namenode

Runs the NameNode.

The usage is as follows:

$ 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 <rollback |started> ] |
          [-importCheckpoint] |
          [-initializeSharedEdits] |
          [-bootstrapStandby [-force] [-nonInteractive] [-skipSharedEditsCheck] ] |
          [-recover [-force] ] |
          [-metadataVersion ]
Arguments

-backup

Starts the Backup node

-checkpoint

Starts a Checkpoint node

-format [-clusterid cid]

Formats the specified NameNode. It starts the NameNode, formats it and then shuts it down. Will throw NameNodeFormatException if the directory already exists and if reformatting is disabled for the cluster

-upgrade [-clusterid cid] [-renameReserved <k-v pairs>]

NameNode should be started with the upgrade option after the distribution of a new Arenadata Hadoop version

-upgradeOnly [-clusterid cid] [-renameReserved <k-v pairs>]

Upgrades the specified NameNode and then shuts it down

-rollback

Rolls back a NameNode to the previous version. This should be used after stopping the cluster and distributing the old Arenadata Hadoop version

-rollingUpgrade <rollback|started>

When a rolling upgrade is in progress, the -rollingUpgrade NameNode startup option is used to specify various rolling upgrade options:

  • rollback: restores the NameNode back to the pre-upgrade release and also reverts the user data back to the pre-upgrade state;

  • started: specifies a rolling upgrade already started so that the NameNode should allow image directories with different layout versions during startup.

-importCheckpoint

Loads an image from a checkpoint directory and saves it into the current one. Checkpoint dir is read from property dfs.namenode.checkpoint.dir

-initializeSharedEdits

Formats a new shared edits dir and copies to available edit log segments so that the Standby NameNode can start up

-bootstrapStandby [-force] [-nonInteractive] [-skipSharedEditsCheck]

Allows a 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. The option -force or -nonInteractive has the same meaning as described in the namenode -format command

-recover [-force]

Recovers lost metadata on a corrupt filesystem

-metadataVersion

Verifies that configured directories exist, then prints the metadata versions of the software and the image

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