Hadoop config files support Variable Expansion as described [here](https://hadoop.apache.org/docs/current/api/org/apache/hadoop/conf/Configuration.html).
However, when trying to use this for cdap system properties, it appears the container localization uses the raw value from cdap-site.xml rather than the interpolated value. For example, trying to dynamically set kafka.seed.brokers results in the following line in the container's cConf.xml:
and the container fails to start.
We should support this functionality of hadoop, which makes it possible to parameterize cdap-site.xml.