QDB configuration is optional. The defaults launch a server listening on 127.0.0.1:9554 with no security. This is appropriate for many applications. On startup QDB looks for a qdb.conf or qdb.properties file in /etc and the current directory with settings the latter having priority. Example /etc/qdb.properties:
For an up-to-date listing of configuration properties and default values please look at qdb-default.conf in the source code.
The startup scripts define QDB_SERVER_OPTS="-server" and source /etc/default/qdb for overrides. These options are passed to the "java" command that runs QDB. You might want to configure memory usage. Example /etc/default.qdb:
QDB logs messages to the console by default, which the startup scripts redirect to /var/log/qdb/qdb.log (Linux) or to ./qdb.log (Generic). GELF logging to a Graylog2 server is also supported. Sample /etc/qdb.properties: