org.apache.hadoop.ha
Class HAServiceTarget

java.lang.Object
  org.apache.hadoop.ha.HAServiceTarget

@InterfaceAudience.Public
@InterfaceStability.Evolving
public abstract class HAServiceTarget
extends Object

Represents a target of the client side HA administration commands.

Constructor Summary

HAServiceTarget()

Method Summary

protected void	addFencingParameters(Map<String,String> ret) Hook to allow subclasses to add any parameters they would like to expose to fencing implementations/scripts.
abstract void	checkFencingConfigured()
abstract InetSocketAddress	getAddress()
abstract org.apache.hadoop.ha.NodeFencer	getFencer()
Map<String,String>	getFencingParameters()
HAServiceProtocol	getProxy(Configuration conf, int timeoutMs)

Methods inherited from class java.lang.Object

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

Constructor Detail

HAServiceTarget

public HAServiceTarget()

Method Detail

getAddress

public abstract InetSocketAddress getAddress()

Returns:

the IPC address of the target node.

getFencer

public abstract org.apache.hadoop.ha.NodeFencer getFencer()

Returns:

a Fencer implementation configured for this target node

checkFencingConfigured

public abstract void checkFencingConfigured()
                                     throws BadFencingConfigurationException

Throws:

BadFencingConfigurationException - if the fencing configuration appears to be invalid. This is divorced from the above getFencer() method so that the configuration can be checked during the pre-flight phase of failover.

getProxy

public HAServiceProtocol getProxy(Configuration conf,
                                  int timeoutMs)
                           throws IOException

Returns:

a proxy to connect to the target HA Service.

Throws:

IOException

getFencingParameters

public final Map<String,String> getFencingParameters()

addFencingParameters

protected void addFencingParameters(Map<String,String> ret)

Hook to allow subclasses to add any parameters they would like to expose to fencing implementations/scripts. Fencing methods are free to use this map as they see fit -- notably, the shell script implementation takes each entry, prepends 'target_', substitutes '_' for '.', and adds it to the environment of the script. Subclass implementations should be sure to delegate to the superclass implementation as well as adding their own keys.

Parameters:

ret - map which can be mutated to pass parameters to the fencer