How to Set Up Hadoop Multi-Node Cluster on CentOS 7/6

Written by Rahul, Updated on July 22, 2013

The Apache Hadoop software library is a framework that allows for the distributed processing of large data sets across clusters of computers using simple programming models.

Our earlier article about hadoop was describing to how to setup single node cluster. This article will help you for step by step installing and configuring Hadoop Multi-Node Cluster on CentOS/RHEL 6.

Setup Details:

Hadoop Master: 192.168.1.15 ( hadoop-master )
Hadoop Slave : 192.168.1.16 ( hadoop-slave-1 )
Hadoop Slave : 192.168.1.17 ( hadoop-slave-2 )

Step 1. Install Java

Before installing hadoop make sure you have java installed on all nodes of hadoop cluster systems.

# java -version

java version "1.7.0_75"
Java(TM) SE Runtime Environment (build 1.7.0_75-b13)
Java HotSpot(TM) 64-Bit Server VM (build 24.75-b04, mixed mode)

If you do not have java installed use following article to install Java.

Steps to install JAVA 7 on CentOS/RHEL 7/6/5

Step 2. Create User Account

Create a system user account on both master and slave systems to use for hadoop installation

# useradd hadoop
# passwd hadoop

Changing password for user hadoop.
New password:
Retype new password:
passwd: all authentication tokens updated successfully.

Step 3: Add FQDN Mapping

Edit /etc/hosts file on all master and slave servers and add following entries.

# vim /etc/hosts

192.168.1.15 hadoop-master
192.168.1.16 hadoop-slave-1
192.168.1.17 hadoop-slave-2

Step 4. Configuring Key Based Login

It’s required to set up hadoop user to ssh itself without password. Use following commands to configure auto login between all hadoop cluster servers..

# su - hadoop
$ ssh-keygen -t rsa
$ ssh-copy-id -i ~/.ssh/id_rsa.pub [email protected]
$ ssh-copy-id -i ~/.ssh/id_rsa.pub [email protected]
$ ssh-copy-id -i ~/.ssh/id_rsa.pub [email protected]
$ chmod 0600 ~/.ssh/authorized_keys
$ exit

Step 5. Download and Extract Hadoop Source

Download hadoop latest available version from its official site at hadoop-master server only.

# mkdir /opt/hadoop
# cd /opt/hadoop/
# wget http://apache.mesi.com.ar/hadoop/common/hadoop-1.2.0/hadoop-1.2.0.tar.gz
# tar -xzf hadoop-1.2.0.tar.gz
# mv hadoop-1.2.0 hadoop
# chown -R hadoop /opt/hadoop
# cd /opt/hadoop/hadoop/

Step 6: Configure Hadoop

First edit hadoop configuration files and make following changes.
6.1 Edit core-site.xml

# vim conf/core-site.xml

#Add the following inside the configuration tag
<property>
    <name>fs.default.name</name>
    <value>hdfs://hadoop-master:9000/</value>
</property>
<property>
    <name>dfs.permissions</name>
    <value>false</value>
</property>

6.2 Edit hdfs-site.xml

# vim conf/hdfs-site.xml

# Add the following inside the configuration tag
<property>
	<name>dfs.data.dir</name>
	<value>/opt/hadoop/hadoop/dfs/name/data</value>
	<final>true</final>
</property>
<property>
	<name>dfs.name.dir</name>
	<value>/opt/hadoop/hadoop/dfs/name</value>
	<final>true</final>
</property>
<property>
	<name>dfs.replication</name>
	<value>1</value>
</property>

6.3 Edit mapred-site.xml

# vim conf/mapred-site.xml

# Add the following inside the configuration tag
<property>
        <name>mapred.job.tracker</name>
	<value>hadoop-master:9001</value>
</property>

6.4 Edit hadoop-env.sh

# vim conf/hadoop-env.sh

export JAVA_HOME=/opt/jdk1.7.0_75
export HADOOP_OPTS=-Djava.net.preferIPv4Stack=true
export HADOOP_CONF_DIR=/opt/hadoop/hadoop/conf

Set JAVA_HOME path as per your system configuration for java.

Step 7: Copy Hadoop Source to Slave Servers

After updating above configuration, we need to copy the source files to all slaves servers.

# su - hadoop
$ cd /opt/hadoop
$ scp -r hadoop hadoop-slave-1:/opt/hadoop
$ scp -r hadoop hadoop-slave-2:/opt/hadoop

Step 8: Configure Hadoop on Master Server Only

Go to hadoop source folder on hadoop-master and do following settings.

# su - hadoop
$ cd /opt/hadoop/hadoop

$ vim conf/masters

hadoop-master

$ vim conf/slaves

hadoop-slave-1
hadoop-slave-2

Format Name Node on Hadoop Master only

# su - hadoop
$ cd /opt/hadoop/hadoop
$ bin/hadoop namenode -format

13/07/13 10:58:07 INFO namenode.NameNode: STARTUP_MSG:
/************************************************************
STARTUP_MSG: Starting NameNode
STARTUP_MSG:   host = hadoop-master/192.168.1.15
STARTUP_MSG:   args = [-format]
STARTUP_MSG:   version = 1.2.0
STARTUP_MSG:   build = https://svn.apache.org/repos/asf/hadoop/common/branches/branch-1.2 -r 1479473; compiled by 'hortonfo' on Mon May  6 06:59:37 UTC 2013
STARTUP_MSG:   java = 1.7.0_25
************************************************************/
13/07/13 10:58:08 INFO util.GSet: Computing capacity for map BlocksMap
13/07/13 10:58:08 INFO util.GSet: VM type       = 32-bit
13/07/13 10:58:08 INFO util.GSet: 2.0% max memory = 1013645312
13/07/13 10:58:08 INFO util.GSet: capacity      = 2^22 = 4194304 entries
13/07/13 10:58:08 INFO util.GSet: recommended=4194304, actual=4194304
13/07/13 10:58:08 INFO namenode.FSNamesystem: fsOwner=hadoop
13/07/13 10:58:08 INFO namenode.FSNamesystem: supergroup=supergroup
13/07/13 10:58:08 INFO namenode.FSNamesystem: isPermissionEnabled=true
13/07/13 10:58:08 INFO namenode.FSNamesystem: dfs.block.invalidate.limit=100
13/07/13 10:58:08 INFO namenode.FSNamesystem: isAccessTokenEnabled=false accessKeyUpdateInterval=0 min(s), accessTokenLifetime=0 min(s)
13/07/13 10:58:08 INFO namenode.FSEditLog: dfs.namenode.edits.toleration.length = 0
13/07/13 10:58:08 INFO namenode.NameNode: Caching file names occuring more than 10 times
13/07/13 10:58:08 INFO common.Storage: Image file of size 112 saved in 0 seconds.
13/07/13 10:58:08 INFO namenode.FSEditLog: closing edit log: position=4, editlog=/opt/hadoop/hadoop/dfs/name/current/edits
13/07/13 10:58:08 INFO namenode.FSEditLog: close success: truncate to 4, editlog=/opt/hadoop/hadoop/dfs/name/current/edits
13/07/13 10:58:08 INFO common.Storage: Storage directory /opt/hadoop/hadoop/dfs/name has been successfully formatted.
13/07/13 10:58:08 INFO namenode.NameNode: SHUTDOWN_MSG:
/************************************************************
SHUTDOWN_MSG: Shutting down NameNode at hadoop-master/192.168.1.15
************************************************************/

Step 9: Start Hadoop Services

Use the following command to start all hadoop services on Hadoop-Master

$ bin/start-all.sh

Rahul

I, Rahul Kumar am the founder and chief editor of TecAdmin.net. I am a Red Hat Certified Engineer (RHCE) and working as an IT professional since 2009..

