Localhost-only pseudo-distributed hadoop installation - hadoop

I am trying to make a pseudo-distributed Hadoop installation on my Gentoo machine. I want nothing to be visible from the outside network - e.g. jobtracker and namenode web interfaces - localhost:50030 and localhost:50070. However, I noticed that I can access these from within my home network.
How do I restrict all daemons to listen to localhost only?
I've used the configuration suggested by Hadoop:
core-site.xml
1 <?xml version="1.0"?>
2 <?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
3
4 <!-- Put site-specific property overrides in this file. -->
5
6 <configuration>
7 <property>
8 <name>fs.default.name</name>
9 <value>hdfs://127.0.0.1:9000</value>
10 </property>
11 </configuration>
mapred-site.xml
1 <?xml version="1.0"?>
2 <?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
3
4 <!-- Put site-specific property overrides in this file. -->
5
6 <configuration>
7 <property>
8 <name>mapred.job.tracker</name>
9 <value>127.0.0.1:9001</value>
10 </property>
11 </configuration>
I also enforced IPv4 (taken from this quide):
hadoop-env.sh
export HADOOP_OPTS=-Djava.net.preferIPv4Stack=true

Related

HBase to Use HDFS HA

I am trying to setup hbase ha with Hadoop HA.
I have set up Hadoop HA, and tested it.
But in HBase setup, while starting, I am getting the following error:
2020-05-02 16:11:09,336 INFO [main] ipc.RpcServer: regionserver/cluster-hadoop-01/172.18.20.3:16020: started 10 reader(s) listening on port=16020
2020-05-02 16:11:09,473 INFO [main] metrics.MetricRegistries: Loaded MetricRegistries class org.apache.hadoop.hbase.metrics.impl.MetricRegistriesImpl
2020-05-02 16:11:09,840 ERROR [main] regionserver.HRegionServerCommandLine: Region server exiting
java.lang.RuntimeException: Failed construction of Regionserver: class org.apache.hadoop.hbase.regionserver.HRegionServer
at org.apache.hadoop.hbase.regionserver.HRegionServer.constructRegionServer(HRegionServer.java:2896)
at org.apache.hadoop.hbase.regionserver.HRegionServerCommandLine.start(HRegionServerCommandLine.java:64)
at org.apache.hadoop.hbase.regionserver.HRegionServerCommandLine.run(HRegionServerCommandLine.java:87)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:76)
at org.apache.hadoop.hbase.util.ServerCommandLine.doMain(ServerCommandLine.java:127)
at org.apache.hadoop.hbase.regionserver.HRegionServer.main(HRegionServer.java:2911)
Caused by: java.lang.reflect.InvocationTargetException
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:423)
at org.apache.hadoop.hbase.regionserver.HRegionServer.constructRegionServer(HRegionServer.java:2894)
... 5 more
Caused by: java.lang.IllegalArgumentException: java.net.UnknownHostException: hdfscluster
at org.apache.hadoop.security.SecurityUtil.buildTokenService(SecurityUtil.java:417)
at org.apache.hadoop.hdfs.NameNodeProxiesClient.createProxyWithClientProtocol(NameNodeProxiesClient.java:132)
at org.apache.hadoop.hdfs.DFSClient.<init>(DFSClient.java:351)
at org.apache.hadoop.hdfs.DFSClient.<init>(DFSClient.java:285)
at org.apache.hadoop.hdfs.DistributedFileSystem.initialize(DistributedFileSystem.java:160)
at org.apache.hadoop.fs.FileSystem.createFileSystem(FileSystem.java:2812)
at org.apache.hadoop.fs.FileSystem.access$200(FileSystem.java:100)
at org.apache.hadoop.fs.FileSystem$Cache.getInternal(FileSystem.java:2849)
at org.apache.hadoop.fs.FileSystem$Cache.get(FileSystem.java:2831)
at org.apache.hadoop.fs.FileSystem.get(FileSystem.java:389)
at org.apache.hadoop.fs.Path.getFileSystem(Path.java:356)
at org.apache.hadoop.hbase.util.CommonFSUtils.getRootDir(CommonFSUtils.java:309)
at org.apache.hadoop.hbase.util.CommonFSUtils.isValidWALRootDir(CommonFSUtils.java:358)
at org.apache.hadoop.hbase.util.CommonFSUtils.getWALRootDir(CommonFSUtils.java:334)
at org.apache.hadoop.hbase.regionserver.HRegionServer.initializeFileSystem(HRegionServer.java:683)
at org.apache.hadoop.hbase.regionserver.HRegionServer.<init>(HRegionServer.java:626)
... 10 more
Caused by: java.net.UnknownHostException: hdfscluster
... 26 more
I think my HBase setup doesn't recognize my nameservice hdfscluster.
I tried Hadoop 2.X and Hadoop 3.X.
Hadoop 2.X: Hadoop 2.10.0 & HBase 1.6.0 & JDK 1.8.0_251 & ZooKeeper 3.6.0.
Hadoop 3.X: Hadoop 3.2.1 & HBase 2.2.4 & JDK 1.8.0_251 & ZooKeeper 3.6.0.
OS Version: Ubuntu 16.04.6
My core-site.xml has
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<configuration>
<property>
<name>fs.defaultFS</name>
<value>hdfs://hdfscluster</value>
</property>
<property>
<name>io.file.buffer.size</name>
<value>131072</value>
</property>
<property>
<name>hadoop.tmp.dir</name>
<value>file:/data/hadoop/tmp</value>
</property>
<property>
<name>ha.zookeeper.quorum</name>
<value>cluster-hadoop-01:2181,cluster-hadoop-02:2181,cluster-hadoop-03:2181</value>
