kafka application logdir

How do I configure the application kafka log dir?

Right now the default is /var/log/upstart/kafka.log . I want to point it to
a different mount dir... e.g.

/opt/kafka/bin/kafka-server-start.sh /opt/kafka/config/server.properties
--logdir /mnt/kafka/kafka-app-logs

But the above gives me errors :

USAGE: java [options] KafkaServer server.properties

NOTE: these are application log dir , not the data directory.

Any recommended way to point the application log to a different place?

thx

jim