I set up and configured a multi-node Hadoop cluster using this tutorial.
When I type in the start-all.sh command, it shows all the processes initializing properly as
I was having the same problem running a single-node pseudo-distributed instance. Couldn't figure out how to solve it, but a quick workaround is to manually start a DataNode with hadoop-x.x.x/bin/hadoop datanode
hadoop-x.x.x/bin/hadoop datanode