Advanced log configuration

GeoServer logging subsystem is based on Java logging, which is in turn by default redirected to Log4J and controlled by the current logging configuration set in the Global Settings.

The standard configuration can be overridden in a number of ways to create custom logging profiles or to force GeoServer to use another logging library altogheter.

Custom logging profiles

Anyone can write a new logging profile by adding a Log4J configuration file to the list of files already available in the $GEOSERVER_DATA_DIR/logs folder. The name of the file will become the configuration name displayed in the admin console and the contents will drive the specific behavior of the logger.

Here is an example, taken from the GEOTOOLS_DEVELOPER_LOGGING configuration, which enables the geotools log messages to appear in the logs:

log4j.rootLogger=WARN, geoserverlogfile, stdout

log4j.appender.stdout.layout.ConversionPattern=%d{dd MMM HH:mm:ss} %p [%c] - %m%n


# Keep three backup files.
# Pattern to output: date priority [category] - message
log4j.appender.geoserverlogfile.layout.ConversionPattern=%d %p [%c] - %m%n
# Some more geotools loggers you may be interest in tweaking

Any custom configuration can be setup to enable specific packages to emit logs at the desired logging level. There are however a few rules to follow:

  • the configuration should always include a geoserverlogfile appender that GeoServer will configure to work against the location configured in the Global Settings
  • a logger writing to the standard output should be called stdout and again GeoServer will enable/disable it according to the configuration set in the Global Settings
  • it is advisable, but not require, to setup log rolling for the geoserverlogfile appender

Overriding the log location setup in the GeoServer configuration

When setting up a cluster of GeoServer machines it is common to share a single data directory among all the cluster nodes. There is however a gotcha, all nodes would end up writing the logs in the same file, which would cause various kinds of troubles depending on the operating system file locking rules (a single server might be able to write, or all togheter in an uncontrolled manner resulting in an unreadable log file).

In this case it is convenient to set a separate log location for each GeoServer node by setting the following parameter among the JVM system variables, enviroment variables, or servlet context parameters:

GEOSERVER_LOG_LOCATION=<the location of the file>

A common choice could be to use the machine name as a distinction, setting values such as logs/geoserver_node1.log, logs/geoserver_node2.log and so on: in this case all the log files would still be contained in the data directory and properly rotated, but each server would have its own separate log file to write on.

Forcing GeoServer to relinquish Log4J control

GeoServer internally overrides the Log4J configuration by using the current logging configuration as a template and appling the log location and standard output settings configured by the administrator.

If you wish GeoServer not to override the normal Log4J behavior you can set the following parameter among the JVM system variables, enviroment variables, or servlet context parameters:


Forcing GeoServer to use an alternate logging redirection

GeoServer uses the GeoTools logging framework, which in turn is based on Java Logging, but allowing to redirect all message to an alternate framework of users choice.

By default GeoServer setups a Log4J redirection, but it is possible to configure GeoServer to use plain Java Logging or Commons Logging instead (support for other loggers is also possible by using some extra programming).

If you wish to force GeoServer to use a different logging mechanism set the following parameters among the JVM system variables, enviroment variables, or servlet context parameters:


As noted in the example you’ll also have to demand that GeoServer does not exert control over the Log4J configuration