Hadoop start up error

[Frank Astier]

Hi -

I’m seeing the following exception while trying to start MiniDFSCluster in some 
environment. The stack trace is:

   Starting DataNode 0 with dfs.data.dir: 
build/test/data/dfs/data/data1,build/test/data/dfs/data/data2
   java.lang.NullPointerException
    at 
org.apache.hadoop.hdfs.MiniDFSCluster.startDataNodes(MiniDFSCluster.java:413)
    at org.apache.hadoop.hdfs.MiniDFSCluster.<init>(MiniDFSCluster.java:274)
    at org.apache.hadoop.hdfs.MiniDFSCluster.<init>(MiniDFSCluster.java:122)
    at 
com.yahoo.ads.ngdstone.tpbdm.BDMTestCase.oneTimeSetUp(BDMTestCase.java:69)

My code is:

        System.setProperty("hadoop.log.dir", "/tmp");
        System.setProperty("dfs.permissions.supergroup", "su");

            conf = new Configuration();
            dfsCluster = new MiniDFSCluster(conf, 1, true, null);      // <== 
Line 69 in BDMTestCase.java
            fs = dfsCluster.getFileSystem();

...

Line 413 in MiniDFSCluster is:

   String  ipAddr = dn.getSelfAddr().getAddress().getHostAddress();

So I’m guessing it has something to do with the network setup?? - I see just 
above in MiniDFSCluster:

    conf.set("dfs.datanode.address", "127.0.0.1:0");
    conf.set("dfs.datanode.http.address", "127.0.0.1:0");
    conf.set("dfs.datanode.ipc.address", "127.0.0.1:0");

Do I need to have those ports available/enabled in my environment? Is that the 
problem here?

Thanks!

Frank