Installation step:

1) JDK - Hadoop is written in Java, the program does not install the Java virtual machine how to run the Hadoop;

2) create a user specifically for linux and run hadoop perform tasks (such as map and reduce task), just under the windows service accounts, and authorizing him to have access to running JDK directory permissions, so that he can perform the java virtual machine. Finally, this account is used to run the bin .start_all.sh start all services hadoop, that account must have run him, he must have sufficient permissions. Furthermore, we need to configure the environment variable personal account, the home directory of the Java virtual machine environment variables one address, or run behind hadoop task is certainly being given, could not find the java command to run in the current environment variables.

2) modify / etc / hosts file and / etc / hostname - clustered mode machine needs to communicate with each other, by the IP address. And usually we use a host name, and then to the target host communication by mapping IP addresses and host names. Then we naturally have to change the / etc / hosts file and / etc / hostname, the former is the mapping between the host and the IP address, which is the local host names;

4) SSH - between the cluster machine to access each other's resources need to establish a connection, using the SSH protocol is a secure channel for data exchange, moreover also need to use the SSH authorized certificate approach to achieve the target host password Free;

4) and it is to install a hadoop. We need to modify a few configuration files. hadoop configuration file there are many.

read-only configuration file: src / core / core-default.xml, src / hdfs / hdfs-default.xml, src / mapred / mapred-default.xml, conf / mapred-queues.xml.

Location settings: conf / core-site.xml, conf / hdfs-site.xml, conf / mapred-site.xml, conf / mapred-queues.xml. Such documents are generally used to configure hadoop some core features such hdfs mapred and directory information.

environment configuration: conf / Hadoop-env.sh

Back to the topic, since the core hadoop is hdfs and mapreduce, you at least want to configure hdfs of namenode directory location, datanode directory location, mapreduce the job tracker and task tracker port number, the system directory and the local directory to-peer communication Wait.

The master and slave on the machine are the same.

5) After the configuration is to format the hdfs. Formatting hdfs system on the master machine.

6) End hdfs formatting system start all hdfs process.

built environment using VMWare Workstation 12. Here with three Linux virtual machine: master, slave1, slave2.

Specific configuration:

