前言
通过虚拟化技术，我们可轻松的增加或删除一台虚拟机。像hadoop技术，安装，配置，运维，管理都很复杂，如果能通过虚拟化技术，降低运维成本，是多么开心的一件事啊！设想一下，如果一个人能够管理1000个hadoop节点，那么小型公司也可以随随便便构建像百度，阿里一样的强大的计算集群环境。世界也许会更奇妙！
当然，本文并不是讲一个人如何管理1000个hadoop节点。但我会介绍一种方式，通过克隆虚拟机来增加Hadoop节点。也许在大家的实践操作中，就能做出一个人运维1000个节点集群的方案。
目录
系统环境介绍
克隆虚拟机
完成2个节点的hadoop集群
一. 系统环境介绍
我延续上篇文章的系统环境，让Hadoop跑在云端系列文章 之 创建Hadoop母体虚拟机
我们已成功地创建了Hadoop母体虚拟机c1。接下来，我们要用clone的方式创建c2,c3,c4,c5 ，4台克隆虚拟机。
二. 克隆虚拟机
在host中，打开虚拟机管理软件，查看c1的状态。
~ sudo virshvirsh # listId Name State----------------------------------------------------5 server3 running6 server4 running7 d2 running8 r1 running9 server2 running18 server5 running42 c1 running
c1正在运行中，由于c2之前已经创建，我们已c3来举例说明。
创建克隆体c3
~ sudo virt-clone --connect qemu:///system -o c1 -n c3 -f /disk/sdb1/c3.imgERROR Domain with devices to clone must be paused or shutoff.
关闭c1，并重新克隆
virsh # destroy c1Domain c1 destroyed~ sudo virt-clone --connect qemu:///system -o c1 -n c3 -f /disk/sdb1/c3.imgERROR A disk path must be specified to clone '/dev/sdb5'
分区硬盘引入的错误。(无比强大的google，已经找不到对这个错误的解释了)
接下的操作：
重新启动c1，注释/etc/fstab自动挂载/dev/vdb1的操作(自行解决)
卸载给c1分配的分区硬盘/dev/sdb5
~ edit c1-->
再次创建克隆体c3
~ sudo virt-clone --connect qemu:///system -o c1 -n c3 -f /disk/sdb1/c3.imgCloning c1.img 1% [ ] 47 MB/s | 426 MB 14:14 ETACloning c1.img | 40 GB 08:18Clone 'c3' created successfully.
给克隆体c3挂载分区硬盘/dev/sdb7，并启动c3
virsh # edit c3virsh # start c3virsh # console c3Connected to domain c3Escape character is ^]Ubuntu 12.10 c1 ttyS0c1 login: cosPassword:Last login: Wed Jul 10 12:00:44 CST 2013 from 192.168.1.79 on pts/0Welcome to Ubuntu 12.10 (GNU/Linux 3.5.0-32-generic x86_64)* Documentation: https://help.ubuntu.com/New release '13.04' available.Run 'do-release-upgrade' to upgrade to it.cos@c1:~$
对克隆体c3,有几个地方需要修改：
hostname,hosts
静态IP
DNS
/dev/vdb1自动挂载
配置hadoop存储目录权限
ssh自动验证
hadoop的master,slave
1. hostname,hosts
~ sudo hostname c3~ sudo vi /etc/hostnamec3~ sudo vi /etc/hosts127.0.1.1 c3
2. 静态IP
~ sudo vi /etc/network/interfacesauto loiface lo inet loopback# The primary network interfaceauto eth0#iface eth0 inet dhcpiface eth0 inet staticaddress 192.168.1.32netmask 255.255.255.0gateway 192.168.1.1
改完IP后，我们重启一下，用ssh连接。
~ ssh cos@c3.wtmart.com~ ifconfigeth0 Link encap:Ethernet HWaddr 52:54:00:06:b2:3a inet addr:192.168.1.32 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::5054:ff:fe06:b23a/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:42 errors:0 dropped:0 overruns:0 frame:0 TX packets:33 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:6084 (6.0 KB) TX bytes:4641 (4.6 KB)lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:34 errors:0 dropped:0 overruns:0 frame:0 TX packets:34 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:2560 (2.5 KB) TX bytes:2560 (2.5 KB)
