Hadoop HDFS namenode

Utility to Run NameNode in Hadoop

Using hdfs namenode command.

  

Eg.

Runs the namenode. More info about the upgrade, rollback and finalize is at Upgrade Rollback.

   Usage: hdfs namenode [-backup] |
          [-checkpoint] |
          [-format [-clusterid cid ] [-force] [-nonInteractive] ] |
          [-upgrade [-clusterid cid] [-renameReserved<k-v pairs>] ] |
          [-upgradeOnly [-clusterid cid] [-renameReserved<k-v pairs>] ] |
          [-rollback] |
          [-rollingUpgrade <downgrade|rollback> ] |
          [-finalize] |
          [-importCheckpoint] |
          [-initializeSharedEdits] |
          [-bootstrapStandby] |
          [-recover [-force] ] |
          [-metadataVersion ]
COMMAND_OPTION	Description
-backup	Start backup node.
-checkpoint	Start checkpoint node.
-format [-clusterid cid] [-force] [-nonInteractive]	Formats the specified NameNode. It starts the NameNode, formats it and then shut it down. -force option formats if the name directory exists. -nonInteractive option aborts if the name directory exists, unless -force option is specified.
-upgrade [-clusterid cid] [-renameReserved<k-v pairs>]	Namenode should be started with upgrade option after the distribution of new Hadoop version.
-upgradeOnly [-clusterid cid] [-renameReserved<k-v pairs>]	Upgrade the specified NameNode and then shutdown it.
-rollback	Rollback the NameNode to the previous version. This should be used after stopping the cluster and distributing the old Hadoop version.
-rollingUpgrade <downgrade|rollback|started>	See Rolling Upgrade document for the detail.
-finalize	Finalize will remove the previous state of the files system. Recent upgrade will become permanent. Rollback option will not be available anymore. After finalization it shuts the NameNode down.
-importCheckpoint	Loads image from a checkpoint directory and save it into the current one. Checkpoint dir is read from property fs.checkpoint.dir
-initializeSharedEdits	Format a new shared edits dir and copy in enough edit log segments so that the standby NameNode can start up.
-bootstrapStandby	Allows the standby NameNode's storage directories to be bootstrapped by copying the latest namespace snapshot from the active NameNode. This is used when first configuring an HA cluster.
-recover [-force]	Recover lost metadata on a corrupt filesystem. See HDFS User Guide for the detail.
-metadataVersion	Verify that configured directories exist, then print the metadata versions of the software and the image.

Input:
Result: