org.gridgain.grid.spi.checkpoint.sharedfs

Class GridSharedFsCheckpointSpi

java.lang.Object

org.gridgain.grid.spi.GridSpiAdapter

org.gridgain.grid.spi.checkpoint.sharedfs.GridSharedFsCheckpointSpi

All Implemented Interfaces:

GridCheckpointSpi, GridSharedFsCheckpointSpiMBean, GridSpi, GridSpiManagementMBean

@GridSpiMultipleInstancesSupport(value=true)
@GridSpiConsistencyChecked(optional=false)
public class GridSharedFsCheckpointSpi
extends GridSpiAdapter
implements GridCheckpointSpi, GridSharedFsCheckpointSpiMBean

This class defines shared file system GridCheckpointSpi implementation for checkpoint SPI. All checkpoints are stored on shared storage and available for all nodes in the grid. Note that every node must have access to the shared directory. The reason the directory needs to be shared is because a job state can be saved on one node and loaded on another (e.g. if a job gets preempted on a different node after node failure). When started, this SPI tracks all checkpoints saved by localhost for expiration. Note that this SPI does not cache data stored in checkpoints - all the data is loaded from file system on demand.

Directory paths for shared checkpoints should either be empty or contain previously stored checkpoint files.

Configuration

Mandatory

This SPI has no mandatory configuration parameters.

Optional

This SPI has following optional configuration parameters:

• Directory paths (see setDirectoryPaths(Collection))

Java Example

GridSharedFsCheckpointSpi can be configured as follows:

 GridConfiguration cfg = new GridConfiguration();

 GridSharedFsCheckpointSpi checkpointSpi = new GridSharedFsCheckpointSpi();

 // List of checkpoint directories where all files are stored.
 Collection dirPaths = new ArrayList();

 dirPaths.add("/my/directory/path");
 dirPaths.add("/other/directory/path");

 // Override default directory path.
 checkpointSpi.setDirectoryPaths(dirPaths);

 // Override default checkpoint SPI.
 cfg.setCheckpointSpi(checkpointSpi);

 // Starts grid.
 G.start(cfg);
 

Spring Example

GridSharedFsCheckpointSpi can be configured from Spring XML configuration file:

 <bean id="grid.custom.cfg" class="org.gridgain.grid.GridConfiguration" singleton="true">
     ...
     <property name="checkpointSpi">
         <bean class="org.gridgain.grid.spi.checkpoint.sharedfs.GridSharedFsCheckpointSpi">
             <!-- Change to shared directory path in your environment. -->
             <property name="directoryPaths">
                 <list>
                     <value>/my/directory/path</value>
                     <value>/other/directory/path</value>
                 </list>
             </property>
         </bean>
     </property>
     ...
 </bean>
 

For information about Spring framework visit www.springframework.org

See Also:

GridCheckpointSpi

Field Summary

Fields

Modifier and Type	Field and Description
static String	DFLT_DIR_PATH Default checkpoint directory.

Constructor Summary

Constructors

Constructor and Description
GridSharedFsCheckpointSpi() Initializes default directory paths.

Method Summary

Methods

Modifier and Type	Method and Description
String	getCurrentDirectoryPath() Gets path to the directory where all checkpoints are saved.
Collection<String>	getDirectoryPaths() Gets collection of all configured paths where checkpoints can be saved.
byte[]	loadCheckpoint(String key) Loads checkpoint from storage by its unique key.
boolean	removeCheckpoint(String key) This method instructs the checkpoint provider to clean saved data for a given key.
boolean	saveCheckpoint(String key, byte[] state, long timeout, boolean overwrite) Saves checkpoint to the storage.
void	setCheckpointListener(GridCheckpointListener lsnr) Sets the checkpoint listener.
void	setDirectoryPaths(Collection<String> dirPaths) Sets path to a shared directory where checkpoints will be stored.
void	spiStart(String gridName) This method is called to start SPI.
void	spiStop() This method is called to stop SPI.
String	toString()

Methods inherited from class org.gridgain.grid.spi.GridSpiAdapter

assertParameter, checkConfigurationConsistency0, configInfo, createSpiAttributeName, getConsistentAttributeNames, getGridGainHome, getLocalNodeId, getName, getNodeAttributes, getSpiContext, getStartTimestamp, getStartTimestampFormatted, getUpTime, getUpTimeFormatted, injectables, onContextDestroyed, onContextDestroyed0, onContextInitialized, onContextInitialized0, registerMBean, setName, startInfo, startStopwatch, stopInfo, unregisterMBean

