mmhdfs command

The mmhdfs command configures and manages the IBM Spectrum Scale HDFS Transparency components.

Synopsis

mmhdfs {hdfs | hdfs-nn | hdfs-dn} {start | stop | restart | status}

mmhdfs {namenode | datanode} {start | stop | restart | status} [-N Node[,Node...]]

mmhdfs config upload

mmhdfs config set {filename} {-k key1=value1[ -k key2=value2...]}

mmhdfs config del {filename} {-k key1[ -k key2...]}

mmhdfs config get {filename} {-k key1[ -k key2...]}

mmhdfs config import [--nocheck] {dirpath} {filename1[,filename2...] | all}

mmhdfs config export [--nocheck] {dirpath} {filename1[,filename2...] | all}

mmhdfs worker {add | remove} [Node[,Node...]]

Availability

Available on all IBM Spectrum Scale editions.

Description

Note: From IBM Spectrum Scale 5.0.4.2, the mmhdfs command is available when HDFS Transparency 3.1.1 or later is installed.

Use the mmhdfs command to perform the following:

Start and Stop HDFS Transparency.
Add and Remove the HDFS Transparency worker nodes.
Manage the HDFS Transparency configurations.

Parameters

hdfs

Specifies the NameNode and DataNode service of all the HDFS Transparency nodes.

hdfs-nn

Specifies the NameNode service of all the NameNodes.

hdfs-dn

Specifies the DataNode service of all the DataNodes.

start: Starts the specified component.
stop: Stops the specified component.
restart: Restarts the specified component.
status: Shows the running status of the specified component.

namenode

Specifies the NameNode service of the specified nodes.

datanode

Specifies the DataNode service of the specified nodes.

start: Starts the specified component.
stop: Stops the specified component.
restart: Restarts the specified component.
status: Shows the running status of the specified component.
-N Node[,Node...]: Specifies the nodes on which the command should run.

config

Specifies the configuration operation.

upload

Uploads the configuration into CCR.

set

Sets the specified config option of the specified configuration file to the specified value.

filename: Specifies the name of the file.
-k key1=value1: Specifies the key value pair to set.

del

Deletes the specified config option from the specified configuration file.

filename: Specifies the name of the configuration file.
-k key1: Specifies the key to delete.

get

Gets the value of the specified config option for the specified configuration file.

filename: Specifies the name of the configuration file.
-k key1: Specifies the key to delete.

import

Imports the specified configuration files from the specified directory.

--nocheck: If this option is not specified, only the following configuration files are supported:
hadoop-env.sh, core-site.xml, hadoop-policy.xml, hdfs-site.xml, httpfs-site.xml, gpfs-site.xml, kms-acls.xml, kms-site.xml, ranger-hdfs-audit.xml, ranger-hdfs-security.xml, ranger-policymgr-ssl.xml, ranger-security.xml, ssl-client.xml, ssl-server.xml, yarn-site.xml, kms-log4j.properties, log4j.properties, hadoop-metrics2.properties, and hadoop-metrics.properties slaves workers.
dirpath: Specifies the directory from which to import the files.
filename: Configuration files to be imported.
all: Import all configuration files from the directory.

export

Exports the specified configuration files to the specified directory.

--nocheck: If this option is not specified, only the following configuration files are supported:
hadoop-env.sh, core-site.xml, hadoop-policy.xml, hdfs-site.xml, httpfs-site.xml, gpfs-site.xml, kms-acls.xml, kms-site.xml, ranger-hdfs-audit.xml, ranger-hdfs-security.xml, ranger-policymgr-ssl.xml, ranger-security.xml, ssl-client.xml, ssl-server.xml, yarn-site.xml, kms-log4j.properties, log4j.properties, hadoop-metrics2.properties, and hadoop-metrics.properties slaves workers.
dirpath: Specifies the directory from which to export the files.
filename: Configuration files to be exported.
all: Export all configuration files to the directory.

worker

Adds or removes the DataNode(s).

add: Adds the specified nodes as DataNodes.
remove: Removes the specified nodes from the DataNodes.
Node[,Node...]: Specifies a comma-delimited list of the nodes on which the command should run.

Exit status

0: Successful completion.
nonzero: A failure has occurred.

Security

You must have root authority to run the mmhdfs command.

The node on which the command is issued must be able to execute the remote shell commands on any other node in the cluster without the use of a password and without producing any extraneous messages.

Examples

To start all the HDFS Transparency components, run the following command:
```
mmhdfs hdfs start 
```
To stop all the HDFS Transparency components, run the following command:
```
mmhdfs hdfs stop 
```
To check the HDFS Transparency status for all the Namenodes, run the following command:
```
mmhdfs hdfs-nn status 
```

To add in a configuration setting, run the following command:

mmhdfs config set hadoop-env.sh -k JAVA_HOME=/usr/jdk64/jdk1.8.0_112

mmhdfs config set gpfs-site.xml -k gpfs.mnt.dir=/gpfs -k gpfs.data.dir=trunk -k gpfs.storage.type=local -k gpfs.replica.enforced=gpfs

To get a configuration setting, run the following command:

mmhdfs config get hadoop-env.sh -k JAVA_HOME JAVA_HOME=/usr/jdk64/jdk1.8.0_112

mmhdfs config get core-site.xml -k fs.defaultFS fs.defaultFS=hdfs://hdfscluster

To delete a configuration setting, run the following command:

mmhdfs config del hadoop-env.sh -k JAVA_HOME

mmhdfs config del core-site.xml -k fs.defaultFS

To import configuration files from a local directory, run the following command:
```
mmhdfs config import /tmp/hadoop core-site.xml 
```
To import all configuration files from a local directory, run the following command:
```
mmhdfs config import /tmp/hadoop all
```
To export configuration files to a local directory, run the following command:
```
mmhdfs config export /tmp/hadoop core-siste.xml
```
To export all configuration files to a local directory, run the following command:
```
mmhdfs config export /tmp/hadoop all 
```
To add Datanodes into the HDFS Transparency cluster, run the following command:
```
mmhdfs worker add c902f05x05, c902f05x06, c902f05x07 
```
To upload configuration files into CCR and other nodes, run the following command:
```
mmhdfs config upload 
```

Location

/usr/lpp/mmfs/hadoop/sbin