org.apache.hadoop.hdfs.server.namenode

类 SecondaryNameNode

java.lang.Object

org.apache.hadoop.hdfs.server.namenode.SecondaryNameNode

所有已实现的接口:

Runnable

public class SecondaryNameNode
extends Object
implements Runnable

The Secondary NameNode is a helper to the primary NameNode. The Secondary is responsible for supporting periodic checkpoints of the HDFS metadata. The current design allows only one Secondary NameNode per HDFs cluster. The Secondary NameNode is a daemon that periodically wakes up (determined by the schedule specified in the configuration), triggers a periodic checkpoint and then goes back to sleep. The Secondary NameNode uses the ClientProtocol to talk to the primary NameNode.

字段概要

字段

限定符和类型	字段和说明
static org.apache.commons.logging.Log	LOG

构造器概要

构造器

构造器和说明
SecondaryNameNode(Configuration conf) Create a connection to the primary namenode.

方法概要

方法

限定符和类型	方法和说明
void	doWork()
static InetSocketAddress	getHttpAddress(Configuration conf)
static void	main(String[] argv) main() has some simple utility methods.
void	run()
void	shutdown() Shut down this instance of the datanode.
String	toString()

从类继承的方法 java.lang.Object

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

字段详细资料

LOG

public static final org.apache.commons.logging.Log LOG

构造器详细资料

SecondaryNameNode

public SecondaryNameNode(Configuration conf)
                  throws IOException

Create a connection to the primary namenode.

抛出:

IOException

方法详细资料

toString

public String toString()

覆盖:

toString 在类中 Object

getHttpAddress

public static InetSocketAddress getHttpAddress(Configuration conf)

shutdown

public void shutdown()

Shut down this instance of the datanode. Returns only after shutdown is complete.

run

public void run()

指定者:

run 在接口中 Runnable

doWork

public void doWork()

main

public static void main(String[] argv)
                 throws Exception

main() has some simple utility methods.

参数:

argv - Command line parameters.

抛出:

Exception - if the filesystem does not exist.