HighAvailabilityManagerImpl (Apache Brooklyn)

java.lang.Object
- brooklyn.management.ha.HighAvailabilityManagerImpl

All Implemented Interfaces:

HighAvailabilityManager
```
@Beta
public class HighAvailabilityManagerImpl
extends java.lang.Object
implements HighAvailabilityManager
```
This is the guts of the high-availability solution in Brooklyn.
Multiple brooklyn nodes can be started to form a single management plane, where one node is designated master and the others are "warm standbys". On termination or failure of the master, the standbys deterministically decide which standby should become master (see MasterChooser). That standby promotes itself.
The management nodes communicate their health/status via the ManagementPlaneSyncRecordPersister. For example, if using ManagementPlaneSyncRecordPersisterToObjectStore with a shared blobstore or filesystem/NFS mount, then each management-node periodically writes its state. This acts as a heartbeat, being read by the other management-nodes.
Promotion to master involves:
1. notifying the other management-nodes that it is now master
2. calling RebindManager.rebind(ClassLoader, brooklyn.entity.rebind.RebindExceptionHandler, ManagementNodeState) to read all persisted entity state, and thus reconstitute the entities.
Future improvements in this area will include brooklyn-managing-brooklyn to decide + promote the standby.
Since:

0.7.0

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static interface HighAvailabilityManagerImpl.PromotionListener

Nested Classes
Modifier and Type	Class and Description
`static interface`	`HighAvailabilityManagerImpl.PromotionListener`

Field Summary

Fields
Modifier and Type Field and Description

ConfigKey<Duration> HEARTBEAT_TIMEOUT

ConfigKey<Duration> POLL_PERIOD

Fields
Modifier and Type	Field and Description
`ConfigKey<Duration>`	`HEARTBEAT_TIMEOUT`
`ConfigKey<Duration>`	`POLL_PERIOD`

Constructor Summary

Constructors
Constructor and Description

HighAvailabilityManagerImpl(ManagementContextInternal managementContext)

Constructors
Constructor and Description
`HighAvailabilityManagerImpl(ManagementContextInternal managementContext)`

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`changeMode(HighAvailabilityMode startMode)` changes the mode that this HA server is running in
`void`	`changeMode(HighAvailabilityMode startMode, boolean preventElectionOnExplicitStandbyMode, boolean failOnExplicitModesIfUnusual)`
`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).
`Duration`	`getHeartbeatTimeout()`
`ManagementPlaneSyncRecord`	`getLastManagementPlaneSyncRecord()` Returns a snapshot of the management-plane's current / most-recently-known status, as last read from `HighAvailabilityManager.loadManagementPlaneSyncRecord(boolean)`, or null if none read.
`long`	`getLastStateChange()` The time in milliseconds when the state was last changed.
`ManagementPlaneSyncRecord`	`getManagementPlaneSyncState()`
`java.util.Map<java.lang.String,java.lang.Object>`	`getMetrics()` Returns a collection of metrics
`ManagementNodeState`	`getNodeState()`
`ManagementPlaneSyncRecordPersister`	`getPersister()`
`long`	`getPriority()`
`ManagementNodeState`	`getTransitionTargetNodeState()` returns the node state this node is trying to be in
`boolean`	`isRunning()` Whether HA mode is operational
`ManagementPlaneSyncRecord`	`loadManagementPlaneSyncRecord(boolean useLocalKnowledgeForThisNode)`
`void`	`publishAndCheck(boolean initializing)` invoked manually when initializing, and periodically thereafter
`void`	`publishClearNonMaster()` deletes non-master node records; active nodes (including this) will republish, so this provides a simple way to clean out the cache of dead brooklyn nodes
`HighAvailabilityManagerImpl`	`setHeartbeatTimeout(Duration val)` Overrides `HEARTBEAT_TIMEOUT` from brooklyn config, including e.g.
`HighAvailabilityManagerImpl`	`setLocalTicker(com.google.common.base.Ticker val)` A ticker that reads in milliseconds, for populating local timestamps.
`HighAvailabilityManagerImpl`	`setMasterChooser(MasterChooser val)`
`HighAvailabilityManagerImpl`	`setPersister(ManagementPlaneSyncRecordPersister persister)`
`HighAvailabilityManagerImpl`	`setPollPeriod(Duration val)` Overrides `POLL_PERIOD` from brooklyn config, including e.g.
`void`	`setPriority(long priority)` sets the priority, and publishes it synchronously so it is canonical
`HighAvailabilityManagerImpl`	`setPromotionListener(HighAvailabilityManagerImpl.PromotionListener val)`
`HighAvailabilityManagerImpl`	`setRemoteTicker(com.google.common.base.Ticker val)` A ticker that reads in milliseconds, for overriding remote timestamps.
`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`.
`java.lang.String`	`toString()`

