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

Constructors

Constructor and Description
HAServiceTarget()

Method Summary

Modifier and Type	Method and Description
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()
InetSocketAddress	getHealthMonitorAddress() Returns an optional separate RPC server address for health checks at the target node.
HAServiceProtocol	getHealthMonitorProxy(Configuration conf, int timeoutMs) Returns a proxy to connect to the target HA service for health monitoring.
HAServiceProtocol	getHealthMonitorProxy(Configuration conf, int timeoutMs, int retries)
HAServiceProtocol	getProxy(Configuration conf, int timeoutMs)
abstract InetSocketAddress	getZKFCAddress()
org.apache.hadoop.ha.ZKFCProtocol	getZKFCProxy(Configuration conf, int timeoutMs)
boolean	isAutoFailoverEnabled()
boolean	supportObserver()

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.

getHealthMonitorAddress

public InetSocketAddress getHealthMonitorAddress()

Returns an optional separate RPC server address for health checks at the target node. If defined, then this address is used by the health monitor for the HAServiceProtocol.monitorHealth() and HAServiceProtocol.getServiceStatus() calls. This can be useful for separating out these calls onto separate RPC handlers to protect against resource exhaustion in the main RPC handler pool. If null (which is the default implementation), then all RPC calls go to the address defined by getAddress().

Returns:

IPC address of the lifeline RPC server on the target node, or null if no lifeline RPC server is used

getZKFCAddress

public abstract InetSocketAddress getZKFCAddress()

Returns:

the IPC address of the ZKFC on 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

getHealthMonitorProxy

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

Returns a proxy to connect to the target HA service for health monitoring. If getHealthMonitorAddress() is implemented to return a non-null address, then this proxy will connect to that address. Otherwise, the returned proxy defaults to using getAddress(), which means this method's behavior is identical to getProxy(Configuration, int).

Parameters:

conf - Configuration

timeoutMs - timeout in milliseconds

Returns:

a proxy to connect to the target HA service for health monitoring

Throws:

IOException - if there is an error

getHealthMonitorProxy

public HAServiceProtocol getHealthMonitorProxy(Configuration conf,
                                               int timeoutMs,
                                               int retries)
                                        throws IOException

Throws:

IOException

getZKFCProxy

public org.apache.hadoop.ha.ZKFCProtocol getZKFCProxy(Configuration conf,
                                                      int timeoutMs)
                                               throws IOException

Returns:

a proxy to the ZKFC which is associated with this 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

isAutoFailoverEnabled

public boolean isAutoFailoverEnabled()

Returns:

true if auto failover should be considered enabled

supportObserver

public boolean supportObserver()

Returns:

true if this target supports the Observer state, false otherwise.