Hdfs can be accessed in R by specifying namenode host (hdfs://<hostname>:/user/test), but in case of namenode failover it won't work. So we should set hdfs config directory in R so it recognizes the hadoop namenode and failover configurations..
Set Hadoop and Spark home and config directories into R environment as below:
# set up the SPARK_HOME
#set up the HADOOP config dir
# read the data file
sc = sparkR.init(sparkPackages="com.databricks:spark-csv_2.11:1.0.3")
sqlContext = sparkRSQL.init(sc)
people = read.df(sqlContext, "hdfs://HDFS-HA/users/people.json", "json")