23 Comments

isak Reply to isak to isak" aria-label=' Reply to isak to isak'> Reply to isak
April 28, 2020 at 8:02 pm
hi i take these mistake. what is the reason?
WARNING: Use of this script to execute namenode is deprecated.
WARNING: Attempting to execute replacement “hdfs namenode” instead.
WARNING: /opt/hadoop/hadoop/logs does not exist. Creating.
Error: Could not find or load main class Djava.net.preferIPv4Stack=true
aruur Reply to aruur to aruur" aria-label=' Reply to aruur to aruur'> Reply to aruur
July 25, 2019 at 8:53 pm
I cant see “Step 8: Configure Hadoop on Master Server Only” masters file and slaves file..
I use centos7 and hadoop 3.2.0
Why ??
thank u brother..
Anandachetan Reply to Anandachetan to Anandachetan" aria-label=' Reply to Anandachetan to Anandachetan'> Reply to Anandachetan
June 11, 2018 at 3:24 am
Excellent article.
Selvaesakki Reply to Selvaesakki to Selvaesakki" aria-label=' Reply to Selvaesakki to Selvaesakki'> Reply to Selvaesakki
December 8, 2017 at 5:05 pm
Hi Rahul,
Am facing below issue,Master Started but Slaves not started..
bin/start-all.sh
namenode running as process 2767. Stop it first.
hadoop-slave-1: bash: line 0: cd: /opt/hadoop/hadoop/libexec/..: No such file or directory
hadoop-slave-1: bash: /opt/hadoop/hadoop/bin/hadoop-daemon.sh: No such file or directory
hadoop-slave-2: bash: line 0: cd: /opt/hadoop/hadoop/libexec/..: No such file or directory
hadoop-slave-2: bash: /opt/hadoop/hadoop/bin/hadoop-daemon.sh: No such file or directory
hadoop-master: secondarynamenode running as process 2916. Stop it first.
jobtracker running as process 2996. Stop it first.
hadoop-slave-2: bash: line 0: cd: /opt/hadoop/hadoop/libexec/..: No such file or directory
hadoop-slave-2: bash: /opt/hadoop/hadoop/bin/hadoop-daemon.sh: No such file or directory
hadoop-slave-1: bash: line 0: cd: /opt/hadoop/hadoop/libexec/..: No such file or directory
hadoop-slave-1: bash: /opt/hadoop/hadoop/bin/hadoop-daemon.sh: No such file or directory
Selvaesakki Reply to Selvaesakki to Selvaesakki" aria-label=' Reply to Selvaesakki to Selvaesakki'> Reply to Selvaesakki
December 7, 2017 at 10:18 pm
Hi Rahul,
Am facing below issue,pls guide me
bin/start-all.sh
starting namenode, logging to /opt/hadoop/hadoop/libexec/../logs/hadoop-hadoop-namenode-ip-10-0-0-59.out
hadoop-slave-1: bash: line 0: cd: /opt/hadoop/hadoop/libexec/..: No such file or directory
hadoop-slave-1: bash: /opt/hadoop/hadoop/bin/hadoop-daemon.sh: No such file or directory
hadoop-slave-2: bash: line 0: cd: /opt/hadoop/hadoop/libexec/..: No such file or directory
hadoop-slave-2: bash: /opt/hadoop/hadoop/bin/hadoop-daemon.sh: No such file or directory
hadoop-master: starting secondarynamenode, logging to /opt/hadoop/hadoop/libexec/../logs/hadoop-hadoop-secondarynamenode-ip-10-0-0-59.out
starting jobtracker, logging to /opt/hadoop/hadoop/libexec/../logs/hadoop-hadoop-jobtracker-ip-10-0-0-59.out
hadoop-slave-2: bash: line 0: cd: /opt/hadoop/hadoop/libexec/..: No such file or directory
hadoop-slave-2: bash: /opt/hadoop/hadoop/bin/hadoop-daemon.sh: No such file or directory
hadoop-slave-1: bash: line 0: cd: /opt/hadoop/hadoop/libexec/..: No such file or directory
hadoop-slave-1: bash: /opt/hadoop/hadoop/bin/hadoop-daemon.sh: No such file or directory
[[email protected] hadoop]$ bin/stop-all.sh
stopping jobtracker
hadoop-slave-2: bash: line 0: cd: /opt/hadoop/hadoop/libexec/..: No such file or directory
hadoop-slave-2: bash: /opt/hadoop/hadoop/bin/hadoop-daemon.sh: No such file or directory
hadoop-slave-1: bash: line 0: cd: /opt/hadoop/hadoop/libexec/..: No such file or directory
hadoop-slave-1: bash: /opt/hadoop/hadoop/bin/hadoop-daemon.sh: No such file or directory
stopping namenode
hadoop-slave-2: bash: line 0: cd: /opt/hadoop/hadoop/libexec/..: No such file or directory
hadoop-slave-2: bash: /opt/hadoop/hadoop/bin/hadoop-daemon.sh: No such file or directory
hadoop-slave-1: bash: line 0: cd: /opt/hadoop/hadoop/libexec/..: No such file or directory
hadoop-slave-1: bash: /opt/hadoop/hadoop/bin/hadoop-daemon.sh: No such file or directory
hadoop-master: stopping secondarynamenode
By Selva
Dinakar N K Reply to Dinakar to Dinakar N K" aria-label=' Reply to Dinakar to Dinakar N K'> Reply to Dinakar
October 13, 2017 at 7:40 am
