how are cassandra conf folders updated from default.conf when running the cassandra image?

[krishna81m]

As a Docker newbie, posted an issue at moby/moby#19381 (comment) thinking it was a windows docker container issue and assuming this script is used "only once" (correct me if I am wrong) to build

cassandra/cassandra/src/start.sh

Lines 23 to 32 in f46e178

	rm -rf $CONFIG && cp -r $DEFAULT $CONFIG
	sed -i -e "s/^listen_address.*/listen_address: $IP/" $CONFIG/cassandra.yaml
	sed -i -e "s/^rpc_address.*/rpc_address: 0.0.0.0/" $CONFIG/cassandra.yaml
	sed -i -e "s/# broadcast_address.*/broadcast_address: $IP/" $CONFIG/cassandra.yaml
	sed -i -e "s/# broadcast_rpc_address.*/broadcast_rpc_address: $IP/" $CONFIG/cassandra.yaml
	sed -i -e "s/^commitlog_segment_size_in_mb.*/commitlog_segment_size_in_mb: 64/" $CONFIG/cassandra.yaml
	sed -i -e "s/- seeds: \"127.0.0.1\"/- seeds: \"$SEEDS\"/" $CONFIG/cassandra.yaml
	sed -i -e "s/# JVM_OPTS=\"\$JVM_OPTS -Djava.rmi.server.hostname=<public name>\"/JVM_OPTS=\"\$JVM_OPTS -Djava.rmi.server.hostname=$IP\"/" $CONFIG/cassandra-env.sh
	sed -i -e "s/LOCAL_JMX=yes/LOCAL_JMX=no/" $CONFIG/cassandra-env.sh
	sed -i -e "s/JVM_OPTS=\"\$JVM_OPTS -Dcom.sun.management.jmxremote.authenticate=true\"/JVM_OPTS=\"\$JVM_OPTS -Dcom.sun.management.jmxremote.authenticate=false\"/" $CONFIG/cassandra-env.sh

an initial image.

After the image runs as a container and then you make a change in etc/cassandra/conf/cassandra.yaml and save/start the container, the changes are overriden from etc/cassandra/default.conf/cassandra.yaml. I am unable to find or figure out where and how this is happening.