DiskBalancerCLI (Apache Hadoop HDFS 3.4.1.200-dep-1000 API)

java.lang.Object
- org.apache.hadoop.conf.Configured
- - org.apache.hadoop.hdfs.tools.DiskBalancerCLI

All Implemented Interfaces:

org.apache.hadoop.conf.Configurable, org.apache.hadoop.util.Tool
```
public class DiskBalancerCLI
extends org.apache.hadoop.conf.Configured
implements org.apache.hadoop.util.Tool
```
DiskBalancer is a tool that can be used to ensure that data is spread evenly across volumes of same storage type.
For example, if you have 3 disks, with 100 GB , 600 GB and 200 GB on each disk, this tool will ensure that each disk will have 300 GB.
This tool can be run while data nodes are fully functional.
At very high level diskbalancer computes a set of moves that will make disk utilization equal and then those moves are executed by the datanode.

Field Summary

Fields
Modifier and Type	Field	Description
`static java.lang.String`	`BANDWIDTH`	Specifies the maximum disk bandwidth to use per second.
`static java.lang.String`	`BEFORE_TEMPLATE`	Template for the Before File.
`static java.lang.String`	`CANCEL`	Cancels a running plan.
`static int`	`DEFAULT_TOP`	specify default top number of nodes to be processed.
`static java.lang.String`	`EXECUTE`	Executes a given plan file on the target datanode.
`static java.lang.String`	`HELP`	Help for the program.
`static java.lang.String`	`MAXERROR`	Specifies the maximum errors to tolerate.
`static java.lang.String`	`NODE`	Name or address of the node to execute against.
`static java.lang.String`	`OUTFILE`	Output file name, for commands like report, plan etc.
`static java.lang.String`	`PLAN`	Computes a plan for a given set of nodes.
`static java.lang.String`	`PLAN_TEMPLATE`	Template for the plan file.
`static int`	`PLAN_VERSION`
`static java.lang.String`	`QUERY`	Reports the status of disk balancer operation.
`static java.lang.String`	`REPORT`	The report command prints out a disk fragmentation report about the data cluster.
`static java.lang.String`	`SKIPDATECHECK`	Skips date check(now by default the plan is valid for 24 hours), and force execute the plan.
`static java.lang.String`	`THRESHOLD`	Percentage of data unevenness that we are willing to live with.
`static java.lang.String`	`TOP`	specify top number of nodes to be processed.
`static java.lang.String`	`VERBOSE`	Runs the command in verbose mode.

Constructor Summary

Constructors
Constructor	Description
`DiskBalancerCLI(org.apache.hadoop.conf.Configuration conf)`	Construct a DiskBalancer.
`DiskBalancerCLI(org.apache.hadoop.conf.Configuration conf, java.io.PrintStream printStream)`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`static org.apache.commons.cli.Options`	`getCancelOptions()`	Returns Cancel Options.
`Command`	`getCurrentCommand()`	Gets current command associated with this instance of DiskBalancer.
`static org.apache.commons.cli.Options`	`getExecuteOptions()`	Retuns execute options.
`static org.apache.commons.cli.Options`	`getHelpOptions()`	Returns help options.
`static org.apache.commons.cli.Options`	`getPlanOptions()`	Returns Plan options.
`static org.apache.commons.cli.Options`	`getQueryOptions()`	Returns Query Options.
`static org.apache.commons.cli.Options`	`getReportOptions()`	Returns Report Options.
`static void`	`main(java.lang.String[] argv)`	Main for the DiskBalancer Command handling.
`int`	`run(java.lang.String[] args)`	Execute the command with the given arguments.

Methods inherited from class org.apache.hadoop.conf.Configured
getConf, setConf

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.hadoop.conf.Configurable
getConf, setConf

- Field Detail
  - PLAN
```
public static final java.lang.String PLAN
```
    Computes a plan for a given set of nodes.
    
    See Also:
    
    Constant Field Values
  - OUTFILE
```
public static final java.lang.String OUTFILE
```
    Output file name, for commands like report, plan etc. This is an optional argument, by default diskbalancer will write all its output to /system/reports/diskbalancer of the current cluster it is operating against.
    
    See Also:
    
    Constant Field Values
  - HELP
```
public static final java.lang.String HELP
```
    Help for the program.
    
    See Also:
    
    Constant Field Values
  - THRESHOLD
```
public static final java.lang.String THRESHOLD
```
    Percentage of data unevenness that we are willing to live with. For example - a value like 10 indicates that we are okay with 10 % +/- from idealStorage Target.
    
    See Also:
    
    Constant Field Values
  - BANDWIDTH
```
public static final java.lang.String BANDWIDTH
```
    Specifies the maximum disk bandwidth to use per second.
    
    See Also:
    
    Constant Field Values
  - MAXERROR
```
public static final java.lang.String MAXERROR
```
    Specifies the maximum errors to tolerate.
    
    See Also:
    
    Constant Field Values
  - EXECUTE
```
public static final java.lang.String EXECUTE
```
    Executes a given plan file on the target datanode.
    