</property>
</configuration>
My hdfs-site.xml has
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<configuration>
<property>
<name>dfs.replication</name>
<value>2</value>
</property>
<property>
<name>dfs.namenode.name.dir</name>
<value>file:/data/hadoop/data/hdfs/name</value>
</property>
<property>
<name>dfs.datanode.data.dir</name>
<value>file:/data/hadoop/data/hdfs/data</value>
</property>
<property>
<name>dfs.nameservices</name>
<value>hdfscluster</value>
</property>
<property>
<name>dfs.ha.namenodes.hdfscluster</name>
<value>nn-01,nn-02</value>
</property>
<property>
<name>dfs.namenode.rpc-address.hdfscluster.nn-01</name>
<value>cluster-hadoop-01:8020</value>
</property>
<property>
<name>dfs.namenode.rpc-address.hdfscluster.nn-02</name>
<value>cluster-hadoop-02:8020</value>
</property>
<property>
<name>dfs.namenode.http-address.hdfscluster.nn-01</name>
<value>cluster-hadoop-01:9870</value>
</property>
<property>
<name>dfs.namenode.http-address.hdfscluster.nn-02</name>
<value>cluster-hadoop-02:9870</value>
</property>
<property>
<name>dfs.namenode.shared.edits.dir</name>
<value>qjournal://cluster-hadoop-01:8485;cluster-hadoop-02:8485;cluster-hadoop-03:8485/hdfscluster</value>
</property>
<property>
<name>dfs.journalnode.edits.dir</name>
<value>/data/hadoop/tmp/journalnode</value>
</property>
<property>
<name>dfs.ha.automatic-failover.enabled</name>
<value>true</value>
</property>
<property>
<name>dfs.client.failover.proxy.provider</name>
<value>org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider</value>
</property>
<property>
<name>dfs.ha.fencing.methods</name>
<value>sshfence(hadoop:22)</value>
</property>
<property>
<name>dfs.ha.fencing.ssh.private-key-files</name>
<value>/home/hadoop/.ssh/id_rsa</value>
</property>
<property>
<name>dfs.ha.fencing.ssh.connect-timeout</name>
<value>30000</value>
</property>
</configuration>
My hbase-site.xml has
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<configuration>
<property>
<name>hbase.rootdir</name>
<value>hdfs://hdfscluster/hbase</value>
</property>
<property>
<name>hbase.cluster.distributed</name>
<value>true</value>
</property>
<property>
<name>hbase.zookeeper.quorum</name>
<value>cluster-hadoop-01,cluster-hadoop-02,cluster-hadoop-03</value>
</property>
<property>
<name>hbase.zookeeper.property.clientPort</name>
<value>2181</value>
</property>
<property>
<name>hbase.zookeeper.property.dataDir</name>
<value>/data/zookeeper/data</value>
</property>
<property>
<name>hbase.tmp.dir</name>
<value>/data/hbase/tmp</value>
</property>
</configuration>
My hbase-env.sh has
export JAVA_HOME="/opt/jdk"
export HBASE_MANAGES_ZK=false
export HADOOP_HOME="/opt/hadoop"
export HBASE_CLASSPATH=".:${HADOOP_HOME}/etc/hadoop"
export HBASE_LOG_DIR="/data/hbase/log"
My HBase conf path:
root#cluster-hadoop-01:~# ll /opt/hbase/conf/
total 56
drwxr-xr-x 2 root root 4096 May 2 16:31 ./
drwxr-xr-x 7 root root 4096 May 2 01:18 ../
-rw-r--r-- 1 root root 18 May 2 10:36 backup-masters
lrwxrwxrwx 1 root root 36 May 2 12:04 core-site.xml -> /opt/hadoop/etc/hadoop/core-site.xml
-rw-r--r-- 1 root root 1811 Jan 6 01:24 hadoop-metrics2-hbase.properties
-rw-r--r-- 1 root root 4616 Jan 6 01:24 hbase-env.cmd
-rw-r--r-- 1 root root 7898 May 2 10:36 hbase-env.sh
-rw-r--r-- 1 root root 2257 Jan 6 01:24 hbase-policy.xml
-rw-r--r-- 1 root root 841 May 2 16:10 hbase-site.xml
lrwxrwxrwx 1 root root 36 May 2 12:04 hdfs-site.xml -> /opt/hadoop/etc/hadoop/hdfs-site.xml
-rw-r--r-- 1 root root 1169 Jan 6 01:24 log4j-hbtop.properties
-rw-r--r-- 1 root root 4949 Jan 6 01:24 log4j.properties
-rw-r--r-- 1 root root 54 May 2 10:33 regionservers
Through my continuous attempts, I found a solution, but I still do not know the reason.
Modify hdfs-site.xml configuration file:
<property>
<name>dfs.client.failover.proxy.provider.hdfscluster</name>
<value>org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider</value>
</property>
The official document does not require the nameservice id.
link: https://hadoop.apache.org/docs/current/hadoop-project-dist/hadoop-hdfs/HDFSHighAvailabilityWithQJM.html
As I am going through the same issue, I got to know that we have to use the same machines for both HBase and HDFS.
e.g.
Node-1 -> Should have Active Namenode & HBase MAster
Node-2 -> Should have StandBy Namenode, Datanode & HBase Backup Master, regionserver
Node-3 -> Should have Datanode & regionserver
NOTE: Namenode & HBase Master machines should be same and Datanode & regionserver machines should be same.
OR Another Solution, if you need to keep them on separate nodes
Just have a copy of hdfs-ste.xml in to your $HBASE_HOME/conf directory on each node of your Hbase cluster.
Make sure to have hostnames of hdfs cluster in /etc/hosts files as well.
Any further suggestions are most welcome!