be installed on the master machine JDK and SSH

1. JDK installation

jerry @ ubuntu: / run / network $ scp jerry@192.168.2.100: /home/jerry/Download/jdk-8u65-linux-x64.tar.gz ~
The authenticity of host '192.168.2.100 (192.168.2.100) 'can not be established
ECDSA key fingerprint is da:. b7: c3: 2a: ea: a2: 76: 4c: c3: c1: 68: ca: 0e: c2: ea: 92.
Are you sure you want to continue connecting (yes / no) yes
Warning:? Permanently added '192.168.2.100' (ECDSA) to the list of known hosts
jerry @. 192.168.2.100's password:
scp: /home/jerry/Download/jdk-8u65-linux-x64.tar.gz: No such file or directory
jerry @ ubuntu: / run / network $ scp jerry@192.168.2.100: /home/jerry/Downloads/jdk-8u65-linux-x64.tar.gz ~
jerry@192.168.2.100's password:
jdk-8u65-linux-x64 .tar.gz                     100%   173MB   21.6MB / s   00: 08    
jerry @ ubuntu: / run / network $ cd ~
jerry @ ubuntu: ~ $ ls
Desktop     Downloads         jdk-8u65-linux-x64.tar.gz   Pictures   Templates
Documents   examples.desktop   Music                       Public     Videos
jerry @ ubuntu:. ~ $ cd
jerry @ ubuntu: ~ $ cd /
jerry @ ubuntu: / $ ls
bin     dev   initrd.img   lost + found   opt   run   sys   var
boot   etc   lib         media       proc   sbin   tmp   vmlinuz
cdrom   home   lib64       mnt         root   srv   usr
jerry @ ubuntu: / $ sudo mkdir jvm
[sudo] password for jerry:
jerry @ ubuntu: / $ rm jvm /
rm: can not remove ‘ jvm / ’: Is a directory
jerry @ ubuntu: / $ rm -d jvm /
rm: remove write-protected directory ‘ jvm / ’? y
rm: can not remove ‘ jvm / ’: Permission denied
jerry @ ubuntu: / $ ls
bin     dev   initrd.img   lib64       mnt   root   srv   usr
boot   etc   jvm         lost + found   opt   run   sys   var
cdrom   home   lib         media       proc   sbin   tmp   vmlinuz
jerry @ ubuntu: / $ sudo mkdir / usr / lib / jvm
jerry @ ubuntu: / $ cd ~
jerry @ ubuntu: ~ $ sudo tar zxf ./jdk-8u65-linux -x64.tar.gz -C / usr / lib / jvm /
jerry @ ubuntu: ~ $ cd / usr / lib / jvm /
jerry @ ubuntu: / usr / lib / jvm $ sudo mv jdk1.8.0_65 java
jerry @ ubuntu: / usr / lib / jvm $ cd java /
jerry @ ubuntu: / usr / lib / jvm / java $ sudo vim ~ / .bashrc
jerry @ ubuntu: / usr / lib / jvm / java $ tail -n 4 ~ / .bashrc
export JAVA_HOME = / usr / lib / jvm / java
export JRE_HOME = $ {JAVA_HOME} / jre  
export CLASSPATH =: $ {JAVA_HOME} / lib:. $ {JRE_HOME} / lib  
export PATH = $ {JAVA_HOME} / bin: $ PATH
jerry @ ubuntu: / usr / lib / jvm / java $ java -version
The program 'java' can be found in the following packages:
  * default-jre
  * gcj-4.8-jre-headless
  * openjdk-7-jre-headless
  * gcj-4.6-jre-headless
  * openjdk-6-jre-headless
Try: sudo apt -get install < selected package >
jerry @ ubuntu: / usr / lib / jvm / java $ sudo update-alternatives --install / usr / bin / java java / usr / lib / jvm / java / bin / java 300
update-alternatives: using / usr / lib / jvm / java / bin / java to provide / usr / bin / java (java) in auto mode
jerry @ ubuntu: / usr / lib / jvm / java $ sudo update-alternatives --install / usr / bin / javac javac / usr / lib / jvm / java / bin / javac 300
update-alternatives: using / usr / lib / jvm / java / bin / javac to provide / usr / bin / javac (javac) in auto mode
jerry @ ubuntu: / usr / lib / jvm / java $ sudo update-alternatives --install / usr / bin / jar jar / usr / lib / jvm / java / bin / jar 300
update-alternatives: using / usr / lib / jvm / java / bin / jar to provide / usr / bin / jar (jar) in auto mode
jerry @ubuntu: / usr / lib / jvm / java $ sudo update-alternatives --install / usr / bin / javah javah / usr / lib / jvm / java / bin / javah 300
update-alternatives: using / usr / lib / jvm / java / bin / javah to provide / usr / bin / javah (javah) in auto mode
jerry @ ubuntu: / usr / lib / jvm / java $ sudo update-alternatives --install / usr / bin / javap javap / usr / lib / jvm / java / bin / javap 300
update-alternatives: using / usr / lib / jvm / java / bin / javap to provide / usr / bin / javap (javap) in auto mode
jerry @ ubuntu: / usr / lib / jvm / java $ sudo update-alternatives --config java
There is only one alternative in link group java (providing / usr / bin / java) : / usr / lib / jvm / java / bin / java
Nothing to configure
jerry @ ubuntu:. / usr / lib / jvm / java $ java -version
java version "1.8. 0_65 "
Java (TM) SE Runtime Environment (build 1.8.0_65-b17)
Java HotSpot (TM) 64-Bit Server VM (build 25.65-b01, mixed mode)
jerry @ ubuntu: / usr / lib / jvm / java $

