Hi, I was confused by the configuration and file system in hadoop. when we create a FileSystem object and read/write something through it, are we writing to or reading from HDFS? Could it be local file system? If yes, what determines which file system it is? Configuration object we used to create the FileSystem object? When I write mapreduce program which "extends Configured implements Tool", I can get the right configuration by calling getConf() and use the FileSystem object to communicate with HDFS. What if I want to read/write HDFS in a separate Utility class? Where does the configuration come from?
Thanks. -Gang
