HighAvailabilityManager (Apache Brooklyn)

All Known Implementing Classes:

HighAvailabilityManagerImpl
```
@Beta
public interface HighAvailabilityManager
```
Monitors other management nodes (via the ManagementPlaneSyncRecordPersister) to detect if the current master has failed or stopped. If so, then deterministically chooses a new master. If that master is self, then promotes. Users are not expected to implement this class, or to call methods on it directly. Expected lifecycle of methods calls on this is:
1. setPersister(ManagementPlaneSyncRecordPersister)
2. Exactly one of disabled() or start(HighAvailabilityMode)
3. stop()
Since:

0.7.0

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`changeMode(HighAvailabilityMode mode)` changes the mode that this HA server is running in
`void`	`disabled()` Indicates that HA is disabled: this node will act as the only management node in this management plane, and will not persist HA meta-information (meaning other nodes cannot join).
`ManagementPlaneSyncRecord`	`getManagementPlaneSyncState()` Returns a snapshot of the management-plane's current / most-recently-known status.
`ManagementNodeState`	`getNodeState()`
`ManagementPlaneSyncRecordPersister`	`getPersister()`
`long`	`getPriority()`
`boolean`	`isRunning()` Whether HA mode is operational
`HighAvailabilityManager`	`setPersister(ManagementPlaneSyncRecordPersister persister)`
`void`	`setPriority(long priority)` sets the priority, and publishes it synchronously so it is canonical
`void`	`start(HighAvailabilityMode startMode)` Starts the monitoring of other nodes (and thus potential promotion of this node from standby to master).
`void`	`stop()` Stops this node, then publishes own status (via `ManagementPlaneSyncRecordPersister` of `ManagementNodeState.TERMINATED`.

- Method Detail
  - getNodeState
```
ManagementNodeState getNodeState()
```
  - setPersister
```
HighAvailabilityManager setPersister(ManagementPlaneSyncRecordPersister persister)
```
    Parameters:
    persister -
    
    Returns:
    self
  - disabled
```
@Beta
void disabled()
```
    Indicates that HA is disabled: this node will act as the only management node in this management plane, and will not persist HA meta-information (meaning other nodes cannot join).
    Subsequently can expect getNodeState() to be ManagementNodeState.MASTER and getManagementPlaneSyncState() to show just this one node -- as if it were running HA with just one node -- but isRunning() will return false.
    Currently this method is intended to be called early in the lifecycle, instead of start(HighAvailabilityMode). It may be an error if this is called after this HA Manager is started.
  - isRunning
```
boolean isRunning()
```
    Whether HA mode is operational
  - start
```
void start(HighAvailabilityMode startMode)
```
    Starts the monitoring of other nodes (and thus potential promotion of this node from standby to master).
    When this method returns, the status of this node will be set, either ManagementNodeState.MASTER if appropriate or ManagementNodeState.STANDBY / ManagementNodeState.HOT_STANDBY.
    
    Parameters:
    startMode - mode to start with
    
    Throws:
    
    java.lang.IllegalStateException - if current state of the management-plane doesn't match that desired by startMode
  - stop
```
void stop()
```
    Stops this node, then publishes own status (via ManagementPlaneSyncRecordPersister of ManagementNodeState.TERMINATED.
  - changeMode
```
void changeMode(HighAvailabilityMode mode)
```
    changes the mode that this HA server is running in
    note it will be an error to changeMode(HighAvailabilityMode) to ManagementNodeState.MASTER when there is already a master; to promote a node explicitly set its priority higher than the others and invoke changeMode(HighAvailabilityMode) to a standby mode on the existing master
  - setPriority
```
void setPriority(long priority)
```
    sets the priority, and publishes it synchronously so it is canonical
  - getPriority
```
long getPriority()
```
  - getManagementPlaneSyncState
```
ManagementPlaneSyncRecord getManagementPlaneSyncState()
```
    Returns a snapshot of the management-plane's current / most-recently-known status.
    This is mainly the nodes and their ManagementNodeSyncRecord instances, as known (for this node) or last read (other nodes).
  - getPersister
```
ManagementPlaneSyncRecordPersister getPersister()
```

Interface HighAvailabilityManager

Method Summary

Method Detail

getNodeState

setPersister

disabled

isRunning

start

stop

changeMode

setPriority

getPriority

getManagementPlaneSyncState

getPersister