 . 2 hadoop add users and groups

jerry @ ubuntu: / usr / lib / jvm / java $ sudo groupadd hadoop
[sudo] password for jerry:
jerry @ ubuntu: / usr / lib / jvm / java $ useradd hadoop - g hadoop
useradd: Permission denied
useradd:. can not lock / etc / passwd; try again later
jerry @ ubuntu:. / usr / lib / jvm / java $ sudo useradd hadoop -g hadoop
jerry @ ubuntu: / usr / lib / jvm / java $

3. Modify / etc / hosts file configuration master, slave1, slave2 host IP address and host name mappings. Modify / etc / hostname file to configure local computer name.

jerry @ ubuntu: ~ $ cat / etc / hosts
127.0.0.1     localhost
127.0.1.1     master

# 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
master 192.168.2.110
slave1 192.168.2.111
slave2 192.168.2.112    
jerry @ ubuntu: ~ $ cat / etc / hostname
master
jerry @ ubuntu: ~ $

4. Installing SSH

jerry @ ubuntu: / usr / lib / jvm / java $ sudo apt-get install ssh
Reading package lists ... Done
Building dependency tree      
Reading state information ... Done
The following extra packages will be installed:
  libck-connector0 ncurses-term openssh-client openssh-server
  openssh-sftp-server ssh-import -id
Suggested packages:
  libpam-ssh keychain monkeysphere rssh molly-guard
The following NEW packages will be installed:
  libck-connector0 ncurses-term openssh- server openssh-sftp-server ssh
  ssh-import-id
The following packages will be upgraded:
  openssh-client
1 upgraded, 6 newly installed, 0 to remove and 239 not upgraded.
Need to get 617 kB / 1,181 kB of archives.
After this operation, 3,450 kB of additional disk space will be used.
Do you want to continue? [Y / n] Y
Get: 1 http://us.archive.ubuntu.com/ubuntu/ trusty / main libck-connector0 amd64 0.4.5-3.1ubuntu2 [10.5 kB]
Get: 2 http://us.archive.ubuntu.com/ubuntu/ trusty / main ncurses-term all 5.9 + 20140118-1ubuntu1 [243 kB]
Get: 3 http://us.archive.ubuntu.com/ ubuntu / trusty-updates / main openssh-sftp-server amd64 1: 6.6p1-2ubuntu2.3 [34.1 kB]
Get: 4 http://us.archive.ubuntu.com/ubuntu/ trusty-updates / main openssh-server amd64 1: 6.6p1-2ubuntu2.3 [319 kB]
Get: 5 http://us.archive.ubuntu.com/ubuntu/ trusty-updates / main ssh all 1: 6.6p1- 2ubuntu2.3 [1,114 B]
Get: 6 http://us.archive.ubuntu.com/ubuntu/ trusty / main ssh-import-id all 3.21-0ubuntu1 [9,624 B]
fetched 617 kB in 16s (37.3 kB / s)                                              
Preconfiguring packages ...
Selecting previously unselected package libck-connector0: amd64
(Reading database ... 166519 files and directories currently installed.)
. Preparing to unpack ... / libck-connector0_0.4.5-3.1ubuntu2_amd64.deb ...
Unpacking libck-connector0: amd64 (0.4.5-3.1ubuntu2) ...
Preparing to unpack .. ./openssh-client_1%3a6.6p1-2ubuntu2.3_amd64.deb ...
Unpacking openssh-client (1: 6.6p1-2ubuntu2.3) over (1: 6.6p1-2ubuntu2) ...
Selecting previously unselected package ncurses-term.
Preparing to unpack ... / ncurses-term_5.9 + 20140118-1ubuntu1_all.deb ...
Unpacking ncurses-term (5.9 + 20140118-1ubuntu1) ...
Selecting previously unselected package openssh-sftp-server.
Preparing to unpack ... / openssh-sftp-server_1% 3a6.6p1-2ubuntu2.3_amd64.deb ...
Unpacking openssh-sftp-server. (1: 6.6p1-2ubuntu2.3) ...
Selecting previously unselected package openssh-server
Preparing to unpack ... / openssh-server_1% 3a6.6p1- 2ubuntu2.3_amd64.deb ...
Unpacking openssh-server (1: 6.6p1-2ubuntu2.3) ...
Selecting previously unselected package ssh
Preparing to unpack ... /. ssh_1% 3a6.6p1-2ubuntu2.3_all.deb ...
Unpacking ssh (1: 6.6p1-2ubuntu2.3) ...
Selecting previously unselected package ssh-import-id
Preparing to unpack ... / ssh-import-id_3.21-0ubuntu1_all.deb ...
Unpacking ssh-import-id (3.21-0ubuntu1) ...
Processing triggers for man-db (2.6.7.1-1ubuntu1) ...
Processing triggers for ureadahead (0.100.0-16) ...
ureadahead will be reprofiled on next reboot
Processing triggers for ufw (0.34 ~ rc-0ubuntu2) ...
Setting up libck-connector0: amd64 (0.4.5-3.1ubuntu2) ...
Setting up openssh-client (1: 6.6p1-2ubuntu2.3) .. .
Setting up ncurses-term (5.9 + 20140118-1ubuntu1) ...
Setting up openssh-sftp-server (1: 6.6p1-2ubuntu2.3) ...
Setting up openssh-server (1: 6.6p1-2ubuntu2.3) ...
Creating SSH2 RSA key; this may take some time ...
Creating SSH2 DSA key; this may take some time ...
Creating SSH2 ECDSA key; this may take some time ...
Creating SSH2 ED25519 key; this may take some time ...
ssh start / running, process 7611
Setting up ssh-import-id (3.21-0ubuntu1) ...
Processing triggers for ureadahead (0.100.0-16) ...
Processing triggers for ufw (0.34 ~ rc-0ubuntu2) ...
Setting up ssh (1: 6.6p1-2ubuntu2.3) ...
Processing triggers for libc-bin (2.19-0ubuntu6.6) ...

5. Decompression hadoop archive locally, modify the configuration file

jerry @ ubuntu: ~ $ sudo tar zxf hadoop-1.2.1.tar.gz -C / opt /
[sudo] password for jerry:
jerry @ ubuntu: ~ $ cd / opt /hadoop-1.2.1/
jerry @ ubuntu: /opt/hadoop-1.2.1$ ls
bin           hadoop-ant-1.2.1.jar           ivy           sbin
build.xml     hadoop-client-1.2.1.jar       ivy.xml       share
c ++           hadoop-core-1.2.1.jar         lib           src
CHANGES .txt   hadoop-examples-1.2.1.jar     libexec       webapps
conf         hadoop-minicluster-1.2.1.jar   LICENSE.txt
contrib       hadoop-test-1.2.1.jar         NOTICE.txt
docs         hadoop-tools-1.2.1.jar         README.txt
jerry @ ubuntu: /opt/hadoop-1.2.1$ cd conf /
jerry @ ubuntu: /opt/hadoop-1.2.1/conf$ ls
capacity-scheduler.xml       hadoop-policy.xml       slaves
configuration.xsl           hdfs-site.xml           ssl-client.xml.example
core-site.xml               log4j.properties       ssl-server.xml.example
fair-scheduler.xml           mapred-queue-acls.xml   taskcontroller.cfg
hadoop-env.sh               mapred-site .xml         task-log4j.properties
hadoop-metrics2.properties   masters
jerry @ ubuntu: /opt/hadoop-1.2.1/conf$ vim hadoop-env.sh
jerry @ ubuntu: /opt/hadoop-1.2.1/conf$ sudo vim hadoop-env.sh
jerry @ ubuntu: /opt/hadoop-1.2.1/conf$ tail -n 1 hadoop -env.sh
export JAVA_HOME = / usr / lib / jvm / java
jerry @ ubuntu: /opt/hadoop-1.2.1/conf$ sudo vim core-site.xml
jerry @ubuntu: /opt/hadoop-1.2.1/conf$ cat 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: // master: 9000 < / value >
    < / property >
    < property >
        < name > hadoop.tmp.dir < / name >
        < value > / hadoop / hadooptmp < / value >
    < / property >
< / configuration >
jerry @ ubuntu: /opt/hadoop-1.2.1/conf$ sudo vim hdfs-site.xml
jerry @ ubuntu :? /opt/hadoop-1.2.1/conf$ cat 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 >
    < / property >
    < property >
        < name > dfs.name.dir < / name >
        < value > / hadoop / hdfs / name < / value >
    < / property >
    < property >
        < name > dfs.data.dir < / name >
        < value > / hadoop / hdfs / data < / value >
    < / property >
< / configuration >
jerry @ ubuntu: / opt / hadoop- 1.2.1 / conf $ sudo vim mapred-
jerry @ ubuntu: /opt/hadoop-1.2.1/conf$ sudo vim mapred-site.xml
jerry @ ubuntu: /opt/hadoop-1.2 .1 / conf $ cat mapred-site.xml
?

