Logstash module

The logstash module parse logstash regular logs and the slow log, it will support the plain text format and the JSON format (--log.format json). The default is the plain text format.

When you run the module, it performs a few tasks under the hood:

  • Sets the default paths to the log files (but don’t worry, you can override the defaults)
  • Makes sure each multiline log event gets sent as a single event
  • Uses ingest node to parse and process the log lines, shaping the data into a structure suitable for visualizing in Kibana
  • Deploys dashboards for visualizing the log data

Read the quick start to learn how to set up and run modules.

The logstash module has two filesets:

  • The log fileset collects and parses the logs that Logstash writes to disk.
  • The slowlog fileset parses the logstash slowlog.

For the slowlog fileset, make sure to configure the Logstash slowlog option.

Compatibility

The Logstash log fileset was tested with logs from Logstash 5.6 and 6.0.

The Logstash slowlog fileset was tested with logs from Logstash 5.6 and 6.0

Configure the module

You can further refine the behavior of the logstash module by specifying variable settings in the modules.d/logstash.yml file, or overriding settings at the command line.

The following example shows how to set paths in the modules.d/logstash.yml file to override the default paths for Logstash logs and set the format to json

- module: logstash
  log:
    enabled: true
    var.paths: ["/path/to/log/logstash.log*"]
    var.format: json
  slowlog:
    enabled: true
    var.paths: ["/path/to/log/logstash-slowlog.log*"]
    var.format: json

To specify the same settings at the command line, you use:

-M "logstash.log.var.paths=[/path/to/log/logstash/logstash-server.log*]" -M "logstash.slowlog.var.paths=[/path/to/log/logstash/logstash-slowlog.log*]"

Variable settings

Each fileset has separate variable settings for configuring the behavior of the module. If you don’t specify variable settings, the logstash module uses the defaults.

For more information, see Configure variable settings. Also see Override input settings.

When you specify a setting at the command line, remember to prefix the setting with the module name, for example, logstash.log.var.paths instead of log.var.paths.

log fileset settings

var.paths
An array of glob-based paths that specify where to look for the log files. All patterns supported by Go Glob are also supported here. For example, you can use wildcards to fetch all files from a predefined level of subdirectories: /path/to/log/*/*.log. This fetches all .log files from the subfolders of /path/to/log. It does not fetch log files from the /path/to/log folder itself. If this setting is left empty, Filebeat will choose log paths based on your operating system.
var.format
The configured Logstash log format. Possible values are: json or plain. The default is plain.

slowlog fileset settings

var.paths
An array of glob-based paths that specify where to look for the log files. All patterns supported by Go Glob are also supported here. For example, you can use wildcards to fetch all files from a predefined level of subdirectories: /path/to/log/*/*.log. This fetches all .log files from the subfolders of /path/to/log. It does not fetch log files from the /path/to/log folder itself. If this setting is left empty, Filebeat will choose log paths based on your operating system.
var.format
The configured Logstash log format. Possible values are: json or plain. The default is plain.

Timezone support

This module parses logs that don’t contain timezone information. For these logs, Filebeat reads the local timezone and uses it when parsing to convert the timestamp to UTC. The timezone to be used for parsing is included in the event in the event.timezone field.

To disable this conversion, the event.timezone field can be removed with the drop_fields processor.

If logs are originated from systems or applications with a different timezone to the local one, the event.timezone field can be overwritten with the original timezone using the add_fields processor.

See Processors for information about specifying processors in your config.

Example dashboards

This module comes with two sample dashboards.

kibana logstash log
kibana logstash slowlog

Fields

For a description of each field in the module, see the exported fields section.