3. DNS (内网的DNS)
~ sudo vi /etc/resolv.confnameserver 192.168.1.7~ ping c1.wtmart.comPING c1.wtmart.com (192.168.1.30) 56(84) bytes of data.64 bytes from 192.168.1.30: icmp_req=1 ttl=64 time=0.485 ms64 bytes from 192.168.1.30: icmp_req=2 ttl=64 time=0.552 ms
4. /dev/vdb1自动挂载
~ sudo mount /dev/vdb1 /home/cos/hadoop~ sudo vi /etc/fstab/dev/vdb1 /home/cos/hadoop ext4 defaults 0 0~ df -hFilesystem Size Used Avail Use% Mounted on/dev/mapper/u1210-root 36G 2.4G 32G 7% /udev 2.0G 4.0K 2.0G 1% /devtmpfs 791M 224K 791M 1% /runnone 5.0M 0 5.0M 0% /run/locknone 2.0G 0 2.0G 0% /run/shmnone 100M 0 100M 0% /run/user/dev/vda1 228M 29M 188M 14% /boot/dev/vdb 148G 188M 140G 1% /home/cos/hadoop
5. 配置hadoop存储目录权限
~ sudo chown -R cos:cos hadoop/~ mkdir /home/cos/hadoop/data~ mkdir /home/cos/hadoop/tmp~ sudo chmod 755 /home/cos/hadoop/data~ sudo chmod 755 /home/cos/hadoop/tmp
6. ssh自动验证
~ rm -rf ~/.ssh/~ ssh-keygen -t rsaGenerating public/private rsa key pair.Enter file in which to save the key (/home/cos/.ssh/id_rsa):Created directory '/home/cos/.ssh'.Enter passphrase (empty for no passphrase):Enter same passphrase again:Your identification has been saved in /home/cos/.ssh/id_rsa.Your public key has been saved in /home/cos/.ssh/id_rsa.pub.The key fingerprint is:54:1f:51:5f:5c:1d:ac:8a:9d:8f:fd:da:65:7e:f9:8d cos@c3The key's randomart image is:+--[ RSA 2048]----+| . oooo*|| . . . o+|| . . . .|| . . || S o o || . + || + +|| . o.=+|| .Eo*|+-----------------+~ cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys~ cat ~/.ssh/authorized_keysssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCtIK3+hGeJQOigIN1ydDVpUzFeg/urnX2DaHhuv5ik8bGGDZWmSA+qPWAZQoZFBGqGMTshvMQeksjA2WiINbFpQCGuxSFx5a9Ad0XU8bGDFi+yYfKlp1ROZ+7Jz1+cO4tjrCX4Ncr3nZlddl6Uh/yMYU+iuRQ4Ga7GXgeYoSf7C5vQmzkYija0XNa8wFr0+aeD3hau6s8dWwsw7Dn/xVA3eMqK+4LDGH6dkn6tc6nVyNbzofXdtPOsCkwHpwozwuRBL37LYcmELe+oT/GifWf0Qp4rQD/9ObtHkhKrSW45bRH/WzvkyNxl04dKlIj26zIsh9zjMHF8o0ce+zjUl7aD cos@c3
7. hadoop的master,slave
~ cd /home/cos/toolkit/hadoop-1.0.3/conf~ vi slavesc1.wtmart.comc3.wtmart.com
三. 完成2个节点的hadoop集群
重新启动c1节点，配置2个节点的hadoop集群
~ ssh cos@c1.wtmart.com~ sudo mount /dev/vdb1 /home/cos/hadoop
配置slave
~ cd /home/cos/toolkit/hadoop-1.0.3/conf~ vi slavesc1.wtmart.comc3.wtmart.com
DNS (内网的DNS)
~ sudo vi /etc/resolv.confnameserver 192.168.1.7~ ping c3.wtmart.comPING c3.wtmart.com (192.168.1.32) 56(84) bytes of data.64 bytes from 192.168.1.32: icmp_req=1 ttl=64 time=0.673 ms64 bytes from 192.168.1.32: icmp_req=2 ttl=64 time=0.429 ms
