YARN Application Master unable to connect to Resource Manager

Question

I have a 4 node cluster (1 Namenode/Resource Manager 3 datanodes/node managers)

I am trying to run a simple tez example orderedWordCount

hadoop jar          


        

Answer 1

It might be possible that your ResourceManager is listening on an IPv6 Port while your worker nodes (i.e NodeManagers) might be using IPv4 to connect to the ResourceManager

To quickly check if this is the case, do a

netstat -aln | grep 8030

If you get something similar to :::8030, then your ResourceManager is indeed listening on an IPv6 Port. If its a IPv4 port, you should see something similar to 0.0.0.0:8030

To fix this, you might want to consider disabling IPv6 on all your machines and try once again.