    See Also:
    
    Constant Field Values
  - SKIPDATECHECK
```
public static final java.lang.String SKIPDATECHECK
```
    Skips date check(now by default the plan is valid for 24 hours), and force execute the plan.
    
    See Also:
    
    Constant Field Values
  - REPORT
```
public static final java.lang.String REPORT
```
    The report command prints out a disk fragmentation report about the data cluster. By default it prints the DEFAULT_TOP machines names with high nodeDataDensity {DiskBalancerDataNode#getNodeDataDensity} values. This means that these are the nodes that deviates from the ideal data distribution.
    
    See Also:
    
    Constant Field Values
  - TOP
```
public static final java.lang.String TOP
```
    specify top number of nodes to be processed.
    
    See Also:
    
    Constant Field Values
  - DEFAULT_TOP
```
public static final int DEFAULT_TOP
```
    specify default top number of nodes to be processed.
    
    See Also:
    
    Constant Field Values
  - NODE
```
public static final java.lang.String NODE
```
    Name or address of the node to execute against.
    
    See Also:
    
    Constant Field Values
  - VERBOSE
```
public static final java.lang.String VERBOSE
```
    Runs the command in verbose mode.
    
    See Also:
    
    Constant Field Values
  - PLAN_VERSION
```
public static final int PLAN_VERSION
```
    See Also:
    
    Constant Field Values
  - QUERY
```
public static final java.lang.String QUERY
```
    Reports the status of disk balancer operation.
    
    See Also:
    
    Constant Field Values
  - CANCEL
```
public static final java.lang.String CANCEL
```
    Cancels a running plan.
    
    See Also:
    
    Constant Field Values
  - BEFORE_TEMPLATE
```
public static final java.lang.String BEFORE_TEMPLATE
```
    Template for the Before File. It is node.before.json.
    
    See Also:
    
    Constant Field Values
  - PLAN_TEMPLATE
```
public static final java.lang.String PLAN_TEMPLATE
```
    Template for the plan file. it is node.plan.json.
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - DiskBalancerCLI
```
public DiskBalancerCLI(org.apache.hadoop.conf.Configuration conf)
```
    Construct a DiskBalancer.
    
    Parameters:
    
    conf -
  - DiskBalancerCLI
```
public DiskBalancerCLI(org.apache.hadoop.conf.Configuration conf,
                       java.io.PrintStream printStream)
```
- Method Detail
  - main
```
public static void main(java.lang.String[] argv)
                 throws java.lang.Exception
```
    Main for the DiskBalancer Command handling.
    
    Parameters:
    
    argv - - System Args Strings[]
    
    Throws:
    
    java.lang.Exception
  - run
```
public int run(java.lang.String[] args)
        throws java.lang.Exception
```
    Execute the command with the given arguments.
    
    Specified by:
    
    run in interface org.apache.hadoop.util.Tool
    
    Parameters:
    
    args - command specific arguments.
    
    Returns:
    
    exit code.
    
    Throws:
    
    java.lang.Exception
  - getPlanOptions
```
public static org.apache.commons.cli.Options getPlanOptions()
```
    Returns Plan options.
    
    Returns:
    
    Options.
  - getHelpOptions
```
public static org.apache.commons.cli.Options getHelpOptions()
```
    Returns help options.
    
    Returns:
    
    - help options.
  - getExecuteOptions
```
public static org.apache.commons.cli.Options getExecuteOptions()
```
    Retuns execute options.
    
    Returns:
    
    - execute options.
  - getQueryOptions
```
public static org.apache.commons.cli.Options getQueryOptions()
```
    Returns Query Options.
    
    Returns:
    
    query Options
  - getCancelOptions
```
public static org.apache.commons.cli.Options getCancelOptions()
```
    Returns Cancel Options.
    
    Returns:
    
    Options
  - getReportOptions
```
public static org.apache.commons.cli.Options getReportOptions()
```
    Returns Report Options.
    
    Returns:
    
    Options
  - getCurrentCommand
```
public Command getCurrentCommand()
```
    Gets current command associated with this instance of DiskBalancer.

Class DiskBalancerCLI

Field Summary

Constructor Summary

Method Summary

Methods inherited from class org.apache.hadoop.conf.Configured

Methods inherited from class java.lang.Object

Methods inherited from interface org.apache.hadoop.conf.Configurable

Field Detail

PLAN

OUTFILE

HELP

THRESHOLD

BANDWIDTH

MAXERROR

EXECUTE

SKIPDATECHECK

REPORT

TOP

DEFAULT_TOP

NODE

VERBOSE

PLAN_VERSION

QUERY

CANCEL

BEFORE_TEMPLATE

PLAN_TEMPLATE

Constructor Detail

DiskBalancerCLI

DiskBalancerCLI

Method Detail

main

run

getPlanOptions

getHelpOptions

getExecuteOptions

getQueryOptions

getCancelOptions

getReportOptions

getCurrentCommand