Multiple servers in spark-defaults.conf

Question

I have a Cloudera (Cloudera Express 5.4.1 (#197 built by jenkins on 20150509-0041 git: 003e06d761f80834d39c3a42431a266f0aaee736)) with Spark installed on it. I want the spark-defaults.conf to have 2 servers defined. How do we carry it out?

spark.eventLog.dir=hdfs://XXXX:8020/user/spark/applicationHistory
spark.eventLog.enabled=true
spark.yarn.historyServer.address=http://XXXX:18088

I want it to be like

spark.eventLog.dir={hdfs://XXXX:8020/user/spark/applicationHistory,hdfs://YYYY:8020/user/spark/applicationHistory}
spark.eventLog.enabled=true
spark.yarn.historyServer.address={http://XXXX:18088, http://YYYY:18088}