Useful Command for cluster management

#Commands to check cluster health

Check whether ResourceManager & NodeManager are running or not (Part of HDFS and YARN)

ps -ef | grep -i manager

Check whether NameNode, DataNode & SecondaryNameNode are running or not

ps -ef | grep -i node

HDFS services running under this user (NameNode, DataNode & SecondaryNameNode service)

ps -fu hdfs

YARN services running under this user (ResourceManager & NodeManager service)

ps -fu yarn

To search commands using VI history

set -o vi

jdbc:mysql://quickstart.cloudera.3306 --> JDBC URL
hdfs://quickstart.cloudera:8020 --> NameNode URL

#Check service running

cat /etc/passwd (it will list all available users)
sudo -u yarn jps (to list hdfs services)
sudo -u hdfs jps (to list yarn services)

#JPS

sudo -u hdfs jps
sudo -u yarn jps

#EOF usage

hive <<EOF
show databases;
show tables;
EOF

Source : Copy pasted found somewhere