Ubuntu和CentOS如何配置SSH使得无密码登陆

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岱艾
5 years ago
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1 Ubuntu 和 CentOS 如何配置 SSH 使得无密码登陆在使用 Hadoop 的时候, 一般配置 SSH 使得我们可以无密码登录到主机, 下面分别以 Ubuntu 和 CentOS 两个平台来举例说明如何配置 SSH 使得我们可以无密码登录到主机, 当然, 你得先安装好 SSH 服务器, 并开启 ( 关于如何在 Linux 平台下安装好 SSH 请参加本博客的 Linux 平台下安装 SSH )Ubuntu 配置步骤如下所示 : [wyp@localhost ~]$ ssh-keygen -t dsa -P '' Generating public/private dsa key pair. Enter file in which to save the key (/home/wyp/.ssh/id_dsa): Created directory '/home/wyp/.ssh'. Your identification has been saved in /home/wyp/.ssh/id_dsa. Your public key has been saved in /home/wyp/.ssh/id_dsa.pub. The key fingerprint is: bd:2c:ed:ab:6d:a9:b2:45:88:32:08:5a:d2:d9:ad:cc wyp@ubuntu The key's randomart image is: +--[ DSA 1024] o. o +.. o+ o o.. o o E. S. o. o. o o.oo 这样就会在 wyp 用户的 /home/wyp/.ssh/ 目录下生成 id_dsa 和 id_dsa.pub 两个文件, 输出如下 : [wyp@ubuntu ~]$ cd /home/wyp/.ssh/ [wyp@ubuntu:~/.ssh]$ ls -l total 8 -rw wyp wyp :51 id_dsa -rw-r--r-- 1 wyp wyp :51 id_dsa.pub 1 / 5

2 将 id_dsa.pub 里面的内容加到用于认证的公钥文件中, 命令如下 ( 注意 : 不要复制, 一定要用 cat 去操作, 不信你可以去试试 ): [wyp@ubuntu:~/.ssh]$ cat id_dsa.pub >> authorized_keys 可以将这个生成的 authorized_keys 拷贝到别的机器上面 [wyp@ubuntu:~/.ssh]$ cat ~/.ssh/authorized_keys \ ssh wyp@ "cat - >> ~/.ssh/authorized_keys" 输入下面命令, 如果显示如下类似的信息, 就说明配置好了! [wyp@ubuntu:~/.ssh]$ ssh localhost The authenticity of host 'localhost (::1)' can't be established. RSA key fingerprint is 22:9b:94:45:dc:f0:c8:02:03:b2:a1:30:d3:04:92:01. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added 'localhost' (RSA) to the list of known hosts. linux ubuntu generic #83-Ubuntu SMP Wed Jan 4 11:12:07 UTC 2012 x86_64 GNU/linux Ubuntu LTS Welcome to Ubuntu! * Documentation: packages can be updated. 213 updates are security updates. New release 'precise' available. Run 'do-release-upgrade' to upgrade to it. The programs included with the Ubuntu system are free software; the exact distribution terms for each program are described in the individual files in /usr/share/doc/*/copyright. Ubuntu comes with ABSOLUTELY NO WARRANTY, to the extent permitted by applicable law. [wyp@localhost ~]$ 但是实际上, 很多人都没有这么顺利的, 一般的问题都是文件权限设置的不对, 请把.ssh 和 a uthorized_keys 的访问权限分别设置为 755 个 600( 也就是只有自己对上面两个文件有写权限 ), 命令如下 : 2 / 5

