想象一下这种场景：我们使用1000台廉价的PC机做Hadoop集群，虽然Hadoop号称高可用，低成本；但是廉价机器谁能保证不出现问题呢，况且世界上本身就没有不出问题的电脑，于是今天坏掉一台机器，明天需要扩充增加一个节点增加容量，但是有一个问题SSH免密码登录的认证的公钥文件在各个电脑上不能共享，如果增加一个节点，新产生的id_rsa.pub 文件在各个PC的authorized_keys文件中不存在，因此各个PC拒绝新节点来访问自己，因为新节点没有报到，此时管理员疯了：要把新节点的id_rsa.pub 文件加入到各个PC的authorized_keys中,管理员的噩梦了..................
配置SSH免密码登录，需要公钥和私钥，其中公钥向外公开，私钥自己私有，公钥里面可以盛多个主机的公钥文件，而私钥文件仅能包含自己。对ssh软件来说，私钥和公钥都要放在.ssh目录中。ssh免密码登录是将公钥放在远端需要登录的主机.ssh中，而私钥放在本地.ssh目录中，另外一个公钥文件可以存储多个公钥，而一个私钥只能存储本机一个私钥。因此我们通过nfs共享的是公钥文件authorized_keys，而私钥文件却不能共享。
所 以，我们的做法是： 各节点的.ssh目录仍然是相互独立，不共享，但各节点.ssh目录中的authorized_keys是一个软链接，指向我们事先创建好的nfs共享目 录中的文件，这样各节点往.ssh/authorized_keys追加公钥数据时，其他所有的节点就都能看到了
教你一手，修改主机名字
[root@bogon ~]# vi /etc/sysconfig/network
network networking/ network-scripts/
[root@bogon ~]# vi /etc/sysconfig/network
#gaojingsong
NETWORKING=yes
HOSTNAME=node3
1、配置NFS共享
[root@node1 ~]# ls
anaconda-ks.cfg install.log portmap-4.0-7.i386.rpm rlwrap-0.37
Desktop install.log.syslog Public rlwrap-0.37.tar.gz
Documents Music readline-6.2 Templates
Downloads Pictures readline-6.2.tar.gz Videos
[root@node1 ~]# rpm -ivh portmap-4.0-7.i386.rpm
Preparing... ########################################### [100%]
1:portmap ########################################### [100%]
[root@node1 ~]# service portmap start
Starting portmapper: /bin/bash: line 1: 2489 Segmentation fault (core dumped) portmap
[FAILED]
[root@node1 ~]# rpm -q nfs-utils portmap
nfs-utils-1.2.3-39.el6.i686
portmap-4.0-7.i386
估计是版本问题，不想仔细研究，使用yum好了
[root@node1 ~]# yum install portmap
Loaded plugins: fastestmirror, refresh-packagekit, security
Loading mirror speeds from cached hostfile
* base: mirrors.163.com
* extras: mirrors.sina.cn
* updates: centosx4.centos.org
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package portmap.i386 0:4.0-8 will be obsoleted
---> Package rpcbind.i686 0:0.2.0-11.el6 will be updated
---> Package rpcbind.i686 0:0.2.0-11.el6_7 will be obsoleting
--> Finished Dependency Resolution
Dependencies Resolved
=======================================================================
Package Arch Version Repository Size
========================================================================
Installing:
rpcbind i686 0.2.0-11.el6_7 updates 51 k
replacing portmap.i386 4.0-8
Transaction Summary
=============================================================
Install 1 Package(s)
Total download size: 51 k
Is this ok [y/N]: y
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
Warning: RPMDB altered outside of yum.
Installing : rpcbind-0.2.0-11.el6_7.i686 1/3
Erasing : portmap-4.0-8.i386 2/3
Non-fatal POSTUN scriptlet failure in rpm package portmap
Cleanup : rpcbind-0.2.0-11.el6.i686 3/3
error reading information on service portmap: No such file or directory
warning: %postun(portmap-4.0-8.i386) scriptlet failed, exit status 1
Verifying : rpcbind-0.2.0-11.el6_7.i686 1/3
Verifying : portmap-4.0-8.i386 2/3
Verifying : rpcbind-0.2.0-11.el6.i686 3/3
Installed:
rpcbind.i686 0:0.2.0-11.el6_7
Replaced:
portmap.i386 0:4.0-8
Complete!
[root@node1 ~]# yum install nfs-utils
Loaded plugins: fastestmirror, refresh-packagekit, security
Loading mirror speeds from cached hostfile
* base: mirror.neu.edu.cn
* extras: mirror.neu.edu.cn
* updates: centosv4.centos.org
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package nfs-utils.i686 1:1.2.3-39.el6 will be updated
---> Package nfs-utils.i686 1:1.2.3-64.el6 will be an update
--> Processing Dependency: python-argparse for package: 1:nfs-utils-1.2.3-64.el6.i686
--> Running transaction check
---> Package python-argparse.noarch 0:1.2.1-2.1.el6 will be installed
--> Finished Dependency Resolution
Running Transaction
Installing : python-argparse-1.2.1-2.1.el6.noarch 1/3
Updating : 1:nfs-utils-1.2.3-64.el6.i686 2/3
Cleanup : 1:nfs-utils-1.2.3-39.el6.i686 3/3
Verifying : 1:nfs-utils-1.2.3-64.el6.i686 1/3
Verifying : python-argparse-1.2.1-2.1.el6.noarch 2/3
Verifying : 1:nfs-utils-1.2.3-39.el6.i686 3/3
Dependency Installed:
python-argparse.noarch 0:1.2.1-2.1.el6
Updated:
nfs-utils.i686 1:1.2.3-64.el6
Complete!
