我想在伪分布式模式下设置一个hadoop集群。我成功地执行了所有的设置步骤，包括在我的机器上启动namenode、datanode、jobtracker和tasktracker。
然后我试着运行一些示范程序，并面对 java.net.ConnectException: Connection refused 错误。我回到了在独立模式下运行某些操作的第一步，遇到了同样的问题。
我甚至对所有安装步骤进行了三次检查，不知道如何修复它(我是hadoop的新手，也是ubuntu的初学者，因此，如果提供任何指南或提示，我恳请您考虑一下。
这是我一直收到的错误输出：

hduser@marta-komputer:/usr/local/hadoop$ bin/hadoop jar share/hadoop/mapreduce/hadoop-mapreduce-examples-2.6.0.jar grep input output 'dfs[a-z.]+'
15/02/22 18:23:04 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
15/02/22 18:23:04 INFO client.RMProxy: Connecting to ResourceManager at /0.0.0.0:8032
java.net.ConnectException: Call From marta-komputer/127.0.1.1 to localhost:9000 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:408)
    at org.apache.hadoop.net.NetUtils.wrapWithMessage(NetUtils.java:791)
    at org.apache.hadoop.net.NetUtils.wrapException(NetUtils.java:731)
    at org.apache.hadoop.ipc.Client.call(Client.java:1472)
    at org.apache.hadoop.ipc.Client.call(Client.java:1399)
    at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:232)
    at com.sun.proxy.$Proxy9.delete(Unknown Source)
    at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.delete(ClientNamenodeProtocolTranslatorPB.java:521)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:187)
    at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:102)
    at com.sun.proxy.$Proxy10.delete(Unknown Source)
    at org.apache.hadoop.hdfs.DFSClient.delete(DFSClient.java:1929)
    at org.apache.hadoop.hdfs.DistributedFileSystem$12.doCall(DistributedFileSystem.java:638)
    at org.apache.hadoop.hdfs.DistributedFileSystem$12.doCall(DistributedFileSystem.java:634)
    at org.apache.hadoop.fs.FileSystemLinkResolver.resolve(FileSystemLinkResolver.java:81)
    at org.apache.hadoop.hdfs.DistributedFileSystem.delete(DistributedFileSystem.java:634)
    at org.apache.hadoop.examples.Grep.run(Grep.java:95)
    at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
    at org.apache.hadoop.examples.Grep.main(Grep.java:101)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at org.apache.hadoop.util.ProgramDriver$ProgramDescription.invoke(ProgramDriver.java:71)
    at org.apache.hadoop.util.ProgramDriver.run(ProgramDriver.java:144)
    at org.apache.hadoop.examples.ExampleDriver.main(ExampleDriver.java:74)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at org.apache.hadoop.util.RunJar.run(RunJar.java:221)
    at org.apache.hadoop.util.RunJar.main(RunJar.java:136)
Caused by: java.net.ConnectException: Connection refused
    at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
    at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:716)
    at org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:206)
    at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:530)
    at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:494)
    at org.apache.hadoop.ipc.Client$Connection.setupConnection(Client.java:607)
    at org.apache.hadoop.ipc.Client$Connection.setupIOstreams(Client.java:705)
    at org.apache.hadoop.ipc.Client$Connection.access$2800(Client.java:368)
    at org.apache.hadoop.ipc.Client.getConnection(Client.java:1521)
    at org.apache.hadoop.ipc.Client.call(Client.java:1438)
    ... 32 more

etc/hadoop/hadoop-env.sh文件：

# The java implementation to use.

export JAVA_HOME=/usr/lib/jvm/java-8-oracle

# The jsvc implementation to use. Jsvc is required to run secure datanodes

# that bind to privileged ports to provide authentication of data transfer

# protocol.  Jsvc is not required if SASL is configured for authentication of

# data transfer protocol using non-privileged ports.

# export JSVC_HOME=${JSVC_HOME}

export HADOOP_CONF_DIR=${HADOOP_CONF_DIR:-"/etc/hadoop"}

# Extra Java CLASSPATH elements.  Automatically insert capacity-scheduler.

for f in $HADOOP_HOME/contrib/capacity-scheduler/*.jar; do
  if [ "$HADOOP_CLASSPATH" ]; then
    export HADOOP_CLASSPATH=$HADOOP_CLASSPATH:$f
  else
    export HADOOP_CLASSPATH=$f
  fi
done

