Utility to Run NameNode in Hadoop
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.