< -! Put site-specific property overrides in this file - >.

< configuration >
< property >
< name > mapred.job.tracker < / name >
< value > master: 9001 < / value >
< / property >
< / configuration >
jerry @ ubuntu: /opt/hadoop-1.2.1/conf$ sudo vim mapred-site.xml
jerry @ ubuntu: / opt / hadoop-1.2.1 / conf $ cat mapred-site.xml
?
?

< -! Put site-specific property overrides in this file - >.

< configuration >
< property >
    < name > mapred.job.tracker < / name >
    < value > master: 9001 < / value >
< / property >
< property >
    < name > mapred.system.dir < / name >  
    < value > / hadoop / mapred / mapred_system < / value >
< / property >
< property >
    < name > mapred.local. dir < / name >  
    < value > / hadoop / mapred / mapred_local < / value >
< / property >
< / configuration >
jerry @ ubuntu: /opt/hadoop-1.2.1/conf$ ls
capacity-scheduler.xml       hadoop-policy.xml       slaves
configuration.xsl           hdfs-site.xml           ssl-client.xml.example
core-site.xml               log4j.properties       ssl-server.xml.example
fair-scheduler.xml           mapred-queue-acls.xml   taskcontroller.cfg
hadoop -env.sh               mapred-site.xml         task-log4j.properties
hadoop-metrics2.properties   masters
jerry @ubuntu: /opt/hadoop-1.2.1/conf$ sudo vim masters
jerry @ ubuntu: /opt/hadoop-1.2.1/conf$ sudo vim slaves
jerry @ ubuntu: / opt / hadoop-1.2.1 / conf $ cat masters
master
jerry @ ubuntu: /opt/hadoop-1.2.1/conf$ cat slaves
master
slave1
slave2
jerry @ ubuntu: /opt/hadoop-1.2.1/conf $

.ssh file is created under the master, slave1 and slave2 of hadoop user directory folder

jerry @ slave1: ~ $ sudo mkdir -p / hadoop / hdfs / name
[sudo] password for jerry:
jerry @ slave1: ~ $ sudo mkdir -p / hadoop / hdfs / data
jerry @ slave1: ~ $ sudo mkdir -p / hadoop / mapred / mapred_system
jerry @ slave1: ~ $ sudo mkdir -p / hadoop / mapred / mapred_local
jerry @ slave1: ~ $ sudo mkdir -p / hadoop / hadooptmp
jerry @ slave1: ~ $ chown -R hadoop: hadoop / hadoop /
chown: changing ownership of ‘ / hadoop / mapred / mapred_local ’: Operation not permitted
chown: changing ownership of ‘ / hadoop / mapred / mapred_system ’: Operation not permitted
chown: changing ownership of ‘ / hadoop / mapred ’: Operation not permitted
chown: changing ownership of ‘ / hadoop / hdfs / data ’: Operation not permitted
chown: changing ownership of ‘ / hadoop / hdfs / name ’: Operation not permitted
chown: changing ownership of ‘ / hadoop / hdfs ’: Operation not permitted
chown: changing ownership of ‘ / hadoop / hadooptmp ’: Operation not permitted
chown: changing ownership of ‘ / hadoop / ’: Operation not permitted
jerry @ slave1: ~ $ sudo chown -R hadoop: hadoop / hadoop /
jerry @ slave1: ~ $