3 ~]$ chmod 755 /home/wyp/.ssh ~]$ chmod 600 /home/wyp/.ssh/authorized_keys 假如这台服务器上面还有 test 用户, 如何使得 wyp 用户能够无密码登录到 test(ip 地址为 ) 呢? 执行下面命令 ~]$ cat /home/wyp/.ssh/id_dsa.pub ssh 'cat - >> ~/.ssh/authorized_keys' 之后, 在 wyp 用户下执行下面命令 [wyp@localhost ~]$ ssh test@ linux ubuntu generic #83-Ubuntu SMP Wed Jan 4 11:12:07 UTC 2012 x86_64 GNU/linux Ubuntu LTS Welcome to Ubuntu! * Documentation: packages can be updated. 213 updates are security updates. New release 'precise' available. Run 'do-release-upgrade' to upgrade to it. Last login: Mon Oct 21 02:48: from localhost [test@localhost ~]$ 如果出现上述类似的信息, 说明成功了! 登陆到 test 用户了注意上面的信息只有第一次登录的时候才会显示, 以后登陆只会显示下面类似的信息 : [wyp@localhost ~]$ ssh test@ Last login: Mon Oct 21 02:49: from localhost [test@localhost ~]$ 3 / 5

4 上面是以 Ubuntu 平台为例子, 下面来说说怎么在 CentOS 平台上面配置,(CentOS 由于权限比 Ub untu 的更加严格, 所以配置起来比较麻烦 ), 首先, 我们需要设置一下 /etc/ssh/sshd_config 文件, 请将 /etc/ssh/sshd_config 文件中下面三行的注释去掉 : [root@localhost ~]# vim /etc/ssh/sshd_config RSAAuthentication yes PubkeyAuthentication yes AuthorizedKeysFile.ssh/authorized_keys 其余的步骤和开始的一样如下所示 : [wyp@localhost ~]$ ssh-keygen -t dsa -P '' Generating public/private dsa key pair. Created directory '/home/wyp/.ssh'. Your identification has been saved in /home/wyp/.ssh/dsa. Your public key has been saved in /home/wyp/.ssh/dsa.pub. The key fingerprint is: 15:57:37:f1:ee:05:26:3a:9e:e1:aa:b3:11:27:b3:1a wyp@localhost.localdomain The key's randomart image is: +--[ DSA 1024] oo o.o.. o... o o + S + o * o +.. E o +. o.... o [wyp@localhost ~]$ cat ~/.ssh/dsa.pub >> ~/.ssh/authorized_keys The authenticity of host 'localhost ( )' can't be established. RSA key fingerprint is f3:f8:0b:26:a1:8e:14:55:34:ec:cb:99:f8:70:2c:d3. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added 'localhost' (RSA) to the list of known hosts. Last login: Fri Aug 9 08:39: from [wyp@localhost ~]$ 好了, 配置完成了 4 / 5

5 Powered by TCPDF ( Ubuntu 和 CentOS 如何配置 SSH 使得无密码登陆如果登陆失败了, 可以通过 ssh 提供的一个参数查看错误的原因 ~]$ ssh -v localhost 如果 /etc/ssh/sshd_config 文件内容修改了,.ssh 和 authorized_keys 的权限都做了相应的修改, 但是还出现了下面的错误 Agent admitted failure to sign using the key. password: 可以用下面的方法解决 ~]$ ssh-add ~/.ssh/id_dsa Identity added: /home/wyp/.ssh/id_dsa (/home/wyp/.ssh/id_dsa) Last login: Fri Oct 25 10:50: from localhost.localdomain id_dsa 文件是上面 ssh-keygen -t dsa -P '' 生成的本博客文章除特别声明, 全部都是原创! 转载本文请加上 : 转载自过往记忆 ( 本文链接 : () 5 / 5

在Fedora上部署Hadoop2.2.0伪分布式平台

在Fedora上部署Hadoop2.2.0伪分布式平台如果你想配置完全分布式平台请参见本博客 Hadoop2.2.0 完全分布式集群平台安装与设置首先, 你得在电脑上面安装好 jdk7, 如何安装, 这里就不说了, 网上一大堆教程! 然后安装好 ssh, 如何安装请参见本博客 Linux 平台下安装 SSH 并设置好无密码登录 ( Ubuntu 和 CentOS 如何配置 SSH 使得无密码登陆 ) 好了, 上面的前提条件部署好之后, 下面将进入 Hadoop2.2.0