Hadoop UI shows only one Datanode

Question

I\'ve started hadoop cluster composed of on master and 4 slave nodes.

Configuration seems ok:

hduser@ubuntu-amd64:/usr/local/hadoop$ ./bin/hdfs dfsadmin -rep

Answer 1

The following tips may help you

1. Check the core-site.xml and ensure that the namenode hostname is correct
2. Check the firewall rules in namenode and datanodes and ensure that the required ports are open
3. Check the logs of datanodes
4. Ensure that all the datanodes are up and running