I was trying Datatorrent sandbox but was getting this error ....
HDFS Not Ready HDFS may still be starting up, or there may be other configuration issues with your hadoop services.
The console checks for changes in the status of these services every 10 seconds, but you can also trigger a refresh manually.
Adding Env Details :
OS : Ubuntu 14.04
virtual box : virtualbox-5.0_5.0.18-106667
datatorrent : datatorrent-sandbox-3.2.0