org.apache.ignite.spi.checkpoint.sharedfs

Class SharedFsCheckpointSpi

java.lang.Object

org.apache.ignite.spi.IgniteSpiAdapter

org.apache.ignite.spi.checkpoint.sharedfs.SharedFsCheckpointSpi

All Implemented Interfaces:

CheckpointSpi, IgniteSpi

@IgniteSpiMultipleInstancesSupport(value=true)
 @IgniteSpiConsistencyChecked(optional=false)
public class SharedFsCheckpointSpi
extends IgniteSpiAdapter
implements CheckpointSpi

This class defines shared file system CheckpointSpi 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

SharedFsCheckpointSpi can be configured as follows:

 IgniteConfiguration cfg = new IgniteConfiguration();

 SharedFsCheckpointSpi checkpointSpi = new SharedFsCheckpointSpi();

 // 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

SharedFsCheckpointSpi can be configured from Spring XML configuration file:

 <bean id="grid.custom.cfg" class="org.apache.ignite.configuration.IgniteConfiguration" singleton="true">
     ...
     <property name="checkpointSpi">
         <bean class="org.apache.ignite.spi.checkpoint.sharedfs.SharedFsCheckpointSpi">
             <!-- 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:

CheckpointSpi

Field Summary

Fields

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

Constructor Summary

Constructors

Constructor and Description
SharedFsCheckpointSpi() Initializes default directory paths.

Method Summary

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(CheckpointListener lsnr) Sets the checkpoint listener.
SharedFsCheckpointSpi	setDirectoryPaths(Collection<String> dirPaths) Sets path to a shared directory where checkpoints will be stored.
SharedFsCheckpointSpi	setName(String name) Sets SPI name.
void	spiStart(String igniteInstanceName) This method is called to start SPI.
void	spiStop() This method is called to stop SPI.
String	toString()

Methods inherited from class org.apache.ignite.spi.IgniteSpiAdapter

addTimeoutObject, assertParameter, checkConfigurationConsistency0, clientFailureDetectionTimeout, configInfo, createSpiAttributeName, failureDetectionTimeout, failureDetectionTimeoutEnabled, failureDetectionTimeoutEnabled, getConsistentAttributeNames, getExceptionRegistry, getLocalNode, getName, getNodeAttributes, getSpiContext, ignite, initFailureDetectionTimeout, injectables, injectResources, isNodeStopping, onBeforeStart, onClientDisconnected, onClientReconnected, onContextDestroyed, onContextDestroyed0, onContextInitialized, onContextInitialized0, registerMBean, removeTimeoutObject, started, 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.apache.ignite.spi.IgniteSpi

getName, getNodeAttributes, onClientDisconnected, onClientReconnected, onContextDestroyed, onContextInitialized

Field Detail

DFLT_DIR_PATH

public static final String DFLT_DIR_PATH

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

See Also:

IgniteConfiguration.getWorkDirectory(), Constant Field Values

Constructor Detail

SharedFsCheckpointSpi

public SharedFsCheckpointSpi()

Initializes default directory paths.

Method Detail

getDirectoryPaths

public Collection<String> getDirectoryPaths()

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

Returns:

Collection of all configured paths.

getCurrentDirectoryPath

public String getCurrentDirectoryPath()

Gets path to the directory where all checkpoints are saved.

Returns:

Path to the checkpoints directory.

setDirectoryPaths

@IgniteSpiConfiguration(optional=true)
public SharedFsCheckpointSpi setDirectoryPaths(Collection<String> dirPaths)

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

If not provided, default value is DFLT_DIR_PATH.

Parameters:

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

Returns:

this for chaining.

spiStart

public void spiStart(String igniteInstanceName)
              throws IgniteSpiException

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

Specified by:

spiStart in interface IgniteSpi

Parameters:

igniteInstanceName - Name of Ignite instance this SPI is being started for (null for default Ignite instance).

Throws:

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

spiStop

public void spiStop()
             throws IgniteSpiException

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 IgniteSpi

Throws:

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

loadCheckpoint

public byte[] loadCheckpoint(String key)
                      throws IgniteSpiException

Loads checkpoint from storage by its unique key.

Specified by:

loadCheckpoint in interface CheckpointSpi

Parameters:

key - Checkpoint key.

Returns:

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

Throws:

IgniteSpiException - 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 IgniteSpiException

Saves checkpoint to the storage.

Specified by:

saveCheckpoint in interface CheckpointSpi

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:

IgniteSpiException - 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 CheckpointSpi

Parameters:

key - Key for the checkpoint to remove.

Returns:

true if data has been actually removed, false otherwise.

setCheckpointListener

public void setCheckpointListener(CheckpointListener lsnr)

Sets the checkpoint listener.

Specified by:

setCheckpointListener in interface CheckpointSpi

Parameters:

lsnr - The listener to set or null.

setName

public SharedFsCheckpointSpi setName(String name)

Sets SPI name.

Overrides:

setName in class IgniteSpiAdapter

Parameters:

name - SPI name.

Returns:

this for chaining.

toString

public String toString()

Overrides:

toString in class Object