NodeManager is not able to connect to the ResourceManager

Question

I have a up and running Hadoop cluster which has 4 nodes. But whenever I am executing a MapReduce program, I only see 1 active node from which I am submitting the job. But when I see my resource manager’s the error log, I see this:

yarn-deploy-nodemanager-master.log:
INFO org.apache.hadoop.yarn.client.RMProxy: Connecting to ResourceManager at /0.0.0.0:8032

Where can I find this property which allocates ResourceManager the address 0.0.0.0:8032? So, can anyone help me out in understanding the error?

Answer 1

Here, I guess the issue is with the firewall. The ResourceManager port to which the NodeManagers are trying to connect is blocked. Firewall may be blocking resource manager’s port. You can turn off the firewall. But, I would recommend you to only open the 8032 port of the ResouceManager.