On the master secret key survival ssh then copied to the .ssh directory hadoop user's home directory on slave1 and slave2 under

hadoop @ master: ~ $ sudo mkdir ~ / .ssh
[sudo] password for hadoop:
hadoop @ master: ~ $ sudo chown -R hadoop: hadoop   ~ / .ssh
hadoop @ master: ~ $ ssh-keygen -t rsa -P '' -f ~ / .ssh / id_rsa
Generating public / private rsa key pair
Your identification has been saved in / home. . /hadoop/.ssh/id_rsa
Your public key has been saved in /home/hadoop/.ssh/id_rsa.pub
The key fingerprint is:.
36: 99: e0: e9: aa: b8: c3: c6: cd: 97: 59: 9f: 49: 87: 0d: bf hadoop @ master
The key's randomart image is:
+ - [RSA 2048] - --- +
|                 |
|                 |
|  .               |
|     o +       |.
|       o S =       |
|  .   o + +     |
| o o  . = o +     |
. | = o =   + E     |
| + o..o             |
+ ---------- ------- +
hadoop @ master: ~ / .ssh $ scp authorized_keys slave1: /home/hadoop/.ssh
The authenticity of host 'slave1 (192.168.2.111)' can ' t be established
ECDSA key fingerprint is 48:. 93: 30: 0d: bb: 3a: 85: da: 46: 3f: 75: 76: 3e: b7: 42:. 6a
Are you sure you want to continue connecting (yes / no) yes
Warning:? Permanently added 'slave1,192.168.2.111' (ECDSA) to the list of known hosts
hadoop @ slave1's password:.
scp: /home/hadoop/.ssh/authorized_keys: Permission denied
hadoop @ master: ~ / .ssh $ scp authorized_keys slave1: /home/hadoop/.ssh
hadoop @ slave1's password:
authorized_keys                               100%   395     0.4KB / s   00: 00    
hadoop @ master: ~ / .ssh $ scp authorized_keys slave2: /home/hadoop/.ssh
The authenticity of host 'slave2 (192.168.2.112)' can not be established
ECDSA key fingerprint is 48: 93: 30: 0d: bb: 3a: 85: da: 46: 3f: 75: 76: 3e: b7: 42: 6a
Are you sure you want to continue connecting (. ?. yes / no) yes
Warning: Permanently added 'slave2,192.168.2.112' (ECDSA) to the list of known hosts
hadoop @ slave2's password:
authorized_keys                               100%   395     0.4KB / s   00: 00    
hadoop @ master : ~ / .ssh $

then test again at whether ssh connection when you need to type a password. The result is not required.

hadoop @ master: ~ / .ssh $ ssh slave1
Welcome to Ubuntu 14.04.3 LTS (GNU / Linux 3.19.0-42-generic x86_64)

  * Documentation:   https://help.ubuntu.com/

0 packages can be updated.
0 updates are security updates.