# The maximum amount of heap to use, in MB. Default is 1000.

# export HADOOP_HEAPSIZE=

# export HADOOP_NAMENODE_INIT_HEAPSIZE=""

# Extra Java runtime options.  Empty by default.

export HADOOP_OPTS="$HADOOP_OPTS -Djava.net.preferIPv4Stack=true"

# Command specific options appended to HADOOP_OPTS when specified

export HADOOP_NAMENODE_OPTS="-Dhadoop.security.logger=${HADOOP_SECURITY_LOGGER:-INFO,RFAS} -Dhdfs.audit.logger=${HDFS_AUDIT_LOGGER:-INFO,NullAppender} $HADOOP_NAMENODE_OPTS"
export HADOOP_DATANODE_OPTS="-Dhadoop.security.logger=ERROR,RFAS $HADOOP_DATANODE_OPTS"

export HADOOP_SECONDARYNAMENODE_OPTS="-Dhadoop.security.logger=${HADOOP_SECURITY_LOGGER:-INFO,RFAS} -Dhdfs.audit.logger=${HDFS_AUDIT_LOGGER:-INFO,NullAppender} $HADOOP_SECONDARYNAMENODE_OPTS"

export HADOOP_NFS3_OPTS="$HADOOP_NFS3_OPTS"
export HADOOP_PORTMAP_OPTS="-Xmx512m $HADOOP_PORTMAP_OPTS"

# The following applies to multiple commands (fs, dfs, fsck, distcp etc)

export HADOOP_CLIENT_OPTS="-Xmx512m $HADOOP_CLIENT_OPTS"

# HADOOP_JAVA_PLATFORM_OPTS="-XX:-UsePerfData $HADOOP_JAVA_PLATFORM_OPTS"

# On secure datanodes, user to run the datanode as after dropping privileges.

# This**MUST**be uncommented to enable secure HDFS if using privileged ports

# to provide authentication of data transfer protocol.  This**MUST NOT**be

# defined if SASL is configured for authentication of data transfer protocol

# using non-privileged ports.

export HADOOP_SECURE_DN_USER=${HADOOP_SECURE_DN_USER}

# Where log files are stored.  $HADOOP_HOME/logs by default.

# export HADOOP_LOG_DIR=${HADOOP_LOG_DIR}/$USER

# Where log files are stored in the secure data environment.

export HADOOP_SECURE_DN_LOG_DIR=${HADOOP_LOG_DIR}/${HADOOP_HDFS_USER}

# HDFS Mover specific parameters

### 

# Specify the JVM options to be used when starting the HDFS Mover.

# These options will be appended to the options specified as HADOOP_OPTS

# and therefore may override any similar flags set in HADOOP_OPTS

# 

# export HADOOP_MOVER_OPTS=""

### 

# Advanced Users Only!

### 

# The directory where pid files are stored. /tmp by default.

# NOTE: this should be set to a directory that can only be written to by

# the user that will run the hadoop daemons.  Otherwise there is the

# potential for a symlink attack.

export HADOOP_PID_DIR=${HADOOP_PID_DIR}
export HADOOP_SECURE_DN_PID_DIR=${HADOOP_PID_DIR}

# A string representing this instance of hadoop. $USER by default.

export HADOOP_IDENT_STRING=$USER

.bashrc文件hadoop相关片段：

# -- HADOOP ENVIRONMENT VARIABLES START -- #

export JAVA_HOME=/usr/lib/jvm/java-8-oracle
export HADOOP_HOME=/usr/local/hadoop
export PATH=$PATH:$HADOOP_HOME/bin
export PATH=$PATH:$HADOOP_HOME/sbin
export HADOOP_MAPRED_HOME=$HADOOP_HOME
export HADOOP_COMMON_HOME=$HADOOP_HOME
export HADOOP_HDFS_HOME=$HADOOP_HOME
export YARN_HOME=$HADOOP_HOME
export HADOOP_COMMON_LIB_NATIVE_DIR=$HADOOP_HOME/lib/native
export HADOOP_OPTS="-Djava.library.path=$HADOOP_HOME/lib"