browse file system link - hadoop - localhost link

I am using Hadoop 2.2 on Ubuntu.
I am able to load this link in my browser.
http://[my_ip]:50070/dfshealth.jsp
From there, when I click the "Browse the filesystem" link, I am sent to
http://localhost:50075/browseDirectory.jsp?namenodeInfoPort=50070&dir=/&nnaddr=127.0.0.1:9000
while here I think I want my_ip instead of localhost and 127.0.0.1
Also, if I type manually
http://my_ip:50075/browseDirectory.jsp?namenodeInfoPort=50070&dir=/&nnaddr=my_ip:9000
it still does not work.
The my_ip is an external/global IP throughout my whole question text.
How can I get this working? All I want is to be able to browse my HDFS filesystem from the browser.
core-site.xml
<configuration>
<property>
<name>fs.default.name</name>
<value>hdfs://localhost:9000</value>
<!-- <value>hdfs://my_ip:9000</value> -->
</property>
<!--
fs.default.name
hdfs://localhost:9000
-->
</configuration>
hdfs-site.xml
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!-- Put site-specific property overrides in this file. -->
<configuration>
<property>
<name>dfs.replication</name>
<value>1</value>
</property>
<property>
<name>dfs.namenode.name.dir</name>
<value>file:/var/lib/hadoop/hdfs/namenode</value>
</property>
<property>
<name>dfs.datanode.data.dir</name>
<value>file:/var/lib/hadoop/hdfs/datanode</value>
</property>
<!--
dfs.replication
1
dfs.namenode.name.dir
file:/var/lib/hadoop/hdfs/namenode
dfs.datanode.data.dir
file:/var/lib/hadoop/hdfs/datanode
-->
<property>
<name>dfs.http.address</name>
<value>my_ip:50070</value>
</property>
<property>
<name>dfs.datanode.http.address</name>
<value>my_ip:50075</value>
</property>
</configuration>
/etc/hosts
127.0.0.1 localhost test02
# 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
EDIT ERROR:
HTTP ERROR 500
Problem accessing /nn_browsedfscontent.jsp. Reason:
Cannot issue delegation token. Name node is in safe mode.
The reported blocks 21 has reached the threshold 0.9990 of total blocks 21. The number of live datanodes 1 has reached the minimum number 0. Safe mode will be turned off automatically in 2 seconds.
Caused by:
org.apache.hadoop.hdfs.server.namenode.SafeModeException: Cannot issue delegation token. Name node is in safe mode.
The reported blocks 21 has reached the threshold 0.9990 of total blocks 21. The number of live datanodes 1 has reached the minimum number 0. Safe mode will be turned off automatically in 2 seconds.
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getDelegationToken(FSNamesystem.java:5887)
at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.getDelegationToken(NameNodeRpcServer.java:447)
at org.apache.hadoop.hdfs.server.namenode.NamenodeJspHelper$1.run(NamenodeJspHelper.java:623)
at org.apache.hadoop.hdfs.server.namenode.NamenodeJspHelper$1.run(NamenodeJspHelper.java:620)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:422)
In your hdfs-site.xml, replace
<property>
<name>dfs.http.address</name>
<value>my_ip:50070</value>
</property>
<property>
<name>dfs.datanode.http.address</name>
<value>my_ip:50075</value>
</property>
by
<property>
<name>dfs.namenode.http-address</name>
<value>localhost:50070</value>
</property>
<property>
<name>dfs.datanode.http.address</name>
<value>localhost:50075</value>
</property>
But usually, in pseudo-ditributed mode it's not necessary to specify those properties.
Reboot your cluster after changing the properties.

