How do you know if YARN or Hadoop's NameNode services are running or not?
Use the "sudo jps" command. Some Linux users may not have sufficient permissions to install it.
If the command is not found, go to the option below for your distribution of Linux:
If you are running a RedHat derivative (e.g., Fedora, CentOS etc.), run this:
sudo yum -y install java-1.8.0-openjdk-devel
# you may prefer to use java-1.7.0-openjdk-devel
If you are running Ubuntu or a Debian distribution, run this:
sudo apt-get -y install apt-get install openjdk-8-jre
# you may prefer to use openjdk-7-jre
To interpret the output of a "sudo jps" command, here is an example of jps output where the NameNode is running but Yarn is not:
Here is an example of Yarn running but not the name node: