Thursday, May 29, 2014

Step by step instruction how Start/Stop & manage each Hadoop Daemons in distributed Hadoop environment

Step by step instruction how Start/Stop Hadoop Daemons
 Refer setting up sudo/single node Hadoop 2.X
This post will help you out how to start & stop the Hadoop daemons from master & slave nodes.
All the file available under $HADOOP_PATH/sbin
start-all.sh & stop-all.sh 
           Used to start and stop hadoop daemons all at once. Issuing it on the master machine will start/stop the daemons on all the nodes of a cluster. 
Hadoop daemons are
NameNode                 
SecondaryNameNode   
ResourceManager
JobHistoryServer
DataNode
NodeManager

start-dfs.sh, stop-dfs.sh 
           start/stop only  HDFS daemons separately on all the nodes from the master machine. (HDFS Daemons are NameNode , SecondaryNameNode and DataNode )
in master node
NameNode 
SecondaryNameNode  
in slave node
DataNode
start-yarn.sh, stop-yarn.sh 
           start/stop YARN daemons separately on all the nodes from the master machine. (YARN daemons are ResourceManager and NodeManager )
in master node
ResourceManager
in slave node
NodeManager
Start individual Hadoop daemons
hadoop-daemon.sh namenode/datanode &
yarn-deamon.sh resourcemanager/nodemanager 
         To start individual daemons on an individual machine manually. You need to go to a particular node and issue these commands.
sbin/hadoop-daemon.sh start datanode 
Use case : In distributed Hadoop cluster  Suppose you have added a new DataNode to your cluster and you need to start the DataNode daemon only on this machine.
all the DataNode in cluster can start from server
sbin/hadoop-daemons.sh start datanode
Use case : In distributed Hadoop cluster  Suppose you want stop/start all the  DataNode in your cluster from master node.
to start histroyserver by
 sbin/mr-jobhistory-daemon.sh start historyserver

Note :    1) To Start/Stop datanode and nodemanager from master, script is *-daemons.sh and not *-daemon.sh. daemon.sh does not lookup in slaves file and hence, will only start processes on master
          2) You should have ssh enabled if you want to start all the daemons on all the nodes from one machine.
Post a Comment