交换ssh公钥
复制c3的authorized_keys到c1的authorized_keys
~ scp cos@c3.wtmart.com:/home/cos/.ssh/authorized_keys .~ cat authorized_keys >> /home/cos/.ssh/authorized_keys~ cat /home/cos/.ssh/authorized_keysssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCuWCgfB8qSyEpKmUwnXvWtiCbzza1oD8oM3jm3EJzBRivEC/QV3k8v8zOHt2Cf4H6hYIvYHoSMilA2Wqbh1ny/70zcIYrwFiX5QvSjbEfsj7UmvxevxjB1/5F66TRLN/PyTiw3FmPYLkxvTP8CET02D2cgAN0n+XGTXQaaBqBElQGuiOJUAIvMUl0yg3mH7eP8TRlS4qYpllh04kirSbkOm6IYRDtGsrb90ew63l6F/MpPk/H6DVGC23PnD7ZcMr7VFyCkNPNqcEBwbL8qL1Hhnf7Lvlinp3M3zVU0Aet3TjkgwvcLPX8BWmrguVdBJJ3yqcocylh0YKN9WImAhVm7 cos@c1ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDU4sIHWxuyicIwFbRpDcoegDfSaUhmaBTSFSVTd/Uk8w0fTUcERNx9bZrtuiiPsOImvsBy9hN2Au/x36Jp4hO8DFxzqTNBcfD9xcEgOzHGqH7ZC5qMqx3Poy6DzN/rk9t/+wXyNCfR4kRhrPBNiF6gMDMTRQLpKK9VnY0nQ6FvOQ407gMAsyf0Fn31sHZJLtM4/kxsSOEsSNIk1V+gbIxJv2fJ/AON0/iW1zu7inUC/+YvEuTLClnUMzqFb/xKp25XxSV6a5YzThxs58KO5JCRq2Kk/SM0GSmCSkjKImUYDDjmi1P6wbrd4mh/4frQr1DqYyPeHE4UlHXD90agw767 cos@c3
把c1的authorized_keys，再分发给c3
~ scp /home/cos/.ssh/authorized_keys cos@c3.wtmart.com:/home/cos/.ssh/authorized_keys
从c1启动hadoop集群
~ start-all.shstarting namenode, logging to /home/cos/toolkit/hadoop-1.0.3/libexec/../logs/hadoop-cos-namenode-c1.outc1.wtmart.com: Warning: $HADOOP_HOME is deprecated.c1.wtmart.com:c1.wtmart.com: starting datanode, logging to /home/cos/toolkit/hadoop-1.0.3/libexec/../logs/hadoop-cos-datanode-c1.outc3.wtmart.com: Warning: $HADOOP_HOME is deprecated.c3.wtmart.com:c3.wtmart.com: starting datanode, logging to /home/cos/toolkit/hadoop-1.0.3/libexec/../logs/hadoop-cos-datanode-c3.outc1.wtmart.com: Warning: $HADOOP_HOME is deprecated.c1.wtmart.com:c1.wtmart.com: starting secondarynamenode, logging to /home/cos/toolkit/hadoop-1.0.3/libexec/../logs/hadoop-cos-secondarynamenode-c1.outstarting jobtracker, logging to /home/cos/toolkit/hadoop-1.0.3/libexec/../logs/hadoop-cos-jobtracker-c1.outc3.wtmart.com: Warning: $HADOOP_HOME is deprecated.c3.wtmart.com:c3.wtmart.com: starting tasktracker, logging to /home/cos/toolkit/hadoop-1.0.3/libexec/../logs/hadoop-cos-tasktracker-c3.outc1.wtmart.com: Warning: $HADOOP_HOME is deprecated.c1.wtmart.com:c1.wtmart.com: starting tasktracker, logging to /home/cos/toolkit/hadoop-1.0.3/libexec/../logs/hadoop-cos-tasktracker-c1.out
查看c1的进程
~ jps8861 JobTracker8486 NameNode8750 SecondaryNameNode9123 Jps9001 TaskTracker8612 DataNode
查看c3的进程
~ jps3180 TaskTracker3074 DataNode3275 Jps
这样就建立起了，2个节点的hadoop集群。
上面是我们手动操作的过程比较复杂，接下来我们的任务就是写一个自动化的脚本完成上面的操作。
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