No, you do not have to re-install CDH. Here is a document that shows you how to move Cloudera Manager to a new host and steps to take so your CDH hosts will see it. http://www.cloudera.com/documentation/enterprise/latest/topics/cm_ag_restore_server.html Moving the Cloudera Manager Server to a New Host You can move the Cloudera Manager Server if either the Cloudera Manager database server or a current backup of the Cloudera Manager database is available. To move the Cloudera Manager Server: Identify a new host on which to install Cloudera Manager. Install Cloudera Manager on a new host, using the method described under Install the Cloudera Manager Server Packages. Important: The Cloudera Manager version on the destination host must match the version on the source host. Do not install the other components, such as CDH and databases. Copy the entire content of /var/lib/cloudera-scm-server/ on the old host to that same path on the new host. Ensure you preserve permissions and all file content. If the database server is not available: Install the database packages on the host that will host the restored database. This could be the same host on which you have just installed Cloudera Manager or it could be a different host. If you used the embedded PostgreSQL database, install the PostgreSQL package as described in Embedded PostgreSQL Database. If you used an external MySQL, PostgreSQL, or Oracle database, reinstall following the instructions in Cloudera Manager and Managed Service Datastores. Restore the backed up databases to the new database installation. Update /etc/cloudera-scm-server/db.properties with the database name, database instance name, username, and password. Do the following on all cluster hosts: In /etc/cloudera-scm-agent/config.ini, update the server_host property to the new hostname. If you are replacing the Cloudera Manager database with a new database, and you are not using a backup of the original Cloudera Manager database, delete the /var/lib/cloudera-scm-agent/cm_guid file. Restart the agent using the following command: $ sudo service cloudera-scm-agent restart Start the Cloudera Manager Server. Cloudera Manager should resume functioning as it did before the failure. Because you restored the database from the backup, the server should accept the running state of the Agents, meaning it will not terminate any running processes. The process is similar with secure clusters, though files in /etc/cloudera-scm-server must be restored in addition to the database. See Cloudera Security.
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