Before configuring the first domain name with a good map Ha details refer to my other essays
After the download is good hdfs.tar.gz
In the / home / ldy
mkdir apps/
tar -xzvf hdfs.tar.gz -C / home / ldy / apps / # hdfs and designed to install the jdk
Modify environment variables: vim / etc / profile
Add in the last fi above
export HDP_HOME = / home / ldy / apps / hadoop-2.8.5 / etc / hadoop # paths vary from person
export PATH=$PATH:$HDP_HOME/sbin : $HDP_HOME/bin
hadoop-daemon.sh sbin directory commands in the (old in bin) is preferably equipped with both. jdk configuration is the same reason
Profiles:
In /home/ldy/apps/hadoop-2.8.5/etc/hadoop
vim hadoop-env.sh # tell it to java_home
Vim core-site.xml
Vim hdfs-site.xml
Note: core-site.xml configuration error can cause incorrect namenode addr
Value of the name tag can not be modified
After the domain name mapping can write the host name, and the core-site.xml the addresses of all servers must be consistent, be sure to use the same file system
Configure the look secondary namenodes :( this is optimized settings, will be equipped with better)
I suggest that you first with a good one server and then copy and paste files to another server, save trouble
Here remote connection requires open ssh and scp
Open ssh:
Run ps -e | grep ssh, sshd process to see if there
If not, explain server did not start, start the server process through /etc/init.d/ssh -start, if prompted ssh does not exist then it is not installed server
Install server
1.sudo apt-get update
2.sudo apt-get install openssh-server
apt-get过程中可能出现:
E: Could not get lock /var/lib/dpkg/lock-frontend - open (11: Resource temporarly unavailable)
E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), is an other process using it?
当出现这个报错时直接：
sudo rm /var/lib/dpkg/lock-frontend
sudo rm /var/lib/dpkg/lock
接下来有可能还会报下面的错：
E: Could not get lock /var/lib/apt/lists/lock - open (11: Resource temporarily unavailable)
Unable to lock directory /var/lib/apt/lists
sudo rm /var/lib/apt/lists/lock
apt-get update 即可
Scp :
scp -r /home/ldy/apps/hadoop-2.8.5 ubuntu-01:/home/ldy/apps/
报错： ssh连接The authenticity of host can't be established
修改/etc/ssh/ssh_config文件的配置
修改：（没有就在最后面添加）
StrictHostKeyChecking no
注：一般是禁止root用户登录的，切换到普通用户可正常使用
当出现这个错误时：
Permisson denied ,please try again
当出现这个错误时，被拒绝，是因为ssh的权限问题，需要修改权限，进入到/etc/ssh文件夹下，用root用户修改文件sshd_config
将PermitRootLogin no 改为 PermitRootLogin yes
记得重启ssh：sudo service ssh restart
hadoop namenode -format (一次就够了）
start-dfs.sh (开启namenode和datanode服务)
使用这个命令每次都要输密码，这里可以设一个免密登录，在namenode服务器上设比较好
免密登录：
ssh-keygen;(一直回车就行)
ssh-copy-id 主机名;(有多少个主机执行多少次这个命令)
vim etc/hadoop/slaves (加上所有需要免密的主机名)
注意：虚拟机重启后得重新执行 start-dfs.sh，namenode和datanode才启动（其本质是软件）
若有不对敬请指正........