jps only shows Java processes on the current host. Judging by the ping times, I'm guessing the NameNode is not the host you ran these commands from? If you're using Cloudera Manager you can browse the logs and see the status of the processes in the web UI. If you installed CDH from packages you can check the status of the process on the machine it should be running on with 'sudo service hadoop-hdfs-namenode status' (and restart it with 'sudo service hadoop-hdfs-namenode restart'). You can find the log files in /var/log/hadoop-hdfs to see why it's failing, if it is.