How hadoop2.7 Cluster migrates namenode

This article mainly introduces how the hadoop2.7 cluster migrates namenode. It is very detailed and has certain reference value. Friends who are interested must finish reading it.

My hadoop cluster is a 2.7.0 cluster.

Hadoop is machine-independent. If you migrate namenode, you can follow these steps.

1. Close all hadoop clusters, zookeeper, hive and hbase clusters, set hosts and ssh mutual trust, and adjust server time.

2. Copy the directory of hadoop and the corresponding data directory to the new namenode host, and keep the directory of the old and new host the same.

3. Modify the configuration file under $HADOOP_HOME/etc/hadoop/:

The hostname of namenode in core-site.xml, hdfs-site.xml, mapred-site.xml, master, slaves, yarn-site.xml and other files is changed to the hostname of the new host.

4. Make sure that all datanode nodes have also modified the configuration file in step 3.

5. Modify the configuration file zoo.cfg in zookeeper

6. Modify the configuration file hbase-site.xml in hbase

7. Modify the configuration file of hive, if there is any modification in zookeeper. At the same time, hive also needs to modify mysql's data records about namenode configuration information. Perform the following sql:

Update DBS set DB_LOCATION_URI=REPLACE (DB_LOCATION_URI,'old host','new host')

Update SDS set LOCATION=REPLACE (LOCATION,'old host','new host')

After starting hadoop, zookeeper, hbase, hive, check to see if the modification is successful.

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