Hadoop是一个能够让用户轻松架构和使用的开源分布式计算框架，一种可靠、高效、可伸缩的方式进行数据处理。本文主要目的是为大家提供一种非常简单的方法，在阿里云上部署Hadoop集群。
通过<阿里云ROS资源编排服务>，将VPC、NAT Gateway、ECS创建和Hadoop部署过程自动化，使大家能够非常方便地部署一个Hadoop集群。本文创建的Hadoop集群包含三个节点：master.hadoop，slave1.hadoop，slave2.hadoop。
UserData中安装Hadoop四部曲
正常安装Hadoop分为四步：配置ssh无密码登录，安装Java JDK，安装配置Hadoop tar包，和启动测试集群。
1. 配置ssh无密码登录
集群中的所有主机应该可以无密码ssh登录，因此3台ECS都应该执行如下命令，保证所有的主机中临时密钥和公钥均相同，这样3台ECS就可以无密码登录了。
"ssh-keygen -t rsa -P '' -f '/root/.ssh/id_rsa' \n","cd /root/.ssh \n","mv id_rsa bak.id_rsa \n","mv id_rsa.pub bak.id_rsa.pub \n","echo '-----BEGIN RSA PRIVATE KEY-----' > id_rsa \n","echo 'MIIEowIBAAKCAQEAzfQ/QHwWB1njU9+Wu3RYi9g+g5rydSpAE0klefTJuZjtcaic' >> id_rsa \n","echo 'SCeBN5avih8UToZ148+Ef2YzOtoosqluZpoYLCPSpAqr8pmviBJIU3vfu9mnDG9L' >> id_rsa \n","echo 'oevT6K8w3wCBRCmqu+vc0Tpju/EeCuYK3+8w7e2I6F3+zIYzhhX3qmkocje7ACnV' >> id_rsa \n","echo 'yh2DB/2m3sogTMc0RT+5y3kJAnC6TOIlGsYjOOkPbEF3Ifn1o4ZjOFOmQlcRJer4' >> id_rsa \n","echo '1E6rTdXAxS2uDNMFBCf9Xyx7O9J+ELTCAXc4h7AE6WLdQb5Apzv4t1KswCAtRenP' >> id_rsa \n","echo '1xGcUYY8I/JUT2VvBWtQJennrk9jrPZUFDcmcwIDAQABAoIBAAwzDZQaRYvF7UtI' >> id_rsa \n","echo 'kTslVyFhe8J76SS7jfQWfxvMPi66OkZjQG6duG+8g0VhNei42j7WSfjp6trvlT2P' >> id_rsa \n","echo '/7QgKJJkxNNmtmy2Ycljm9kmG0ibSePYq9g5ieHcjr6G3yFUfoKHJBtYpBO74pWu' >> id_rsa \n","echo 'rrI5DuLpERUCjFc9E8w7fOIhPH4XZ6wk/EmPxHTgxZk+aMvqptyPSbUyiUOvCiZf' >> id_rsa \n","echo 'MD0ircs9vgtslMVDlz9m6CoiNz6B3Yf6eLRoGGMiGnsQzZHIfnHCMX8i65Jc+TvQ' >> id_rsa \n","echo 'fLopIHzwBwI55xpcOIBRgYiEAQJhLsSNSFugoxMcwe9RalTGGS21HOQu4b3ZylKM' >> id_rsa \n","echo '8ofEVKECgYEA/Y4MzN04wAsM1yNuHN+9sdiVLG28LWH3dgpcXqa9gyNsWs9Gf8uf' >> id_rsa \n","echo 'qbuvQGeKDRXCW93wO1jO+pCYVrkyY3l+KhBKIqmkJT5gFsa8dBUvEBLALiHNg3+o' >> id_rsa \n","echo 'jR2Vqsemk8kMZA8zfJ3FKcMb1pt4S2GqepqsdC3DgzIIsxufCh7jSzsCgYEAz/Cv' >> id_rsa \n","echo 'Z7gAdSFC8q6QxFxSyhfZwGA6QW6ZU7rZv9ZdGySvZg+vHbpNVmQ0BAQzJui3Qs9u' >> id_rsa \n","echo 'XQMpYafXWzKsPzG6ZWvYXTF7fuxlovvG8Qd2A2QnGtGMB9YtQMHVqbsUDwxMjiTn' >> id_rsa \n","echo 'VBZILkDf+WCwQ98P5UMoumI0goIcNZ+AXhcqrikCgYBkSwLvKfYfqH9Mvfv5Odsr' >> id_rsa \n","echo '9NKUv1c20FB1BYYh/mxp6eIbTW/CbwXZup6IqCvoHxpBAlna77b3T6iibSDsTgtE' >> id_rsa \n","echo 'kirw6Q8/mBukBrpWZGa4QeJ4nPBQuncuUmx4H/7Y6CaZkZW5DiMF8OIbEmYT0y7+' >> id_rsa \n","echo 'zh222r9CLtFYH23aL/uSLwKBgQCS1xyG2eE41aw5RBznDWtJW15iA5If8sJD5ocu' >> id_rsa \n","echo 'eWp2aImUQS8ghxdmEozI6U5WA7CmdWUyObFXTPc/Z6FLXwqJ5IZ+CRt0neuIFNSA' >> id_rsa \n","echo 'EQy9iFQ1FBUW06BRQpBns7yOg9jr6BOTxchjIV0I9caDp1nKRIrWU9NQ9iCFnYVA' >> id_rsa \n","echo '7IsvQQKBgFxgF7UOhwaiMb/ATSuhm2v9kVvRPEO9umdo7YJ9I4L09lYbAtpcnusQ' >> id_rsa \n","echo 'fIROYL25VeEMgYcQyInc3Fm/sgJdbXQnUy+3QbbCcBCmcLj27LPQyxuu7p9hbPPT' >> id_rsa \n","echo 