ClusterMetrics (Apache HBase 2.5.0 API)

All Known Implementing Classes:

ClusterMetricsBuilder.ClusterMetricsImpl, ClusterStatus
```
@InterfaceAudience.Public
public interface ClusterMetrics
```
Metrics information on the HBase cluster.
ClusterMetrics provides clients with information such as:
- The count and names of region servers in the cluster.
- The count and names of dead region servers in the cluster.
- The name of the active master for the cluster.
- The name(s) of the backup master(s) for the cluster, if they exist.
- The average cluster load.
- The number of regions deployed on the cluster.
- The number of requests since last report.
- Detailed region server loading and resource usage information, per server and per region.
- Regions in transition at master
- The unique cluster ID
ClusterMetrics.Option provides a way to get desired ClusterStatus information. The following codes will get all the cluster information.
```
 {
   @code
   // Original version still works
   Admin admin = connection.getAdmin();
   ClusterMetrics metrics = admin.getClusterStatus();
   // or below, a new version which has the same effects
   ClusterMetrics metrics = admin.getClusterStatus(EnumSet.allOf(Option.class));
 }
 
```
If information about live servers is the only wanted. then codes in the following way:
```
 {
   @code
   Admin admin = connection.getAdmin();
   ClusterMetrics metrics = admin.getClusterStatus(EnumSet.of(Option.LIVE_SERVERS));
 }
 
```

Nested Class Summary

Nested Classes
Modifier and Type Interface and Description

static class ClusterMetrics.Option
Kinds of ClusterMetrics

Nested Classes
Modifier and Type	Interface and Description
`static class`	`ClusterMetrics.Option` Kinds of ClusterMetrics

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method and Description
`default double`	`getAverageLoad()` Returns the average cluster load
`List<ServerName>`	`getBackupMasterNames()` Returns the names of backup masters
`Boolean`	`getBalancerOn()`
`String`	`getClusterId()`
`List<ServerName>`	`getDeadServerNames()` Returns the names of region servers on the dead list
`String`	`getHBaseVersion()` Returns the HBase version string as reported by the HMaster
`default long`	`getLastMajorCompactionTimestamp(byte[] regionName)`
`default long`	`getLastMajorCompactionTimestamp(TableName table)`
`Map<ServerName,ServerMetrics>`	`getLiveServerMetrics()` Returns the names of region servers on the live list
`List<String>`	`getMasterCoprocessorNames()`
`int`	`getMasterInfoPort()`
`ServerName`	`getMasterName()` Returns detailed information about the current master `ServerName`.
`List<ServerTask>`	`getMasterTasks()` Provide the list of master tasks
`default int`	`getRegionCount()` Returns the number of regions deployed on the cluster
`List<RegionState>`	`getRegionStatesInTransition()`
`default long`	`getRequestCount()` Returns the number of requests since last report
`List<ServerName>`	`getServersName()`
`Map<TableName,RegionStatesCount>`	`getTableRegionStatesCount()` Provide region states count for given table.
`List<ServerName>`	`getUnknownServerNames()` Returns the names of region servers on the unknown list

- Method Detail
  - getHBaseVersion
```
@Nullable
String getHBaseVersion()
```
    Returns the HBase version string as reported by the HMaster
  - getDeadServerNames
```
List<ServerName> getDeadServerNames()
```
    Returns the names of region servers on the dead list
  - getUnknownServerNames
```
List<ServerName> getUnknownServerNames()
```
    Returns the names of region servers on the unknown list
  - getLiveServerMetrics
```
Map<ServerName,ServerMetrics> getLiveServerMetrics()
```
    Returns the names of region servers on the live list
  - getRegionCount
```
default int getRegionCount()
```
    Returns the number of regions deployed on the cluster
  - getRequestCount
```
default long getRequestCount()
```
    Returns the number of requests since last report
  - getMasterName
```
@Nullable
ServerName getMasterName()
```
    Returns detailed information about the current master ServerName.
    
    Returns:
    
    current master information if it exists
  - getBackupMasterNames
```
List<ServerName> getBackupMasterNames()
```
    Returns the names of backup masters
  - getRegionStatesInTransition
```
@InterfaceAudience.Private
List<RegionState> getRegionStatesInTransition()
```
  - getClusterId
```
@Nullable
String getClusterId()
```
  - getMasterCoprocessorNames
```
List<String> getMasterCoprocessorNames()
```
  - getLastMajorCompactionTimestamp
```
default long getLastMajorCompactionTimestamp(TableName table)
```
  - getLastMajorCompactionTimestamp
```
default long getLastMajorCompactionTimestamp(byte[] regionName)
```
  - getBalancerOn
```
@Nullable
Boolean getBalancerOn()
```
  - getMasterInfoPort
```
int getMasterInfoPort()
```
  - getServersName
```
List<ServerName> getServersName()
```
  - getAverageLoad
```
default double getAverageLoad()
```
    Returns the average cluster load
  - getTableRegionStatesCount
```
Map<TableName,RegionStatesCount> getTableRegionStatesCount()
```
    Provide region states count for given table. e.g howmany regions of give table are opened/closed/rit etc
    
    Returns:
    
    map of table to region states count
  - getMasterTasks
```
@Nullable
List<ServerTask> getMasterTasks()
```
    Provide the list of master tasks

Interface ClusterMetrics

Nested Class Summary

Method Summary

Method Detail

getHBaseVersion

getDeadServerNames

getUnknownServerNames

getLiveServerMetrics

getRegionCount

getRequestCount

getMasterName

getBackupMasterNames

getRegionStatesInTransition

getClusterId

getMasterCoprocessorNames

getLastMajorCompactionTimestamp

getLastMajorCompactionTimestamp

getBalancerOn

getMasterInfoPort

getServersName

getAverageLoad

getTableRegionStatesCount

getMasterTasks