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

- Field Detail
  - POLL_PERIOD
```
public final ConfigKey<Duration> POLL_PERIOD
```
  - HEARTBEAT_TIMEOUT
```
public final ConfigKey<Duration> HEARTBEAT_TIMEOUT
```
- Constructor Detail
  - HighAvailabilityManagerImpl
```
public HighAvailabilityManagerImpl(ManagementContextInternal managementContext)
```
- Method Detail
  - setPersister
```
public HighAvailabilityManagerImpl setPersister(ManagementPlaneSyncRecordPersister persister)
```
    Specified by:
    
    setPersister in interface HighAvailabilityManager
    
    Returns:
    self
  - getPersister
```
public ManagementPlaneSyncRecordPersister getPersister()
```
    Specified by:
    
    getPersister in interface HighAvailabilityManager
  - setPollPeriod
```
public HighAvailabilityManagerImpl setPollPeriod(Duration val)
```
    Overrides POLL_PERIOD from brooklyn config, including e.g. Duration.PRACTICALLY_FOREVER to disable polling; or null to clear a local override
  - setMasterChooser
```
public HighAvailabilityManagerImpl setMasterChooser(MasterChooser val)
```
  - getHeartbeatTimeout
```
public Duration getHeartbeatTimeout()
```
  - setHeartbeatTimeout
```
public HighAvailabilityManagerImpl setHeartbeatTimeout(Duration val)
```
    Overrides HEARTBEAT_TIMEOUT from brooklyn config, including e.g. Duration.PRACTICALLY_FOREVER to prevent failover due to heartbeat absence; or null to clear a local override
  - setLocalTicker
```
public HighAvailabilityManagerImpl setLocalTicker(com.google.common.base.Ticker val)
```
    A ticker that reads in milliseconds, for populating local timestamps. Defaults to System.currentTimeMillis(); may be overridden e.g. for testing.
  - setRemoteTicker
```
public HighAvailabilityManagerImpl setRemoteTicker(com.google.common.base.Ticker val)
```
    A ticker that reads in milliseconds, for overriding remote timestamps. Defaults to null which means to use the remote timestamp. Only for testing as this records the remote timestamp in the object.
    If this is supplied, one must also set ManagementPlaneSyncRecordPersisterToObjectStore#useRemoteTimestampInMemento().
  - setPromotionListener
```
public HighAvailabilityManagerImpl setPromotionListener(HighAvailabilityManagerImpl.PromotionListener val)
```
  - isRunning
```
public boolean isRunning()
```
    Description copied from interface: HighAvailabilityManager
    
    Whether HA mode is operational
    
    Specified by:
    
    isRunning in interface HighAvailabilityManager
  - disabled
```
public void disabled()
```
    Description copied from interface: HighAvailabilityManager
    
    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 HighAvailabilityManager.getNodeState() to be ManagementNodeState.MASTER and HighAvailabilityManager.loadManagementPlaneSyncRecord(boolean) to show just this one node -- as if it were running HA with just one node -- but HighAvailabilityManager.isRunning() will return false.
    Currently this method is intended to be called early in the lifecycle, instead of HighAvailabilityManager.start(HighAvailabilityMode). It may be an error if this is called after this HA Manager is started.
    
    Specified by:
    
    disabled in interface HighAvailabilityManager
  - start
```
public void start(HighAvailabilityMode startMode)
```
    Description copied from interface: HighAvailabilityManager
    
    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 / ManagementNodeState.HOT_BACKUP.
    
