Setup
Graylog Audit Log is a commercial feature that can be installed inaddition to the Graylog open source server.
Installation​
Audit Log functionality is part of the Graylog Enterprise plugin, please checkthe Graylog Enterprise setup page for details on howto install it.
Configuration​
Graylog Audit Log provides two ways of writing audit log entries:
- Database
- Log file via log4j2 appender
Logging to the database is always enabled and cannot be disabled.
Note
All configuration needs to be done in the Graylog server configuration file and in the logging configuration. (only if the log4j2 appender is enabled)Check the default file locations page for details.
The web interface can show the current configuration.
Database Configuration Options​
The default MongoDB audit log has a few configuration options available.
Configuration Options
| Name | Description |
|---|---|
auditlog_mongodb_keep_entries | delete audit log entries older that configured interval |
auditlog_mongodb_cleanup_interval | interval of the audit log entry cleanup job |
auditlog_mongodb_collection | the MongoDB collection to store the audit log entries in |
auditlog_mongodb_keep_entries​
This configures the interval after which old audit log entries in the MongoDBdatabase will be deleted. You have to use values like 90d(90 days) toconfigure the interval.
Warning
Make sure to configure this to fit your needs. Deleted audit log entries are gone forever!
The default value for this is 365d.
Example:
auditlog_mongodb_keep_entries = 365d
auditlog_mongodb_cleanup_interval​
This configures the interval of the background job that periodically deletesold audit log entries from the MongoDB database. You have to use values like 1h(1 hour) to configure the interval.The default value for this is 1h.
Example:
auditlog_mongodb_cleanup_interval = 1h
auditlog_mongodb_collection​
This configures the name of the MongoDB collection where audit log entries willbe stored.
The default value for this is audit_log.
Example:
auditlog_mongodb_collection = audit_log
Log4j2 Configuration Options​
The optional log4j2 audit log appender has a few configuration options available.
Note
To configure the log4j2 appender you have to edit the Graylog server configuration file and the log4j2.xml file for your setup!
Configuration Options
| Name | Description |
|---|---|
auditlog_log4j_enabled | whether the log4j2 appender is enabled or not |
auditlog_log4j_logger_name | log4j2 logger name |
auditlog_log4j_marker_name | log4j2 marker name |
auditlog_log4j_enabled​
The log4j2 audit log appender is disabled by default and can be enabled bysetting this option to true.
The default value for this is false.
Example:
auditlog_log4j_enabled = true
auditlog_log4j_logger_name​
This configures the log4j2 logger name of the audit log.
The default value for this is gl-org.graylog.plugins.auditlog.
Example:
auditlog_log4j_logger_name = graylog-auditlog
auditlog_log4j_marker_name​
This configures the log4j2 marker name for the audit log.
The default value for this is AUDIT_LOG.
Example:
auditlog_log4j_marker_name = AUDIT_LOG
Log4j2 Appender Configuration​
To write audit log entries into a file you have to enable the log4j2 appenderin your Graylog configuration file and add some configuration to the log4j2.xmlfile that is used by your server process.
The log4j2.xmlfile location is dependent on your deployment method.so please check the default file locations page.
An existing log4j2.xmlconfig file needs another <Logger/>statementin the <Loggers/>section and an additional appender in the <Appenders/>section of the file.
Warning
The file on your system might look different than the following example. Make sure to only add the audit log related snippets to your config and do not remove anything else!
Example log4j2.xmlfile with audit log enabled:
<?xml version="1.0" encoding="UTF-8"?>
<Configuration packages="org.graylog2.log4j" shutdownHook="disable">
<Appenders>
<!-- Graylog server log file appender -->
<RollingFile name="rolling-file" fileName="/var/log/graylog-server/server.log" filePattern="/var/log/graylog-server/server.log.%i.gz">
<PatternLayout pattern="%d{yyyy-MM-dd'T'HH:mm:ss.SSSXXX} %-5p [%c{1}] %m%n"/>
<Policies>
<SizeBasedTriggeringPolicy size="50MB"/>
</Policies>
<DefaultRolloverStrategy max="10" fileIndex="min"/>
</RollingFile>
<!-- ##################################################### -->
<!-- Rotate audit logs daily -->
<RollingFile name="AUDITLOG" fileName="/var/log/graylog-server/audit.log" filePattern="/var/log/graylog-server/audit-%d{yyyy-MM-dd}.log.gz">
<PatternLayout>
<Pattern>%d - %m - %X%n</Pattern>
</PatternLayout>
<Policies>
<TimeBasedTriggeringPolicy />
</Policies>
</RollingFile>
<!-- ##################################################### -->
</Appenders>
<Loggers>
<Logger name="org.graylog2" level="info"/>
<!-- ##################################################### -->
<!-- Graylog Audit Log. The logger name has to match the "auditlog_log4j_logger_name" setting in the Graylog configuration file -->
<Logger name="graylog-auditlog" level="info" additivity="false">
<AppenderRef ref="AUDITLOG"/>
</Logger>
<!-- ##################################################### -->
<Root level="warn">
<AppenderRef ref="rolling-file"/>
</Root>
</Loggers>
</Configuration>
The config snippets between the <!-- ######### -->tags have been addedto the existing log4j2.xmlfile.
Make sure that the namein the <Logger />tag matches the configuredauditlog_log4j_logger_namein your Graylog server configuration. Otherwiseyou will not see any log entries in the log file.
Caveats​
You have to make sure that the log4j2 related settings in the Graylog serverconfig file and the log4j2.xmlfile are the same on every node in your cluster !
Since every Graylog server writes its own audit log entries when the GraylogEnterprise plugin is installed, the log files configured in the log4j2.xmlfile are written on every node. But only the entries from the local nodewill show up in that file.
If you have more than one node, you have to search in all configured fileson all nodes to get a complete view of the audit trail.