Hadoop Multi-Node Cluster Installation on Ubuntu Issue - Troubleshoot

I have three Ubuntu 12.04 LTS computers that I want to install Hadoop on in a Master/Slave configuration as described here. It says to first install Hadoop as a single node and then proceed to multi-node. The single node installation works perfectly fine. I made the required changes to the /etc/hosts file and configured everything just as the guide says, but when I start the Hadoop cluster on the master, I get an error.
My computers, aptly named ironman, superman and batman, with batman (who else?) being the master node. When I do sudo bin/start-dfs.sh, the following shows up.
When I enter the password, I get this:
When I try sudo bin/start-all.sh, I get this:
I can ssh into the different terminals, but there's something that's not quite right. I checked the logs on superman/slave terminal and it says that it can't connect to batman:54310 and some zzz message. I figured my /etc/hosts is wrong but in fact, it is:
I tried to open port 54310 by changing iptables, but the output screens shown here are after I made the changes. I'm at my wit's end. Please tell me where I'm going wrong. Please do let me know if you need any more information and I will update the question accordingly. Thanks!
UPDATE: Here are my conf files.
core-site.xml Please note that I had put batman:54310 instead of the IP address. I only changed it because I thought I'd make the binding more explicit.
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!-- Put site-specific property overrides in this file. -->
<configuration>
<property>
<name>hadoop.tmp.dir</name>
<value>/app/hadoop/tmp</value>
<description>A base for other temporary directories.</description>
</property>
<property>
<name>fs.default.name</name>
<value>hdfs://130.65.153.195:54310</value>
<description>The name of the default file system. A URI whose
scheme and authority determine the FileSystem implementation. The
uri's scheme determines the config property (fs.SCHEME.impl) naming
the FileSystem implementation class. The uri's authority is used to
determine the host, port, etc. for a filesystem.</description>
</property>
</configuration>
mapred-site.xml
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!-- Put site-specific property overrides in this file. -->
<configuration>
<property>
<name>mapred.job.tracker</name>
<value>130.65.153.195:54311</value>
<description>The host and port that the MapReduce job tracker runs
at. If "local", then jobs are run in-process as a single map
and reduce task.
</description>
</property>
</configuration>
hdfs-site.xml
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!-- Put site-specific property overrides in this file. -->
<configuration>
<property>
<name>dfs.replication</name>
<value>3</value>
<description>Default block replication.
The actual number of replications can be specified when the file is created.
The default is used if replication is not specified in create time.
</description>
</property>
</configuration>
My conf/masters file is simply batman and my conf/slaves file is just:
batman
superman
ironman
Hope this clarifies things.
First things first: Make sure you can ping the master from slave and slave from master. Login to each machine individually and ping the other 2 hosts. Make sure they are reachable via their hostnames. It is possible that you have not add /etc/hosts entries in the slaves.
Secondly, you need to setup passwordless SSH access. You can use ssh-keygen -t rsa and ssh-copy-id for this. This will help remove the password prompts. It is a good idea to create a separate user for this (and not use root).
If this doesn't help, please post your log output.

hadoop: having more than one reducers under pseudo distributed environment?