    Specified by:
    
    start in interface HighAvailabilityManager
    
    Parameters:
    startMode - mode to start with
  - changeMode
```
public void changeMode(HighAvailabilityMode startMode)
```
    Description copied from interface: HighAvailabilityManager
    
    changes the mode that this HA server is running in
    note it will be an error to HighAvailabilityManager.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 HighAvailabilityManager.changeMode(HighAvailabilityMode) to a standby mode on the existing master
    
    Specified by:
    
    changeMode in interface HighAvailabilityManager
  - changeMode
```
@Beta
public void changeMode(HighAvailabilityMode startMode,
                   boolean preventElectionOnExplicitStandbyMode,
                   boolean failOnExplicitModesIfUnusual)
```
  - setPriority
```
public void setPriority(long priority)
```
    Description copied from interface: HighAvailabilityManager
    
    sets the priority, and publishes it synchronously so it is canonical
    
    Specified by:
    
    setPriority in interface HighAvailabilityManager
  - getPriority
```
public long getPriority()
```
    Specified by:
    
    getPriority in interface HighAvailabilityManager
  - stop
```
public void stop()
```
    Description copied from interface: HighAvailabilityManager
    
    Stops this node, then publishes own status (via ManagementPlaneSyncRecordPersister of ManagementNodeState.TERMINATED.
    
    Specified by:
    
    stop in interface HighAvailabilityManager
  - getTransitionTargetNodeState
```
public ManagementNodeState getTransitionTargetNodeState()
```
    returns the node state this node is trying to be in
  - getNodeState
```
public ManagementNodeState getNodeState()
```
    Specified by:
    
    getNodeState in interface HighAvailabilityManager
  - getLastManagementPlaneSyncRecord
```
public ManagementPlaneSyncRecord getLastManagementPlaneSyncRecord()
```
    Description copied from interface: HighAvailabilityManager
    
    Returns a snapshot of the management-plane's current / most-recently-known status, as last read from HighAvailabilityManager.loadManagementPlaneSyncRecord(boolean), or null if none read.
    
    Specified by:
    
    getLastManagementPlaneSyncRecord in interface HighAvailabilityManager
  - getManagementPlaneSyncState
```
public ManagementPlaneSyncRecord getManagementPlaneSyncState()
```
    Specified by:
    
    getManagementPlaneSyncState in interface HighAvailabilityManager
  - publishAndCheck
```
public void publishAndCheck(boolean initializing)
```
    invoked manually when initializing, and periodically thereafter
  - publishClearNonMaster
```
public void publishClearNonMaster()
```
    Description copied from interface: HighAvailabilityManager
    
    deletes non-master node records; active nodes (including this) will republish, so this provides a simple way to clean out the cache of dead brooklyn nodes
    
    Specified by:
    
    publishClearNonMaster in interface HighAvailabilityManager
  - loadManagementPlaneSyncRecord
```
public ManagementPlaneSyncRecord loadManagementPlaneSyncRecord(boolean useLocalKnowledgeForThisNode)
```
    Specified by:
    
    loadManagementPlaneSyncRecord in interface HighAvailabilityManager
    
    Parameters:
    useLocalKnowledgeForThisNode - - if true, the record for this mgmt node will be replaced with the actual current status known in this JVM (may be more recent than what is persisted); for most purposes there is little difference but in some cases the local node being updated may be explicitly wanted or not wanted
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object
  - getMetrics
```
public java.util.Map<java.lang.String,java.lang.Object> getMetrics()
```
    Description copied from interface: HighAvailabilityManager
    
    Returns a collection of metrics
    
    Specified by:
    
    getMetrics in interface HighAvailabilityManager
  - getLastStateChange
```
public long getLastStateChange()
```
    Description copied from interface: HighAvailabilityManager
    
    The time in milliseconds when the state was last changed. -1 if no state transition has occurred yet.
    
    Specified by:
    
    getLastStateChange in interface HighAvailabilityManager

Class HighAvailabilityManagerImpl

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

POLL_PERIOD

HEARTBEAT_TIMEOUT

Constructor Detail

HighAvailabilityManagerImpl

Method Detail

setPersister

getPersister

setPollPeriod

setMasterChooser

getHeartbeatTimeout

setHeartbeatTimeout

setLocalTicker

setRemoteTicker

setPromotionListener

isRunning

disabled

start

changeMode

changeMode

setPriority

getPriority

stop

getTransitionTargetNodeState

getNodeState

getLastManagementPlaneSyncRecord

getManagementPlaneSyncState

publishAndCheck

publishClearNonMaster

loadManagementPlaneSyncRecord

toString

getMetrics

getLastStateChange