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.gridgain.grid.spi.GridSpi

getName, getNodeAttributes, onContextDestroyed, onContextInitialized

Methods inherited from interface org.gridgain.grid.spi.GridSpiManagementMBean

getGridGainHome, getLocalNodeId, getName, getStartTimestamp, getStartTimestampFormatted, getUpTime, getUpTimeFormatted

Field Detail

DFLT_DIR_PATH

public static final String DFLT_DIR_PATH

Default checkpoint directory. Note that this path is relative to GRIDGAIN_HOME/work folder if GRIDGAIN_HOME system or environment variable specified, otherwise it is relative to work folder under system java.io.tmpdir folder.

See Also:

GridConfiguration.getWorkDirectory(), Constant Field Values

Constructor Detail

GridSharedFsCheckpointSpi

public GridSharedFsCheckpointSpi()

Initializes default directory paths.

Method Detail

getDirectoryPaths

public Collection<String> getDirectoryPaths()

Gets collection of all configured paths where checkpoints can be saved.

Specified by:

getDirectoryPaths in interface GridSharedFsCheckpointSpiMBean

Returns:

Collection of all configured paths.

getCurrentDirectoryPath

public String getCurrentDirectoryPath()

Gets path to the directory where all checkpoints are saved.

Specified by:

getCurrentDirectoryPath in interface GridSharedFsCheckpointSpiMBean

Returns:

Path to the checkpoints directory.

setDirectoryPaths

@GridSpiConfiguration(optional=true)
public void setDirectoryPaths(Collection<String> dirPaths)

Sets path to a shared directory where checkpoints will be stored. The path can either be absolute or relative to GRIDGAIN_HOME system or environment variable.

If not provided, default value is DFLT_DIR_PATH.

Parameters:

dirPaths - Absolute or GridGain installation home folder relative path where checkpoints will be stored.

spiStart

public void spiStart(String gridName)
              throws GridSpiException

This method is called to start SPI. After this method returns successfully kernel assumes that SPI is fully operational.

Specified by:

spiStart in interface GridSpi

Parameters:

gridName - Name of grid instance this SPI is being started for (null for default grid).

Throws:

GridSpiException - Throws in case of any error during SPI start.

spiStop

public void spiStop()
             throws GridSpiException

This method is called to stop SPI. After this method returns kernel assumes that this SPI is finished and all resources acquired by it are released.

Note that this method can be called at any point including during recovery of failed start. It should make no assumptions on what state SPI will be in when this method is called.

Specified by:

spiStop in interface GridSpi

Throws:

GridSpiException - Thrown in case of any error during SPI stop.

loadCheckpoint

public byte[] loadCheckpoint(String key)
                      throws GridSpiException

Loads checkpoint from storage by its unique key.

Specified by:

loadCheckpoint in interface GridCheckpointSpi

Parameters:

key - Checkpoint key.

Returns:

Loaded data or null if there is no data for a given key.

Throws:

GridSpiException - Thrown in case of any error while loading checkpoint data. Note that in case when given key is not found this method will return null.

saveCheckpoint

public boolean saveCheckpoint(String key,
                     byte[] state,
                     long timeout,
                     boolean overwrite)
                       throws GridSpiException

Saves checkpoint to the storage.

Specified by:

saveCheckpoint in interface GridCheckpointSpi

Parameters:

key - Checkpoint unique key.

state - Saved data.

timeout - Every intermediate data stored by checkpoint provider should have a timeout. Timeout allows for effective resource management by checkpoint provider by cleaning saved data that are not needed anymore. Generally, the user should choose the minimum possible timeout to avoid long-term resource acquisition by checkpoint provider. Value 0 means that timeout will never expire.

overwrite - Whether or not overwrite checkpoint if it already exists.

Returns:

true if checkpoint has been actually saved, false otherwise.

Throws:

GridSpiException - Thrown in case of any error while saving checkpoint data.

removeCheckpoint

public boolean removeCheckpoint(String key)

This method instructs the checkpoint provider to clean saved data for a given key.

Specified by:

removeCheckpoint in interface GridCheckpointSpi

Parameters:

key - Key for the checkpoint to remove.

Returns:

true if data has been actually removed, false otherwise.

setCheckpointListener

public void setCheckpointListener(GridCheckpointListener lsnr)

Sets the checkpoint listener.

Specified by:

setCheckpointListener in interface GridCheckpointSpi

Parameters:

lsnr - The listener to set or null.

toString

public String toString()

Overrides:

toString in class Object