The logging section of the metricbeat.yml config file contains options for configuring the Beats logging output. The logging system can write logs to syslog or rotate log files. If logging is not explicitly configured, file output is used on Windows systems, and syslog output is used on Linux and OS X.

logging.level: warning
logging.to_files: true
logging.to_syslog: false
  path: /var/log/mybeat
  name: mybeat.log
  keepfiles: 7

In addition to the logging system, the logging output configuration can be modified from the command line.

Logging Optionsedit

You can specify the following options in the logging section of the metricbeat.yml config file:


If enabled, sends all logging output to syslog. The default value is false.


Writes all logging output to files subject to file rotation. The default value is true.


Minimum log level. One of debug, info, warning, error or critical. If debug is used, but no selectors are configured, the * selector will be used. The default log level is "info".


The list of debugging-only selector tags used by different Beats components. Use * to enable debug output for all components. For example add publish to display all the debug messages related to event publishing. When starting the Beat, selectors can be overwritten using the -d command line option (-d also sets the debug log level).


If enabled, Metricbeat periodically logs its internal metrics that have changed in the last period. For each metric that changed, the delta from the value at the beginning of the period is logged. Also, the total values for all non-zero internal metrics are logged on shutdown. The default is true.

Here is an example log line:

2016/07/04 12:16:10.821047 logp.go:194: INFO Non-zero metrics in the last 30s:  libbeatEsPublishedAndAckedEvents=18 libbeatEsPublishWriteBytes=10045

Note that we currently offer no backwards compatible guarantees for the internal metrics and for this reason they are also not documented.


The period after which to log the internal metrics. The default is 30s.


The directory that log files are written to. The default is the logs path. See the Directory Layout section for details.


The name of the file that logs are written to. By default, the name of the Beat is used.


The maximum size of a log file. If the limit is reached, a new log file is generated. The default size limit is 10485760 (10 MB).


The number of most recent rotated log files to keep on disk. Older files are deleted during log rotation. The default value is 7. The keepfiles options has to be in the range of 2 to 1024 files.

Logging Formatedit

The logging format is different for each logging type:

  • to syslog: Syslog adds the timestamp itself.
  • to file: RFC 3339 format is used for the timestamp: 2006-01-02T15:04:05Z07:00 WARN log-message. The format includes the timezone followed by the logging level.
  • to stderr: UTC format is used for the timestamp: 2015/11/12 09:03:37.369262 geolite.go:52: WARN log-message. The format includes the UTC timestamp with the milliseconds, then the name of the caller that sent the log entry followed by the logging level. This option should be used mainly for debugging.