Why Cron cartridge does not have access to mysql cartridge environment variables in OpenShift?

Issue

After write a cron job that uses OPENSHIFT_MYSQL_* environment variables it returned an error because they were not set. Below is the example script:

#!/bin/bash

env | grep OPENSHIFT_MYSQL >> ${OPENSHIFT_RUBY_LOG_DIR}/env.log

After the cron job runs the content of env.log is blank. This only happen when the application was set to autoscaling.

Is there a way to make this work?