Hi Mr Rahul,
Could you kindly clarify me can we share hadoop single node cluster to multiple users a (group of 60). If so could you kindly help me for the same
Sam Reply to Sam to Sam" aria-label=' Reply to Sam to Sam'> Reply to Sam
December 22, 2016 at 7:48 am
Hi Rahul, great article but I got stuck on step #7. I run the scp commands, the error I got was “Access denied”. I then decided to give hadoop user on each node an administrator/root privilege. I then run the command again just to receive the follwoing error message :
[[email protected] hadoop]$ scp -r hadoop hadoop-slave-2:/opt/hadoop
[email protected]’s password:
hadoop: No such file or directory
What do you I might have done wrong? Thanks for your help in advance.
Prateek Harsh Reply to Prateek to Prateek Harsh" aria-label=' Reply to Prateek to Prateek Harsh'> Reply to Prateek
July 21, 2016 at 4:04 pm
Hi Rahul,
I have done whatever you have suggested and everything is going fine except last step to start hadoop in master after giving command start-all.sh getting error ” -bash : start-all.sh: command not found”. Even though i have given hadoop path in .bashrc file.
inner Reply to inner to inner" aria-label=' Reply to inner to inner'> Reply to inner
July 19, 2016 at 11:37 pm
If my comments will be shown here I will explain what I did to fix my problem. It is all fixed and working now!
inner Reply to inner to inner" aria-label=' Reply to inner to inner'> Reply to inner
July 19, 2016 at 8:14 pm
Finally, I have got them working now. They all are alive now, but yet I can’t put any files into hdfs:
[[email protected] hadoop]$ ./bin/hdfs dfs -put /home/hadoop/node_setup /names/node_setup
16/07/19 21:11:42 INFO hdfs.DFSClient: Exception in createBlockOutputStream
java.net.NoRouteToHostException: No route to host
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:739)
at org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:206)
at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:531)
at org.apache.hadoop.hdfs.DFSOutputStream.createSocketForPipeline(DFSOutputStream.java:1537)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.createBlockOutputStream(DFSOutputStream.java:1313)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.nextBlockOutputStream(DFSOutputStream.java:1266)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.run(DFSOutputStream.java:449)
16/07/19 21:11:42 INFO hdfs.DFSClient: Abandoning BP-1606715859-192.168.0.13-1468886056606:blk_1073741825_1001
16/07/19 21:11:42 INFO hdfs.DFSClient: Excluding datanode DatanodeInfoWithStorage[192.168.0.15:50010,DS-bb00767f-26f0-428f-b563-30c2b712fd5f,DISK]
16/07/19 21:11:42 INFO hdfs.DFSClient: Exception in createBlockOutputStream
java.net.NoRouteToHostException: No route to host
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:739)
at org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:206)
at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:531)
at org.apache.hadoop.hdfs.DFSOutputStream.createSocketForPipeline(DFSOutputStream.java:1537)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.createBlockOutputStream(DFSOutputStream.java:1313)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.nextBlockOutputStream(DFSOutputStream.java:1266)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.run(DFSOutputStream.java:449)
16/07/19 21:11:42 INFO hdfs.DFSClient: Abandoning BP-1606715859-192.168.0.13-1468886056606:blk_1073741826_1002
16/07/19 21:11:42 INFO hdfs.DFSClient: Excluding datanode DatanodeInfoWithStorage[192.168.0.16:50010,DS-c58b5570-9cd7-491b-823f-d08a67482a0f,DISK]
16/07/19 21:11:42 INFO hdfs.DFSClient: Exception in createBlockOutputStream
java.net.NoRouteToHostException: No route to host
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:739)
at org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:206)
at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:531)
at org.apache.hadoop.hdfs.DFSOutputStream.createSocketForPipeline(DFSOutputStream.java:1537)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.createBlockOutputStream(DFSOutputStream.java:1313)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.nextBlockOutputStream(DFSOutputStream.java:1266)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.run(DFSOutputStream.java:449)