# -- HADOOP ENVIRONMENT VARIABLES END -- #

/usr/local/hadoop/etc/hadoop/core-site.xml文件：

<configuration>

<property>
  <name>hadoop.tmp.dir</name>
  <value>/usr/local/hadoop_tmp</value>
  <description>A base for other temporary directories.</description>
</property>

<property>
<name>fs.default.name</name>
<value>hdfs://localhost:9000</value>
</property>

</configuration>

/usr/local/hadoop/etc/hadoop/hdfs-site.xml文件：

<configuration>
<property>
      <name>dfs.replication</name>
      <value>1</value>
 </property>
 <property>
      <name>dfs.namenode.name.dir</name>
      <value>file:/usr/local/hadoop_tmp/hdfs/namenode</value>
 </property>
 <property>
      <name>dfs.datanode.data.dir</name>
      <value>file:/usr/local/hadoop_tmp/hdfs/datanode</value>
 </property>
</configuration>

/usr/local/hadoop/etc/hadoop/yarn-site.xml文件：

<configuration> 
<property>
      <name>yarn.nodemanager.aux-services</name>
      <value>mapreduce_shuffle</value>
</property>
<property>
      <name>yarn.nodemanager.aux-services.mapreduce.shuffle.class</name>
      <value>org.apache.hadoop.mapred.ShuffleHandler</value>
</property>
</configuration>

/usr/local/hadoop/etc/hadoop/mapred-site.xml文件：

<configuration>
<property>
      <name>mapreduce.framework.name</name>
      <value>yarn</value>
</property>
<configuration>

跑步 hduser@marta-komputer:/usr/local/hadoop$ bin/hdfs namenode -format 结果输出如下（我用 (...) ):

hduser@marta-komputer:/usr/local/hadoop$ bin/hdfs namenode -format
15/02/22 18:50:47 INFO namenode.NameNode: STARTUP_MSG: 
/************************************************************
STARTUP_MSG: Starting NameNode
STARTUP_MSG:   host = marta-komputer/127.0.1.1
STARTUP_MSG:   args = [-format]
STARTUP_MSG:   version = 2.6.0
STARTUP_MSG:   classpath = /usr/local/hadoop/etc/hadoop:/usr/local/hadoop/share/hadoop/common/lib/htrace-core-3.0.4.jar:/usr/local/hadoop/share/hadoop/common/lib/commons-cli (...)2.6.0.jar:/usr/local/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-client-common-2.6.0.jar:/usr/local/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-client-hs-2.6.0.jar:/usr/local/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-client-app-2.6.0.jar:/usr/local/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-client-shuffle-2.6.0.jar:/usr/local/hadoop/contrib/capacity-scheduler/*.jar
STARTUP_MSG:   build = https://git-wip-us.apache.org/repos/asf/hadoop.git -r e3496499ecb8d220fba99dc5ed4c99c8f9e33bb1; compiled by 'jenkins' on 2014-11-13T21:10Z
STARTUP_MSG:   java = 1.8.0_31

