Log content autodiscovery

Log Monitoring Classic

By default, Dynatrace automatically discovers all new log files that meet the requirements described below.

Default autodiscovery

Dynatrace automatically discovers, analyzes, and stores (if selected for storage) logs every 60 seconds.
Note: Whether your autodiscovered files are stored in Dynatrace depends on the log storage configuration.

By default, the OneAgent log module autodiscovers the following categories of log files:

• System logs
  On Windows:

  • Windows Security Log
  • Windows Application Log
  • Windows System Log

  On Linux:

  • /var/log/messages
  • /var/log/syslog

• Log files opened by running processes. For details, see Log content autodiscovery

• IIS Logs (Windows only) - both event logs and plain log files

• Container logs (Linux only) in Kubernetes, Openshift, and non-instrumented Docker. For details, see Log Monitoring in Kubernetes

Attributes selected in Windows event logs

For Windows event logs, Log Monitoring selects the following attributes:

Autodiscovery requirements

A log file must meet all of the following requirements in order to be autodiscovered:

• The log file must be opened by an important process.

• The log file must exist for a minimum of one minute.

• The logs must have a supported character encoding. By default, the supported encoding is UTF-8. Other supported types include UTF-8 BOM and, if the files contain the byte-order mark (BOM), UTF-16LE and UTF-16BE.

  Binary logs and unsupported timestamp

  Binary log files are not analyzed and stored (only the file status is reported). Files with an unsupported timestamp are automatically timestamped with the file reading time.

• The log file must be at least 0.5 KB in size.

• The log file must have been updated (written to) in the last 7 days.
  Log files that have not been updated in the past 7 days while Log Monitoring is active will not be visible on dashboards.

• The log file must be in the actual log or logs folder or in its subfolders:

  • Valid path examples:
    c:\log\log_file.txt
c:\logs\NewFolder\log_file.txt
  • Invalid path example:
    c:\log\NewFolder\NewFolder\log_file.txt

  or the log filename must contain a log string preceded or followed by the period (.) or underscore (_) character:

  • Valid filename examples:
    c:\NewFolder\abc.log
c:\NewFolder\0865842.log.txt
  • Invalid filename example:
    c:\NewFolder\logfile.txt

Turn off log autodiscovery

If you don't want Dynatrace to automatically discover new log files on a specific monitored host, you can turn off log autodiscovery.

1. On the host, open the log analytics configuration file for editing.
   • On Linux:
     /var/lib/dynatrace/oneagent/agent/config/ruxitagentloganalytics.conf
   • On Windows:
     %PROGRAMDATA%\dynatrace\oneagent\agent\config\ruxitagentloganalytics.conf
2. Set the following:
   AppLogAutoDetection = false

OneAgent restart is not required.

Limits for your log autodiscovery when using OneAgent.

• Log files in OneAgent cannot be deleted earlier than a minute after creation.
• Log files in OneAgent must be appended (old content is not updated).
• Log files in OneAgent must have text content.
• Log files in OneAgent must be opened constantly (not just for short periods of adding log entry).
• Log files in OneAgent must be opened in write mode.

Unsupported autodiscovery scenarios

Scenarios that are not supported in the rotated log autodiscovery process include:

• Rotated log generation with a directory change. This process could lead to the creation of numerous non-aggregated and/or incomplete logs, as well as to resource overuse.
• Rotated log generation with immediate compression, where the application addresses a file with the same name. If a rotation criterion is met (for example, the required file size is reached), the file is moved to another location and immediately compressed. Example: /var/log/application.log -> /var/log/application.log.1.gz -> /var/log/application.log.2.gz -> /var/log/application.log.3.gz. This process might again lead to incomplete log creation.

Related topics

Log Monitoring FAQ