'Mxx37OmYvOkSVTQz0T9HfDGvOJgt4t4cXD4T/7ewk62p6jdpSQrt' >> id_rsa \n","echo '-----END RSA PRIVATE KEY-----' >> id_rsa \n","echo 'ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDN9D9AfBYHWeNT35a7dFiL2D6DmvJ1KkATSSV59Mm5mO1xqJxIJ4E3lq+KHxROhnXjz4R/ZjM62iiyqW5mmhgsI9KkCqvyma+IEkhTe9+72acMb0uh69PorzDfAIFEKaq769zROmO78R4K5grf7zDt7YjoXf7MhjOGFfeqaShyN7sAKdXKHYMH/abeyiBMxzRFP7nLeQkCcLpM4iUaxiM46Q9sQXch+fWjhmM4U6ZCVxEl6vjUTqtN1cDFLa4M0wUEJ/1fLHs70n4QtMIBdziHsATpYt1BvkCnO/i3UqzAIC1F6c/XEZxRhjwj8lRPZW8Fa1Al6eeuT2Os9lQUNyZz root@iZ2zee53wf4ndvajz30cdvZ' > id_rsa.pub \n","cp id_rsa.pub authorized_keys \n","chmod 600 authorized_keys \n","chmod 600 id_rsa \n","sed -i 's/# StrictHostKeyChecking ask/StrictHostKeyChecking no/' /etc/ssh/ssh_config \n","sed -i 's/GSSAPIAuthentication yes/GSSAPIAuthentication no/' /etc/ssh/ssh_config \n","service sshd restart \n",
为了保证安全，防止对外泄露密钥和公钥。我们要在master上执行下述命令，替换掉公开的临时密钥与公钥：
"scp -r /root/.ssh/bak.* root@$ipaddr_slave1:/root/.ssh/ \n","scp -r /root/.ssh/bak.* root@$ipaddr_slave2:/root/.ssh/ \n","ssh root@$ipaddr_slave1 \"cd /root/.ssh; rm -f id_rsa; mv bak.id_rsa id_rsa; rm -f id_rsa.pub; mv bak.id_rsa.pub id_rsa.pub; rm -f authorized_keys; cp id_rsa.pub authorized_keys; chmod 600 authorized_keys; chmod 600 id_rsa; exit\" \n","ssh root@$ipaddr_slave2 \"cd /root/.ssh; rm id_rsa; mv bak.id_rsa id_rsa; rm id_rsa.pub; mv bak.id_rsa.pub id_rsa.pub; rm authorized_keys; cp id_rsa.pub authorized_keys; chmod 600 authorized_keys; chmod 600 id_rsa; exit\" \n","cd /root/.ssh \n rm id_rsa \n mv bak.id_rsa id_rsa \n rm id_rsa.pub \n mv bak.id_rsa.pub id_rsa.pub \n rm authorized_keys \n cp id_rsa.pub authorized_keys \n chmod 600 authorized_keys \n chmod 600 id_rsa \n cd \n",
2. 安装配置JDK
master 上安装JDK，并远程控制在slaves上安装JDK。
"yum -y install aria2 \n","aria2c --header='Cookie: oraclelicense=accept-securebackup-cookie' $JdkUrl \n","mkdir -p $JAVA_HOME \ntar zxvf jdk*-x64.tar.gz -C $JAVA_HOME \ncd $JAVA_HOME \nmv jdk*.*/* ./ \nrmdir jdk*.* \n","echo >> /etc/profile \n","echo export JAVA_HOME=$JAVA_HOME >> /etc/profile \n","echo export JRE_HOME=$JAVA_HOME/jre >> /etc/profile \n","echo export CLASSPATH=$JAVA_HOME/lib:$JAVA_HOME/jre/lib:$CLASSPATH >> /etc/profile \n","echo export PATH=$JAVA_HOME/bin:$JAVA_HOME/jre/bin:$PATH >> /etc/profile \n","source /etc/profile \n","ssh root@$ipaddr_slave1 \"mkdir -p $JAVA_HOME; exit\" \n","ssh root@$ipaddr_slave2 \"mkdir -p $JAVA_HOME; exit\" \n","scp -r $JAVA_HOME/* root@$ipaddr_slave1:$JAVA_HOME \n","scp -r $JAVA_HOME/* root@$ipaddr_slave2:$JAVA_HOME \n","ssh root@$ipaddr_slave1 \"echo >> /etc/profile; echo export JAVA_HOME=$JAVA_HOME >> /etc/profile; echo export JRE_HOME=$JAVA_HOME/jre >> /etc/profile; echo export CLASSPATH=$JAVA_HOME/lib:$JAVA_HOME/jre/lib:$CLASSPATH >> /etc/profile; echo export PATH=$JAVA_HOME/bin:$JAVA_HOME/jre/bin:$PATH >> /etc/profile; source /etc/profile; exit\" \n","ssh root@$ipaddr_slave2 \"echo >> /etc/profile; echo export JAVA_HOME=$JAVA_HOME >> /etc/profile; echo export JRE_HOME=$JAVA_HOME/jre >> /etc/profile; echo export CLASSPATH=$JAVA_HOME/lib:$JAVA_HOME/jre/lib:$CLASSPATH >> /etc/profile; echo export PATH=$JAVA_HOME/bin:$JAVA_HOME/jre/bin:$PATH >> /etc/profile; source /etc/profile; exit\" \n"," \n",
3. 安装配置Hadoop
下载安装Hadoop：
"aria2c $HadoopUrl \n","mkdir -p $HADOOP_HOME \ntar zxvf hadoop-*.tar.gz -C $HADOOP_HOME \ncd $HADOOP_HOME \nmv hadoop-*.*/* ./ \nrmdir hadoop-*.* \n","echo >> /etc/profile \n","echo export HADOOP_HOME=$HADOOP_HOME >> /etc/profile \n","echo export HADOOP_MAPRED_HOME=$HADOOP_HOME >> /etc/profile \n","echo export HADOOP_COMMON_HOME=$HADOOP_HOME >> /etc/profile \n","echo export HADOOP_COMMON_LIB_NATIVE_DIR=$HADOOP_HOME/lib/native >> /etc/profile \n","echo export YARN_HOME=$HADOOP_HOME >> /etc/profile \n","echo export HADOOP_HDFS_HOME=$HADOOP_HOME >> /etc/profile \n","echo export HADOOP_CONF_DIR=$HADOOP_HOME/etc/hadoop >> /etc/profile \n","echo export HADOOP_OPTS=-Djava.library.path=$HADOOP_HOME/lib:$HADOOP_HOME/lib/native >> /etc/profile \n","echo export PATH=$HADOOP_HOME/bin:$HADOOP_HOME/sbin:$PATH >> /etc/profile \n","echo export CLASSPATH=.:$CLASSPATH:$HADOOP__HOME/lib >> /etc/profile \n","source /etc/profile \n"," \n","mkdir -p $HADOOP_HOME/tmp \n","mkdir -p $HADOOP_HOME/dfs/name \n","mkdir -p $HADOOP_HOME/dfs/data \n",###此处要对这4个文件进行正确配置，具体内容请参考模板Hadoop_Distributed_Env_3_ecs.json.core-site.xml，hdfs-site.xml，mapred-site.xml，yarn-site.xml###"ssh root@$ipaddr_slave1 \"mkdir -p $HADOOP_HOME; exit\" \n","ssh root@$ipaddr_slave2 \"mkdir -p $HADOOP_HOME; exit\" \n","scp -r $HADOOP_HOME/* root@$ipaddr_slave1:$HADOOP_HOME \n","scp -r $HADOOP_HOME/* root@$ipaddr_slave2:$HADOOP_HOME \n"," \n","cd $HADOOP_HOME/etc/hadoop \n","echo $ipaddr_slave1 > slaves \n","echo $ipaddr_slave2 >> slaves \n",
4. 启动测试集群
最后格式化HDFS，关闭防火墙，启动集群。
"hadoop namenode -format \n","systemctl stop firewalld \n","start-dfs.sh \n","start-yarn.sh \n",
急速部署Hadoop集群
一键部署Hadoop集群>>
注意：
必须确保可以正确下载Jdk和Hadoop tar 包，我们可以选择类似如下的URL： /otn-pub/java/jdk/8u121-b13/e9e7ea248e2c4826b92b3f075a80e441/jdk-8u121-linux-x64.tar.gz(Must set 'Cookie: oraclelicense=accept-securebackup-cookie' in Header, when download.)http://mirrors./apache/hadoop/core/hadoop-2.7.1/hadoop-2.7.1.tar.gz利用该模板创建时，只能选择CentOS系统；为了防止Timeout 失败，可以设置为120分钟；我们选择的数据中心在上海。
测试部署结果
创建完成后，查看资源栈概况：
浏览器中输入图中的的WebsiteUrl，得到如下结果，则部署成功：
ROS示例模板
Hadoop_Distributed_Env_3_ecs.json：通过该模板可以一键部署上面的集群。
Hadoop_Distributed_ecsgroup.json: 该模板允许用户指定slaves节点的数量。