I am newbie to hadoop. I have successfully configured a hadoop setup in pseudo distributed mode. I want to have multiple reducers with the option -D mapred.reduce.tasks=2 (with hadoop-streaming). however there's still only one reducer.
according to Google I'm sure that mapred.LocalJobRunner limits number of reducers to 1. But I wonder is there any workaround to have more reducers?
my hadoop configuration files:
[admin#localhost string-count-hadoop]$ cat ~/hadoop-1.1.2/conf/core-site.xml
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!-- Put site-specific property overrides in this file. -->
<configuration>
<property>
<name>fs.default.name</name>
<value>hdfs://localhost:9000</value>
</property>
<property>
<name>hadoop.tmp.dir</name>
<value>/home/admin/hadoop-data/tmp</value>
</property>
</configuration>
[admin#localhost string-count-hadoop]$ cat ~/hadoop-1.1.2/conf/mapred-site.xml
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!-- Put site-specific property overrides in this file. -->
<configuration>
<property>
<name>mapred.job.tracker</name>
<value>localhost:9001</value>
</property>
</configuration>
[admin#localhost string-count-hadoop]$ cat ~/hadoop-1.1.2/conf/hdfs-site.xml
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!-- Put site-specific property overrides in this file. -->
<configuration>
<property>
<name>dfs.name.dir</name>
<value>/home/admin/hadoop-data/name</value>
</property>
<property>
<name>dfs.data.dir</name>
<value>/home/admin/hadoop-data/data</value>
</property>
<property>
<name>dfs.replication</name>
<value>1</value>
</property>
</configuration>
the way I start job:
[admin#localhost string-count-hadoop]$ cat hadoop-startjob.sh
#!/bin/sh
~/hadoop-1.1.2/bin/hadoop jar ~/hadoop-1.1.2/contrib/streaming/hadoop-streaming-1.1.2.jar \
-D mapred.job.name=string-count \
-D mapred.reduce.tasks=2 \
-mapper mapper \
-file mapper \
-reducer reducer \
-file reducer \
-input $1 \
-output $2
[admin#localhost string-count-hadoop]$ ./hadoop-startjob.sh /z/programming/testdata/items_sequence /z/output
packageJobJar: [mapper, reducer] [] /tmp/streamjob837249979139287589.jar tmpDir=null
13/07/17 20:21:10 INFO util.NativeCodeLoader: Loaded the native-hadoop library
13/07/17 20:21:10 WARN snappy.LoadSnappy: Snappy native library not loaded
13/07/17 20:21:10 INFO mapred.FileInputFormat: Total input paths to process : 1
13/07/17 20:21:11 WARN mapred.LocalJobRunner: LocalJobRunner does not support symlinking into current working dir.
...
...
Try modifying core-site.xml's property
<property>
<name>fs.default.name</name>
<value>hdfs://localhost:9000</value>
</property>
to,
<property>
<name>fs.default.name</name>
<value>hdfs://localhost:9000/</value>
</property>
Put an extra / after 9000 and restart all the daemons.

Why doesnt Hadoop work with Windows 7 under cygwin?

I am trying to install and start hadoop 1.1.2 in cygwin on windows 7. I am getting the following issue when attempting to run a simple job:
bin/hadoop jar hadoop-*-examples.jar pi 10 100
13/04/26 17:56:10 WARN hdfs.DFSClient: DataStreamer Exception: org.apache.hadoop.ipc.RemoteException: java.io.IOException: File /user/username/PiEstimator_TMP_3_141592654/in/part0 could only be replicated to 0 nodes, instead of 1
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock(FSNamesystem.java:1639)
at org.apache.hadoop.hdfs.server.namenode.NameNode.addBlock(NameNode.java:736)
at sun.reflect.GeneratedMethodAccessor6.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
My configuration is as follows:
mapred-site.xml
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!-- Put site-specific property overrides in this file. -->
<configuration>
<property>
<name>mapred.job.tracker</name>
<value>localhost:9001</value>
</property>
</configuration>
hdfs-site.xml
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!-- Put site-specific property overrides in this file. -->
<configuration>
<property>
<name>dfs.replication</name>
<value>1</value>
</property>
</configuration>
core-site.xml
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!-- Put site-specific property overrides in this file. -->
<configuration>
<property>
<name>fs.default.name</name>
<value>hdfs://localhost:9000</value>
</property>
</configuration>
The answer is in the logs. There will be a specific exception detailed there, most likely a file access problem requiring you to chmod 755 -R some directory and its contents.
This error not because you are trying to Hadoop on Windows. It's because there is some problem with your DataNode. Along with the point which Chris Gerken has made, there could be some other reasons as well. I had answered a similar question recently. You should have a look at it. Upload data to HDFS running in Amazon EC2 from local non-Hadoop Machine

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