************************************************************/

15/02/22 18:50:47 INFO namenode.NameNode: registered UNIX signal handlers for [TERM, HUP, INT]
15/02/22 18:50:47 INFO namenode.NameNode: createNameNode [-format]
15/02/22 18:50:47 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Formatting using clusterid: CID-0b65621a-eab3-47a4-bfd0-62b5596a940c
15/02/22 18:50:48 INFO namenode.FSNamesystem: No KeyProvider found.
15/02/22 18:50:48 INFO namenode.FSNamesystem: fsLock is fair:true
15/02/22 18:50:48 INFO blockmanagement.DatanodeManager: dfs.block.invalidate.limit=1000
15/02/22 18:50:48 INFO blockmanagement.DatanodeManager: dfs.namenode.datanode.registration.ip-hostname-check=true
15/02/22 18:50:48 INFO blockmanagement.BlockManager: dfs.namenode.startup.delay.block.deletion.sec is set to 000:00:00:00.000
15/02/22 18:50:48 INFO blockmanagement.BlockManager: The block deletion will start around 2015 Feb 22 18:50:48
15/02/22 18:50:48 INFO util.GSet: Computing capacity for map BlocksMap
15/02/22 18:50:48 INFO util.GSet: VM type       = 64-bit
15/02/22 18:50:48 INFO util.GSet: 2.0% max memory 889 MB = 17.8 MB
15/02/22 18:50:48 INFO util.GSet: capacity      = 2^21 = 2097152 entries
15/02/22 18:50:48 INFO blockmanagement.BlockManager: dfs.block.access.token.enable=false
15/02/22 18:50:48 INFO blockmanagement.BlockManager: defaultReplication         = 1
15/02/22 18:50:48 INFO blockmanagement.BlockManager: maxReplication             = 512
15/02/22 18:50:48 INFO blockmanagement.BlockManager: minReplication             = 1
15/02/22 18:50:48 INFO blockmanagement.BlockManager: maxReplicationStreams      = 2
15/02/22 18:50:48 INFO blockmanagement.BlockManager: shouldCheckForEnoughRacks  = false
15/02/22 18:50:48 INFO blockmanagement.BlockManager: replicationRecheckInterval = 3000
15/02/22 18:50:48 INFO blockmanagement.BlockManager: encryptDataTransfer        = false
15/02/22 18:50:48 INFO blockmanagement.BlockManager: maxNumBlocksToLog          = 1000
15/02/22 18:50:48 INFO namenode.FSNamesystem: fsOwner             = hduser (auth:SIMPLE)
15/02/22 18:50:48 INFO namenode.FSNamesystem: supergroup          = supergroup
15/02/22 18:50:48 INFO namenode.FSNamesystem: isPermissionEnabled = true
15/02/22 18:50:48 INFO namenode.FSNamesystem: HA Enabled: false
15/02/22 18:50:48 INFO namenode.FSNamesystem: Append Enabled: true
15/02/22 18:50:48 INFO util.GSet: Computing capacity for map INodeMap
15/02/22 18:50:48 INFO util.GSet: VM type       = 64-bit
15/02/22 18:50:48 INFO util.GSet: 1.0% max memory 889 MB = 8.9 MB
15/02/22 18:50:48 INFO util.GSet: capacity      = 2^20 = 1048576 entries
15/02/22 18:50:48 INFO namenode.NameNode: Caching file names occuring more than 10 times
15/02/22 18:50:48 INFO util.GSet: Computing capacity for map cachedBlocks
15/02/22 18:50:48 INFO util.GSet: VM type       = 64-bit
15/02/22 18:50:48 INFO util.GSet: 0.25% max memory 889 MB = 2.2 MB
15/02/22 18:50:48 INFO util.GSet: capacity      = 2^18 = 262144 entries
15/02/22 18:50:48 INFO namenode.FSNamesystem: dfs.namenode.safemode.threshold-pct = 0.9990000128746033
15/02/22 18:50:48 INFO namenode.FSNamesystem: dfs.namenode.safemode.min.datanodes = 0
15/02/22 18:50:48 INFO namenode.FSNamesystem: dfs.namenode.safemode.extension     = 30000
15/02/22 18:50:48 INFO namenode.FSNamesystem: Retry cache on namenode is enabled
15/02/22 18:50:48 INFO namenode.FSNamesystem: Retry cache will use 0.03 of total heap and retry cache entry expiry time is 600000 millis
15/02/22 18:50:48 INFO util.GSet: Computing capacity for map NameNodeRetryCache
15/02/22 18:50:48 INFO util.GSet: VM type       = 64-bit
15/02/22 18:50:48 INFO util.GSet: 0.029999999329447746% max memory 889 MB = 273.1 KB
15/02/22 18:50:48 INFO util.GSet: capacity      = 2^15 = 32768 entries
15/02/22 18:50:48 INFO namenode.NNConf: ACLs enabled? false
15/02/22 18:50:48 INFO namenode.NNConf: XAttrs enabled? true
15/02/22 18:50:48 INFO namenode.NNConf: Maximum size of an xattr: 16384
Re-format filesystem in Storage Directory /usr/local/hadoop_tmp/hdfs/namenode ? (Y or N) Y
15/02/22 18:50:50 INFO namenode.FSImage: Allocated new BlockPoolId: BP-948369552-127.0.1.1-1424627450316
15/02/22 18:50:50 INFO common.Storage: Storage directory /usr/local/hadoop_tmp/hdfs/namenode has been successfully formatted.
15/02/22 18:50:50 INFO namenode.NNStorageRetentionManager: Going to retain 1 images with txid >= 0
15/02/22 18:50:50 INFO util.ExitUtil: Exiting with status 0
15/02/22 18:50:50 INFO namenode.NameNode: SHUTDOWN_MSG: 
/************************************************************
SHUTDOWN_MSG: Shutting down NameNode at marta-komputer/127.0.1.1

