cause the next rollover to occur on the interval boundary. Boolean. Default true.

logging.appenders[].<appender-name>.strategy.type

Rolling file strategy type. Only numeric is currently supported.

logging.appenders[].<appender-name>.strategy.pattern

The suffix to append to the file path when rolling. Must include %i.

logging.appenders[].<appender-name>.strategy.max

The maximum number of files to keep. Optional. Default is 7 and the maximum is 100.

logging.appenders[].<appender-name>.layout.type

Determines how the log messages are displayed. Options are pattern, which provides human-readable output, or json, which provides ECS-compliant output. Required.

logging.appenders[].<appender-name>.layout.highlight

Optional boolean to highlight log messages in color. Applies to pattern layout only. Default is false.

logging.appenders[].<appender-name>.layout.pattern

Optional string pattern for placeholders that will be replaced with data from the actual log message. Applicable to pattern type layout only.

logging.root.appenders[]

List of specific appenders to apply to root. Defaults to console with pattern layout.

logging.root.level

Specify default verbosity for all log messages to fall back to if not specifically configured at the individual logger level. Options are all, fatal, error, warn, info, debug, trace, off. The all and off levels can be used only in configuration and are just handy shortcuts that allow you to log every log record or disable logging entirely or for a specific logger. Default is info.

logging.loggers[].<logger>.name:

Specific logger instance.

logging.loggers[].<logger>.level

Specify verbosity of log messages for <logger> context. Optional and inherits the verbosity of any ancestor logger, up to the root logger level.

logging.loggers[].<logger>.appenders

Determines the appender to apply to a specific logger context as an array. Optional and falls back to the appender(s) of the root logger if not specified.