$ ls -al
total 239436
drwxr-xr-x 12 hadoop hadoop       4096 Jan  . 9 22:37
drwxr-xr-x   4 root   root         4096 Jan   9 22:25 ..
drwx ------   2 hadoop hadoop       4096 Jan   9 22:37 .cache
drwxr-xr-x   2 hadoop hadoop       4096 Dec 27 04:19 Desktop
drwxr-xr-x   2 hadoop hadoop       4096 Dec 27 04:19 Documents
drwxr-xr-x   2 hadoop hadoop       4096 Dec 27 04:19 Downloads
-rw-r - r -   1 hadoop hadoop       8980 Dec 27 03 : 27 examples.desktop
-rw-rw-r -   1 hadoop hadoop   63851630 Dec 30 05:25 hadoop-1.2.1.tar.gz
-rw-rw-r--   1 hadoop hadoop 181260798 Dec 27 06:49 jdk-8u65-linux-x64.tar.gz
drwxr-xr-x   2 hadoop hadoop       4096 Dec 27 04:19 Music
drwxr-xr-x   2 hadoop hadoop       4096 Dec 27 04:19 Pictures
drwxr-xr-x   2 hadoop hadoop       4096 Dec 27 04:19 Public
drwxr-xr-x   2 hadoop hadoop       4096 Jan   9 22:39 .ssh
drwxr-xr-x   2 hadoop hadoop       4096 Dec 27 04:19 Templates
drwxr-xr-x   2 hadoop hadoop       4096 Dec 27 04:19 Videos
$

hadoop @ master: ~ / .ssh $ ssh slave2
Welcome to Ubuntu 14.04.3 LTS (GNU / Linux 3.19.0-42-generic x86_64)

  * Documentation:   https://help.ubuntu.com/

27 packages can be updated.
23 updates are security updates.

$ ls -l
total 239424
drwxr-xr-x 2 hadoop hadoop       4096 Dec 27 04:19 Desktop
drwxr-xr-x 2 hadoop hadoop       4096 Dec 27 04:19 Documents
drwxr-xr-x 2 hadoop hadoop       4096 Dec 27 04:19 Downloads
-rw-r - r-- 1 hadoop hadoop       8980 Dec 27 03:27 examples.desktop
-rw-rw-r-- 1 hadoop hadoop   63851630 Dec 30 05:25 hadoop-1.2.1.tar.gz
-rw-rw-r-- 1 hadoop hadoop 181260798 Dec 27 06:49 jdk-8u65-linux-x64.tar.gz
drwxr-xr-x 2 hadoop hadoop       4096 Dec 27 04: 19 Music
drwxr-xr-x 2 hadoop hadoop       4096 Dec 27 04:19 Pictures
drwxr-xr-x 2 hadoop hadoop       4096 Dec 27 04:19 Public
drwxr-xr-x 2 hadoop hadoop       4096 Dec 27 04:19 Templates
drwxr-xr-x 2 hadoop hadoop       4096 Dec 27 04:19 Videos
$ exit
Connection to slave2 closed
hadoop @ master:. ~ / .ssh $

Format hdfs of namenode

hadoop @ master: /opt/hadoop-1.2.1/bin$ ./hadoop namenode -format16 / 01/09 23:33:18 INFO namenode.NameNode: STARTUP_MSG:
/ ***** ************************************************** *****
STARTUP_MSG: Starting NameNode
STARTUP_MSG:   host = master / 127.0.1.1
STARTUP_MSG:   args = [-format]
STARTUP_MSG:   version = 1.2.1
STARTUP_MSG:   build = https://svn.apache.org/repos/asf/hadoop/common/branches/branch-1.2 -r 1503152; compiled by 'mattf' on Mon Jul 22 15:23:09 PDT 2013
STARTUP_MSG:   java = 1.8.0_65
************************* *********************************** /
Re-format filesystem in / hadoop / hdfs / ? name (Y or N) Y
16/01/09 23:34:09 INFO util.GSet: Computing capacity for map BlocksMap
16/01/09 23:34:09 INFO util.GSet : VM type       = 64-bit
16/01/09 23:34:09 INFO util.GSet: 2.0% max memory = 1013645312
16/01/09 23:34: 09 INFO util.GSet: capacity       = 2 ^ 21 = 2097152 entries
16/01/09 23:34:09 INFO util.GSet: recommended = 2097152, actual = 2097152
16 / 01/09 23:34:10 INFO namenode.FSNamesystem: fsOwner = hadoop
16/01/09 23:34:10 INFO namenode.FSNamesystem: supergroup = supergroup
16/01/09 23: 34:10 INFO namenode.FSNamesystem: isPermissionEnabled = true
16/01/09 23:34:10 INFO namenode.FSNamesystem: dfs.block.invalidate.limit = 100
16/01/09 23: 34:10 INFO namenode.FSNamesystem: isAccessTokenEnabled = false accessKeyUpdateInterval = 0 min (s), accessTokenLifetime = 0 min (s)
16/01/09 23:34:10 INFO namenode.FSEditLog: dfs.namenode.edits .toleration.length = 0
16/01/09 23:34:10 INFO namenode.NameNode: Caching file names occuring more than 10 times
16/01/09 23:34:11 INFO common. Storage: Image file / hadoop / hdfs / name / current / fsimage of size 112 bytes saved in 0 seconds
16/01/09 23:34:11 INFO namenode.FSEditLog:. closing edit log: position = 4, editlog = / hadoop / hdfs / name / current / edits
16/01/09 23:34:11 INFO namenode.FSEditLog: close success: truncate to 4, editlog = / hadoop / hdfs / name / current / edits
16/01/09 23:34:11 INFO common.Storage: Storage directory / hadoop / hdfs / name has been successfully formatted
16/01/09 23:34:11 INFO namenode.NameNode. : SHUTDOWN_MSG:
/ ****************************************** ******************
SHUTDOWN_MSG: Shutting down NameNode at master / 127.0.1.1
************* *********************************************** /
hadoop@master:/opt/hadoop-1.2.1/bin $