************************************************************/

启动 dfs 以及 yarn 结果如下：

hduser@marta-komputer:/usr/local/hadoop$ start-dfs.sh
15/02/22 18:53:05 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Starting namenodes on [localhost]
localhost: starting namenode, logging to /usr/local/hadoop/logs/hadoop-hduser-namenode-marta-komputer.out
localhost: starting datanode, logging to /usr/local/hadoop/logs/hadoop-hduser-datanode-marta-komputer.out
Starting secondary namenodes [0.0.0.0]
0.0.0.0: starting secondarynamenode, logging to /usr/local/hadoop/logs/hadoop-hduser-secondarynamenode-marta-komputer.out
15/02/22 18:53:20 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
hduser@marta-komputer:/usr/local/hadoop$ start-yarn.sh
starting yarn daemons
starting resourcemanager, logging to /usr/local/hadoop/logs/yarn-hduser-resourcemanager-marta-komputer.out
localhost: starting nodemanager, logging to /usr/local/hadoop/logs/yarn-hduser-nodemanager-marta-komputer.out

打电话 jps 之后不久：

hduser@marta-komputer:/usr/local/hadoop$ jps
11696 ResourceManager
11842 NodeManager
11171 NameNode
11523 SecondaryNameNode
12167 Jps

netstat输出：

hduser@marta-komputer:/usr/local/hadoop$ sudo netstat -lpten | grep java
tcp        0      0 0.0.0.0:8088            0.0.0.0:*               LISTEN      1001       690283      11696/java      
tcp        0      0 0.0.0.0:42745           0.0.0.0:*               LISTEN      1001       684574      11842/java      
tcp        0      0 0.0.0.0:13562           0.0.0.0:*               LISTEN      1001       680955      11842/java      
tcp        0      0 0.0.0.0:8030            0.0.0.0:*               LISTEN      1001       684531      11696/java      
tcp        0      0 0.0.0.0:8031            0.0.0.0:*               LISTEN      1001       684524      11696/java      
tcp        0      0 0.0.0.0:8032            0.0.0.0:*               LISTEN      1001       680879      11696/java      
tcp        0      0 0.0.0.0:8033            0.0.0.0:*               LISTEN      1001       687392      11696/java      
tcp        0      0 0.0.0.0:8040            0.0.0.0:*               LISTEN      1001       680951      11842/java      
tcp        0      0 127.0.0.1:9000          0.0.0.0:*               LISTEN      1001       687242      11171/java      
tcp        0      0 0.0.0.0:8042            0.0.0.0:*               LISTEN      1001       680956      11842/java      
tcp        0      0 0.0.0.0:50090           0.0.0.0:*               LISTEN      1001       690252      11523/java      
tcp        0      0 0.0.0.0:50070           0.0.0.0:*               LISTEN      1001       687239      11171/java

/etc/hosts文件：

127.0.0.1       localhost
127.0.1.1       marta-komputer

# The following lines are desirable for IPv6 capable hosts

::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

====================================================

更新1。
我更新了core-site.xml，现在：

<property>
<name>fs.default.name</name>
<value>hdfs://marta-komputer:9000</value>
</property>

但我一直收到错误-现在开始是：

15/03/01 00:59:34 INFO client.RMProxy: Connecting to ResourceManager at /0.0.0.0:8032
java.net.ConnectException: Call From marta-komputer.home/192.168.1.8 to marta-komputer:9000 failed on connection exception:     java.net.ConnectException: Connection refused; For more details see:    http://wiki.apache.org/hadoop/ConnectionRefused

我也注意到 telnet localhost 9000 不工作：

hduser@marta-komputer:~$ telnet localhost 9000
Trying 127.0.0.1...
telnet: Unable to connect to remote host: Connection refused