org.apache.hadoop.hdfs
Class NameNodeProxies

java.lang.Object
  org.apache.hadoop.hdfs.NameNodeProxies

public class NameNodeProxies
extends Object

Create proxy objects to communicate with a remote NN. All remote access to an NN should be funneled through this class. Most of the time you'll want to use createProxy(Configuration, URI, Class), which will create either an HA- or non-HA-enabled client proxy as appropriate.

Nested Class Summary

static class

NameNodeProxies.ProxyAndInfo<PROXYTYPE> Wrapper for a client proxy as well as its associated service ID.

Constructor Summary

NameNodeProxies()

Method Summary

static <T> org.apache.hadoop.io.retry.FailoverProxyProvider<T>	createFailoverProxyProvider(org.apache.hadoop.conf.Configuration conf, Class<org.apache.hadoop.io.retry.FailoverProxyProvider<T>> failoverProxyProviderClass, Class<T> xface, URI nameNodeUri) Creates the Failover proxy provider instance
static <T> NameNodeProxies.ProxyAndInfo<T>	createNonHAProxy(org.apache.hadoop.conf.Configuration conf, InetSocketAddress nnAddr, Class<T> xface, org.apache.hadoop.security.UserGroupInformation ugi, boolean withRetries) Creates an explicitly non-HA-enabled proxy object.
static <T> NameNodeProxies.ProxyAndInfo<T>	createProxy(org.apache.hadoop.conf.Configuration conf, URI nameNodeUri, Class<T> xface) Creates the namenode proxy with the passed protocol.
static <T> Class<org.apache.hadoop.io.retry.FailoverProxyProvider<T>>	getFailoverProxyProviderClass(org.apache.hadoop.conf.Configuration conf, URI nameNodeUri, Class<T> xface) Gets the configured Failover proxy provider's class

Methods inherited from class java.lang.Object

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

Constructor Detail

NameNodeProxies

public NameNodeProxies()

Method Detail

createProxy

public static <T> NameNodeProxies.ProxyAndInfo<T> createProxy(org.apache.hadoop.conf.Configuration conf,
                                                              URI nameNodeUri,
                                                              Class<T> xface)
                                                   throws IOException

Creates the namenode proxy with the passed protocol. This will handle creation of either HA- or non-HA-enabled proxy objects, depending upon if the provided URI is a configured logical URI.

Parameters:

conf - the configuration containing the required IPC properties, client failover configurations, etc.

nameNodeUri - the URI pointing either to a specific NameNode or to a logical nameservice.

xface - the IPC interface which should be created

Returns:

an object containing both the proxy and the associated delegation token service it corresponds to

Throws:

IOException - if there is an error creating the proxy

createNonHAProxy

public static <T> NameNodeProxies.ProxyAndInfo<T> createNonHAProxy(org.apache.hadoop.conf.Configuration conf,
                                                                   InetSocketAddress nnAddr,
                                                                   Class<T> xface,
                                                                   org.apache.hadoop.security.UserGroupInformation ugi,
                                                                   boolean withRetries)
                                                        throws IOException

Creates an explicitly non-HA-enabled proxy object. Most of the time you don't want to use this, and should instead use createProxy(org.apache.hadoop.conf.Configuration, java.net.URI, java.lang.Class).

Parameters:

conf - the configuration object

nnAddr - address of the remote NN to connect to

xface - the IPC interface which should be created

ugi - the user who is making the calls on the proxy object

withRetries - certain interfaces have a non-standard retry policy

Returns:

an object containing both the proxy and the associated delegation token service it corresponds to

Throws:

IOException

getFailoverProxyProviderClass

public static <T> Class<org.apache.hadoop.io.retry.FailoverProxyProvider<T>> getFailoverProxyProviderClass(org.apache.hadoop.conf.Configuration conf,
                                                                                                           URI nameNodeUri,
                                                                                                           Class<T> xface)
                                                                                                throws IOException

Gets the configured Failover proxy provider's class

Throws:

IOException

createFailoverProxyProvider

public static <T> org.apache.hadoop.io.retry.FailoverProxyProvider<T> createFailoverProxyProvider(org.apache.hadoop.conf.Configuration conf,
                                                                                                  Class<org.apache.hadoop.io.retry.FailoverProxyProvider<T>> failoverProxyProviderClass,
                                                                                                  Class<T> xface,
                                                                                                  URI nameNodeUri)
                                                                                       throws IOException

Creates the Failover proxy provider instance

Throws:

IOException