How to start and stop Hadoop

This article mainly introduces how to start and stop Hadoop, has a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, the following let the editor take you to understand it.

Version Hadoop-1.2.1

Startup script description

Start-all.sh starts all Hadoop daemons. Including NameNode, SecondaryNameNode, DataNode, JobTracker, TaskTrack

Stop-all.sh stops all Hadoop daemons. Including NameNode, SecondaryNameNode, DataNode, JobTracker, TaskTrack

Start-dfs.sh starts the Hadoop HDFS daemon NameNode, SecondaryNameNode, and DataNode

Stop-dfs.sh stops the Hadoop HDFS daemon NameNode, SecondaryNameNode, and DataNode

Hadoop-daemons.sh start namenode starts the NameNode daemon separately

Hadoop-daemons.sh stop namenode stops the NameNode daemon alone

Hadoop-daemons.sh start datanode starts the DataNode daemon separately

Hadoop-daemons.sh stop datanode stops the DataNode daemon alone

Hadoop-daemons.sh start secondarynamenode starts the SecondaryNameNode daemon separately

Hadoop-daemons.sh stop secondarynamenode stops the SecondaryNameNode daemon alone

Start-mapred.sh starts the HadoopMapReduce daemon JobTracker and TaskTracker

Stop-mapred.sh stops the HadoopMapReduce daemon JobTracker and TaskTracker

Hadoop-daemons.sh start jobtracker starts the JobTracker daemon separately

Hadoop-daemons.sh stop jobtracker stops the JobTracker daemon alone

Hadoop-daemons.sh start tasktracker starts the TaskTracker daemon separately

Hadoop-daemons.sh stop tasktracker starts the TaskTracker daemon separately

If the Hadoop cluster is started for the first time, you can use start-all.sh. The more common startup method is a daemon to start, the steps to start are as follows.

1. Start the daemon in the HDFS module of Hadoop

The daemons in HDFS also start in order, that is:

1) start the NameNode daemon

2) start the DataNode daemon

3) start the SecondaryNameNode daemon.

2. Start the daemon in the MapReduce module

The daemons of MapReduce are also started sequentially, that is:

1) start the JobTracker daemon

2) start the TaskTracker daemon.

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