16/07/19 21:11:42 INFO hdfs.DFSClient: Abandoning BP-1606715859-192.168.0.13-1468886056606:blk_1073741827_1003
16/07/19 21:11:42 INFO hdfs.DFSClient: Excluding datanode DatanodeInfoWithStorage[192.168.0.14:50010,DS-757164da-1541-43ff-9271-379abb45f774,DISK]
16/07/19 21:11:42 WARN hdfs.DFSClient: DataStreamer Exception
org.apache.hadoop.ipc.RemoteException(java.io.IOException): File /names/node_setup._COPYING_ could only be replicated to 0 nodes instead of minReplication (=1). There are 3 datanode(s) running and 3 node(s) are excluded in this operation.
at org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.chooseTarget4NewBlock(BlockManager.java:1547)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getNewBlockTargets(FSNamesystem.java:3107)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock(FSNamesystem.java:3031)
at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.addBlock(NameNodeRpcServer.java:724)
at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.addBlock(ClientNamenodeProtocolServerSideTranslatorPB.java:492)
at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:616)
at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:969)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2049)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2045)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:415)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1657)
at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2043)
at org.apache.hadoop.ipc.Client.call(Client.java:1475)
at org.apache.hadoop.ipc.Client.call(Client.java:1412)
at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:229)
at com.sun.proxy.$Proxy9.addBlock(Unknown Source)
at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.addBlock(ClientNamenodeProtocolTranslatorPB.java:418)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:191)
at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:102)
at com.sun.proxy.$Proxy10.addBlock(Unknown Source)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.locateFollowingBlock(DFSOutputStream.java:1459)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.nextBlockOutputStream(DFSOutputStream.java:1255)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.run(DFSOutputStream.java:449)
put: File /names/node_setup._COPYING_ could only be replicated to 0 nodes instead of minReplication (=1). There are 3 datanode(s) running and 3 node(s) are excluded in this operation.
[[email protected] hadoop]$
inner Reply to inner to inner" aria-label=' Reply to inner to inner'> Reply to inner
July 19, 2016 at 7:11 pm
Thanks for the guide! Now, I am having a problem after I incorrectly turned off the cluster of 3 datanodes. All of them now are dead, it is shown after executing a command:
./bin/hdfs dfsadmin -refreshNodes
Configured Capacity: 0 (0 B)
Present Capacity: 0 (0 B)
DFS Remaining: 0 (0 B)
DFS Used: 0 (0 B)
DFS Used%: NaN%
Under replicated blocks: 0
Blocks with corrupt replicas: 0
Missing blocks: 0
Missing blocks (with replication factor 1): 0
————————————————-
Dead datanodes (3):
Name: 192.168.0.15:50010 (datanode2)
Hostname: datanode2
Decommission Status : Normal
Configured Capacity: 0 (0 B)
DFS Used: 0 (0 B)
Non DFS Used: 0 (0 B)
DFS Remaining: 0 (0 B)
DFS Used%: 100.00%
DFS Remaining%: 0.00%
Configured Cache Capacity: 0 (0 B)
Cache Used: 0 (0 B)
Cache Remaining: 0 (0 B)
Cache Used%: 100.00%
Cache Remaining%: 0.00%
Xceivers: 0
Last contact: Thu Jan 01 01:00:00 GMT 1970
Name: 192.168.0.14:50010 (datanode1)
Hostname: datanode1
Decommission Status : Normal
Configured Capacity: 0 (0 B)
DFS Used: 0 (0 B)
Non DFS Used: 0 (0 B)
DFS Remaining: 0 (0 B)
DFS Used%: 100.00%
DFS Remaining%: 0.00%
Configured Cache Capacity: 0 (0 B)
Cache Used: 0 (0 B)
Cache Remaining: 0 (0 B)
Cache Used%: 100.00%
Cache Remaining%: 0.00%
Xceivers: 0
Last contact: Thu Jan 01 01:00:00 GMT 1970
Name: 192.168.0.16:50010 (datanode3)
Hostname: datanode3
Decommission Status : Normal
Configured Capacity: 0 (0 B)
DFS Used: 0 (0 B)
Non DFS Used: 0 (0 B)
DFS Remaining: 0 (0 B)
DFS Used%: 100.00%
DFS Remaining%: 0.00%
Configured Cache Capacity: 0 (0 B)
Cache Used: 0 (0 B)
Cache Remaining: 0 (0 B)
Cache Used%: 100.00%
Cache Remaining%: 0.00%
Xceivers: 0
Last contact: Thu Jan 01 01:00:00 GMT 1970
