I resolved the issue. In the .log file I kept seeing:
(DataNode.java:2402)
2015-05-14 11:49:51,657 WARN datanode.DataNode (DataNode.java:checkStorageLocations(2284)) - Invalid dfs.datanode.data.dir /mnt/Data3/hadoop/hdfs :
EPERM: Operation not permitted
at org.apache.hadoop.io.nativeio.NativeIO$POSIX.chmodImpl(Native Method)
at org.apache.hadoop.io.nativeio.NativeIO$POSIX.chmod(NativeIO.java:230)
at org.apache.hadoop.fs.RawLocalFileSystem.setPermission(RawLocalFileSystem.java:726)
First off, the hadoop/hdfs directory was not created. So i created that, and then did a chown -R hdfs:hadoop to the hdfs directory and now the datanodes work.
So it seems as though Ambari does not set this up during the install which I mistakenly thought. So I’ll have to go through every component, find where the configurations don’t line up and manually do some installation fixes.
Thanks for the guidance