说明：

• 目前安装了4个Redhat linux操作系统，主机名分别为hadoop01,hadoop02,hadoop03,hadoop04
• 其中hadoop01为主节点，hadoop02，hadoop03,hadoop04为从节点
• 四个节点ip地址为192.168.10.61~64.
• 如果不修改hosts文件，从第二部开始可将hadoop01~04改为所对应的ip地址，如第4步中的scp ~/.ssh/id_rsa.pub root@hadoop02:~命令可改为scp ~/.ssh/id_rsa.pub root@192.168.10.62:~

第1步：hosts文件修改（可选）

如果将来想采用ssh 主机名的方式来访问其余节点，请确保各个节点上的hosts文件下有对各个ip以及主机名的映射，可通过如下命令进行查看

<code class="language-shell hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">cat /etc/hosts</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

 
如果没有将ip地址与主机名相对应，请按照如上所示，修改hosts文件

<code class="language-shell hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">vim /etc/hosts</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

第2步：生成密钥对

在每个节点上执行如下命令来生成密钥对，一直点击回车即可

<code class="language-shell hljs lasso has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">ssh<span class="hljs-attribute" style="box-sizing: border-box;">-keygen</span> <span class="hljs-attribute" style="box-sizing: border-box;">-t</span> rsa <span class="hljs-attribute" style="box-sizing: border-box;">-P</span> <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">''</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

第3步：本机ssh访问

在每个节点上执行如下命令将公钥文件写入授权文件中，并赋值权限

<code class="language-shell hljs avrasm has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">cat ~/<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.ssh</span>/id_rsa<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.pub</span> >> ~/<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.ssh</span>/authorized_keys
chmod <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">600</span> ~/<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.ssh</span>/authorized_keys</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>

在每个节点上可通过输入两次ssh 本节点主机名命令来验证（注意，第一次输入ssh 本节点主机名会询问，输入yes，以后就不需要输入密码了） 

第4步：主节点到从节点无密码ssh访问

在主节点分别执行如下命令将主节点的公钥文件拷贝到从节点上（注意，当进行远程拷贝的时候会要求输入节点的密码）

<code class="language-shell hljs ruby has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">scp ~<span class="hljs-regexp" style="color: rgb(0, 136, 0); box-sizing: border-box;">/.ssh/id</span>_rsa.pub  root<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">@hadoop02</span><span class="hljs-symbol" style="color: rgb(0, 102, 102); box-sizing: border-box;">:~</span>
scp ~<span class="hljs-regexp" style="color: rgb(0, 136, 0); box-sizing: border-box;">/.ssh/id</span>_rsa.pub  root<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">@hadoop03</span><span class="hljs-symbol" style="color: rgb(0, 102, 102); box-sizing: border-box;">:~</span>
scp ~<span class="hljs-regexp" style="color: rgb(0, 136, 0); box-sizing: border-box;">/.ssh/id</span>_rsa.pub  root<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">@hadoop04</span><span class="hljs-symbol" style="color: rgb(0, 102, 102); box-sizing: border-box;">:~</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul>

 
在从节点中执行如下命令，将主节点的公钥追加到授权文件中

<code class="language-shell hljs avrasm has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">cat  ~/id_rsa<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.pub</span> >>  ~/<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.ssh</span>/authorized_keys
chmod <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">600</span> ~/<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.ssh</span>/authorized_keys
rm ~/id_rsa<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.pub</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul>

 
在主节点中执行如下命令，实现主节点到从节点无密码访问

<code class="language-shell hljs bash has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">ssh hadoop02
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">exit</span>
ssh hadoop03
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">exit</span>
ssh hadoop04
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">exit</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li></ul>

第5步：从节点到主节点无密码ssh访问

在每个从节点上执行如下命令，实现从节点到主节点的无密码访问

<code class="language-shell hljs dos has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">cd</span>  
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">cd</span>  .ssh
ssh-<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">copy</span>-id -i id_rsa.pub root@hadoop01</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul>

在每个从节点上执行如下命令，验证从节点到主节点无密码ssh访问。

<code class="language-shell hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">ssh hadoop01</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>