Log Viewer allows you to do the following:
You can access the Log Viewer tool directly in a web browser at http://<host>:<port>/system/console/logs
By default, the Log Viewer shows log files under the default log file path <cq_home>/crx-quickstart/logs. If you customized your log file locations, configure logtail.paths with a value equal to the absolute file system path from which logs can be tailed and downloaded.
To configure this change, do the following:
Alternatively, you can create a repository-based OSGi configuration. See here for details on how to create such a configuration.