start hadoop master on all services

hadoop @ master: /opt/hadoop-1.2.1/bin$ ./start-all.sh
starting namenode, logging to /opt/hadoop-1.2.1/libexec/../logs/ hadoop-hadoop-namenode-master.out
slave2: starting datanode, logging to /opt/hadoop-1.2.1/libexec/../logs/hadoop-hadoop-datanode-slave2.out
slave1 : starting datanode, logging to /opt/hadoop-1.2.1/libexec/../logs/hadoop-hadoop-datanode-slave1.out
master: starting datanode, logging to /opt/hadoop-1.2.1 /libexec/../logs/hadoop-hadoop-datanode-master.out
master: starting secondarynamenode, logging to /opt/hadoop-1.2.1/libexec/../logs/hadoop-hadoop-secondarynamenode- master.out
starting jobtracker, logging to /opt/hadoop-1.2.1/libexec/../logs/hadoop-hadoop-jobtracker-master.out
slave2: starting tasktracker, logging to / opt /hadoop-1.2.1/libexec/../logs/hadoop-hadoop-tasktracker-slave2.out
slave1: starting tasktracker, logging to /opt/hadoop-1.2.1/libexec/../logs/ hadoop-hadoop-tasktracker-slave1.out
master: starting tasktracker, logging to /opt/hadoop-1.2.1/libexec/../logs/hadoop-hadoop-tasktracker-master.out
hadoop @master: /opt/hadoop-1.2.1/bin$ jps
5088 JobTracker
5010 SecondaryNameNode
4871 DataNode
4732 NameNode
5277 Jps
5230 TaskTracker
hadoop @ master: /opt/hadoop-1.2.1/bin $

Observation slave1

hadoop @ slave1: ~ / .ssh $ jps
3669 TaskTracker
3718 Jps
3560 DataNode
hadoop @ slave1: ~ / .ssh $

Observation slave2

hadoop @ slave2: ~ $ jps
3216 Jps
2982 TaskTracker
3095 DataNode

process issues that require attention:

Since you are using hadoop hadoop user to start the service, at least that was the user of java, hadoop program has access privileges to perform it, this points to note.

Second, the user hadoop of hdfs files and mapreduce file needs to have write access to it

One problem:

hadoop @ master: / usr / lib / jvm / java / bin $ jps
The program 'jps' can be found in the following packages:
  * openjdk-7-jdk
  * openjdk-6-jdk
Ask your administrator to install one of them

obviously have been installed jdk, and environmental variables did not appear wrong path, why not find jps order? The results still have to use update-alternative command to resolve this issue