Ubuntu 14.04 LTE下安装Hadoop 1.2.1（集群分布式模式）

安装步骤：

1) JDK -- Hadoop是用Java写的，不安装Java虚拟机怎么运行Hadoop的程序；

2）创建专门用于运行和执行hadoop任务（比如map和reduce任务）的linux用户，就像windows下的服务账户，并且授权给他可以访问运行JDK目录权限，让他可以执行java虚拟机。这个账户最后用来运行bin\.start_all.sh启动hadoop的所有服务，那运行账户肯定是他了，他肯定要有足够的权限。再者，需要配置这个账户的个人环境变量，把Java虚拟机的主目录地址环境变量之一，不然后面运行hadoop任务肯定报错，根本在当前的环境变量下找不到要运行的java命令。

2）修改/etc/hosts文件和/etc/hostname -- 集群模式下机器需要互相通信，靠的是IP地址。而通常我们利用的是主机名称，然后通过IP地址和主机名称的映射来和目标主机通信。那么我们自然就得改/etc/hosts文件和/etc/hostname，前者是主机和IP地址的映射关系，后者是主机的本地主机名；

4）SSH -- 集群机器间互相访问各自的资源需要建立连接通讯，使用的是SSH协议进行安全通道的数据交换，再者也需要利用SSH的授权证书办法来实现免密码登陆目标主机；

4）然后就是安装hadoop了。需要修改几个配置文件。hadoop的配置文件有很多种。

只读型配置文件：src/core/core-default.xml, src/hdfs/hdfs-default.xml, src/mapred/mapred-default.xml, conf/mapred-queues.xml。

定位设置：conf/core-site.xml, conf/hdfs-site.xml, conf/mapred-site.xml, conf/mapred-queues.xml。这种文件一般用于配置hadoop一些核心功能，比如hdfs和mapred的目录信息。

环境配置：conf/Hadoop-env.sh

说回正题，既然hadoop的核心是hdfs和mapreduce，那你至少要配置hdfs的namenode目录位置，datanode的目录位置，mapreduce的job tracker和task tracker通信的端口号，系统目录和本地目录等等。

这些在master和slave机子上都是相同的。

5）配置完后就是格式化hdfs了。在master机上格式化hdfs系统。

6）格式化完hdfs系统就启动所有的hdfs进程。

搭建环境用的是VMWare Workstation 12。这里用了三台Linux虚拟机：master，slave1，slave2。

具体配置：

先在master机子上安装JDK和SSH

1. JDK安装

jerry@ubuntu:/run/network$ scp [email protected]:/home/jerry/Download/jdk-8u65-linux-x64.tar.gz ~
The authenticity of host '192.168.2.100 (192.168.2.100)' can't 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.
[email protected]'s password:
scp: /home/jerry/Download/jdk-8u65-linux-x64.tar.gz: No such file or directory
jerry@ubuntu:/run/network$ scp [email protected]:/home/jerry/Downloads/jdk-8u65-linux-x64.tar.gz ~
[email protected]'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: cannot remove ‘jvm/’: Is a directory
jerry@ubuntu:/$ rm -d jvm/
rm: remove write-protected directory ‘jvm/’? y
rm: cannot 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. 添加hadoop用户和用户组

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: cannot lock /etc/passwd; try again later.
jerry@ubuntu:/usr/lib/jvm/java$ sudo useradd hadoop -g hadoop
jerry@ubuntu:/usr/lib/jvm/java$

3. 修改/etc/hosts文件，配置master, slave1, slave2的主机IP地址和主机名的映射关系。修改/etc/hostname文件，配置本机的电脑名。

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. 安装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. 解压hadoop压缩包到本地，修改配置文件

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
<?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>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
<?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>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$

在master、slave1和slave2上的hadoop用户目录下创建好.ssh文件夹

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:~$

在master上生存ssh秘钥然后拷贝到slave1和slave2上的hadoop用户主目录下的.ssh文件目录下

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'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 '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$

再测试下是否再次ssh连接的时候需要键入密码。结果是不需要的。

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
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$ exit
Connection to slave2 closed.
hadoop@master:~/.ssh$

格式化hdfs的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$

在master上启动hadoop的所有服务

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$

观察slave1

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

观察slave2

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

过程中需要注意的问题：

你既然是用hadoop用户去启动hadoop服务的，那这个用户至少得对java、hadoop程序有访问执行权限吧，这点要注意。

其次，这个用户对hadoop的hdfs的文件和mapreduce文件都需要有写入权限吧

问题一：

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

明明都安装了jdk，而且环境变量也没有出现路径错误，为什么就是找不到jps命令呢？结果还是要用update-alternative命令来解决这个问题

hadoop@master:/usr/lib/jvm/java/bin$  sudo update-alternatives --install /usr/bin/jps jps /usr/lib/jvm/java/bin/jps 1
update-alternatives: using /usr/lib/jvm/java/bin/jps to provide /usr/bin/jps (jps) in auto mode

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