How do I recover the datanodes?
What I have already tried is to turn off/on again, -format command, -refreshNodes command, included all datanodes in the permitted hosts file, nothing helps.
There’s got to be a way restoring these datanodes and running them again..
Shankar Reply to Shankar to Shankar" aria-label=' Reply to Shankar to Shankar'> Reply to Shankar
June 26, 2015 at 7:18 am
Hi,
Nice Guide, I have some problem, while starting all node except datanode is not showing in jps.
What is the issue?
Please help.
Thanks in Advance
Shankar D
- Rahul Reply to Rahul to Rahul" aria-label=' Reply to Rahul to Rahul'> Reply to Rahul
  June 26, 2015 at 9:36 am
  Hi Shankar,
  Please check log files and let us know any any error is generating there.
  - Punit Bansal Reply to Punit to Punit Bansal" aria-label=' Reply to Punit to Punit Bansal'> Reply to Punit
    May 8, 2017 at 5:01 am
    Hi Rahul,
    I have installed the hadoop in ubuntu 16.04 but i am not able to install the hadoop in CentOS.
    In ubuntu i am able to set the Interfaces, hostname and hosts but not able to set the these things in centos.
    Please share the some steps.
    Thanks
    Punit
Alex Reply to Alex to Alex" aria-label=' Reply to Alex to Alex'> Reply to Alex
February 19, 2015 at 10:31 am
Hi Rahul,
nice guide! I have a problem running the step number 4.
it got this error:
it is impossible to create .ssh dir
which permission should have hadoop user? in which groups should be menber?
thank you in advance for your time
Alex
Karthik Reply to Karthik to Karthik" aria-label=' Reply to Karthik to Karthik'> Reply to Karthik
September 1, 2014 at 10:35 am
Hi Rahul,
I had followed your steps for cluster installation and i successfully done it with namenode & one datanode, now i have some small doubts about how to load data into datanode directly from servers and how to get it into HDFS. plz help me with some suggestions.
And can i install hive on name node by following your HIVE article now
Singh Reply to Singh to Singh" aria-label=' Reply to Singh to Singh'> Reply to Singh
March 13, 2014 at 8:43 pm
Hey Rahul,
That was awesome clear instrauction. I was able to do this thing with little twicks for java. But I would say great article. Thanks
Kiran Reply to Kiran to Kiran" aria-label=' Reply to Kiran to Kiran'> Reply to Kiran
February 15, 2014 at 4:30 pm
Hi Rahul,
Could u send me the roles & responsibilites of Hadoop Admin and tips for Admin ?
I would need to put in my CV ..
Pls kindly help me .
Alex Reply to Alex to Alex" aria-label=' Reply to Alex to Alex'> Reply to Alex
January 21, 2014 at 2:48 pm
It is cool, what you wrote, but…. 1. Where I could verify what hadoop working? I couldn’t find any logs on slave. 2. Any examples how it is working? Like put any web sites or what?
Thanks anyway, it is working on the master.
Bill Reply to Bill to Bill" aria-label=' Reply to Bill to Bill'> Reply to Bill
November 11, 2013 at 9:05 am
Thank you Rahul!
This is excellent! Simple and clear instructions, helped me a lot!
savitha Reply to savitha to savitha" aria-label=' Reply to savitha to savitha'> Reply to savitha
September 14, 2013 at 5:16 am
Hi Rahul
I found this article useful for my work, Thank You. I hve already created a single node cluster and i am planning to do multi node, is it possible to do it in 2 laptop with same configuration and memory. if so wat are the requirements needed for hardware settings like switches,cables.
venkatrama rao Reply to venkatrama to venkatrama rao" aria-label=' Reply to venkatrama to venkatrama rao'> Reply to venkatrama
August 13, 2013 at 5:00 pm
Hi
Thanks Rahul for your nice and simple artilcle,
am followed all the steps as mentioned but my data nodes (slvae1 & slave2) are not starting
it worked in single node installation..
i dont where i messedup.., passwordless ssh is working fine and when am trying to start the services in slave1 it asking for password of [email protected]: insteadof either [email protected] or [email protected] why pls help me
Thanks in advance
Venaktrama rao
- Rahul Reply to Rahul to Rahul" aria-label=' Reply to Rahul to Rahul'> Reply to Rahul
  August 14, 2013 at 7:52 am
  Hi Venaktrama,
  You only need to start service at master server ( Step #9 ). and watch the logs on slave servers.