二、修改配置文件
[root@node1 ~]# vim /etc/exports
/home/hadoop/.ssh 192.168.*(rw,wdelay,root_squash,no_subtree_check,fsid=0)
[root@node1 ~]# service rpcbind start
[root@node1 ~]# service nfs start
Starting NFS services: [ OK ]
Starting NFS quotas: [ OK ]
Starting NFS mountd: [ OK ]
Starting NFS daemon: [ OK ]
Starting RPC idmapd: [ OK ]
[root@node1 ~]# rpcinfo -p
program vers proto port service
100000 4 tcp 111 portmapper
100000 3 tcp 111 portmapper
100000 2 tcp 111 portmapper
100000 4 udp 111 portmapper
100000 3 udp 111 portmapper
100000 2 udp 111 portmapper
100024 1 udp 3510 status
100021 1 tcp 55646 nlockmgr
100021 3 tcp 55646 nlockmgr
100021 4 tcp 55646 nlockmgr
三、创建用户，并用该用户产生密钥
[root@node1 ~]# useradd hadoop
[root@node1 ~]# passwd hadoop
Changing password for user hadoop.
New password:
BAD PASSWORD: it is based on a dictionary word
BAD PASSWORD: is too simple
Retype new password:
passwd: all authentication tokens updated successfully.
[root@node1 ~]# su - hadoop
[hadoop@node1 ~]$ ssh-keygen -t rsa
[hadoop@node1 ~]$ cp .ssh/id_rsa.pub .ssh/authorized_keys
[hadoop@node1 ~]$ ssh 192.168.1.110
The authenticity of host '192.168.1.110 (192.168.1.110)' can't be established.
RSA key fingerprint is df:a1:53:ce:e0:59:0f:23:41:cd:04:16:23:e4:8b:e7.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.1.110' (RSA) to the list of known hosts.
reverse mapping checking getaddrinfo for bogon [192.168.1.110] failed - POSSIBLE BREAK-IN ATTEMPT!
[hadoop@node1 ~]$ exit
logout
Connection to 192.168.1.110 closed.
四、检查 NFS 服务器是否输出共享的目录
[root@node1 ~]# service nfs restart
Shutting down NFS daemon: [ OK ]
Shutting down NFS mountd: [ OK ]
Shutting down NFS quotas: [ OK ]
Shutting down NFS services: [ OK ]
Shutting down RPC idmapd: [ OK ]
Starting NFS services: [ OK ]
Starting NFS quotas: [ OK ]
Starting NFS mountd: [ OK ]
Starting NFS daemon: [ OK ]
Starting RPC idmapd: [ OK ]
[root@node1 ~]# exportfs
/home/hadoop/.ssh 192.168.*
如果再次修改了exports文件,不用重启NFS,重新加载一次就可以
[root@node1 ~]# exportfs -rv
查看加载结果
[root@node1 ~]# exportfs -v
[root@node1 home]# chmod -R 777 hadoop/
-------------------------------------------------------------------------------------------------------
一、客户机挂载，创建soft link
挂载之前，先保证两端软件一致
[root@node3 ~]# yum install portmap
[root@node3 ~]# yum install nfs-utils
[root@node3 ~]# chkconfig rpcbind on
[root@node3 ~]# chkconfig nfs on
[root@node3 ~]# service rpcbind start
root@node3 ~]# useradd hadoop
[root@node3 ~]# passwd hadoop
Changing password for user hadoop.
New password:
BAD PASSWORD: it is based on a dictionary word
BAD PASSWORD: is too simple
Retype new password:
passwd: all authentication tokens updated successfully.
[root@node1 ~]# su - hadoop
[root@node3 ~]# showmount -e 192.168.1.110
Export list for 192.168.1.110:
/home/hadoop/.ssh 192.168.*
[root@node3 ~]# mount 192.168.1.110:/home/hadoop/.ssh /home/exp
教你一手：如果想实现客户端自动挂载，修改 vim /etc/fstab文件
二、新建用于放置挂载文件的目录,
[root@node3 ~]# mkdir -p /home/exp
注意/home/exp权限能允许挂载:
[root@node3 /]# ll /home
drwxr-xr-x 2 root root 4096 Aug 11 01:10 exp
三、挂载NFS服务器中的目录,挂载到本地的/home/exp
[root@node3 ~]# mount 192.168.1.110:/home/hadoop/.ssh /home/exp
[root@node3 ~]# cd /home/exp/
[root@node3 exp]# ls
authorized_keys id_rsa id_rsa.pub known_hosts
[hadoop@node3 .ssh]$ cat authorized_keys
ssh-rsa AAAABjGPb2zQ== hadoop@node1
[root@node3 ~]# ll /home
total 8
drwxr-xr-x. 2 root root 4096 Mar 12 04:18 exp
drwx------. 4 hadoop hadoop 4096 Mar 12 04:22 hadoop
[root@node3 ~]# su - hadoop
将挂载目录的authorized_keys 软连接到hadoop用户的.ssh目录下
(注意:因为源文件和目标文件不再同一个目录,所以源文件和目标文件一定要使用绝对路径,
否则会出现错误Too many levels of symbolic links错误)
[root@node3 ~]$ ln -s /home/exp/authorized_keys /home/hadoop/.ssh/
[hadoop@node3 ~]$ ssh-keygen -t rsa
[hadoop@node3 .ssh]$ cat .ssh/id_rsa.pub >> .ssh/authorized_keys
--------------------------------------------------------------------------------------------------------------------
验证免密码登录
[hadoop@node3 .ssh]$ ssh 192.168.1.110
The authenticity of host '192.168.1.110 (192.168.1.110)' can't be established.
RSA key fingerprint is df:a1:53:ce:e0:59:0f:23:41:cd:04:16:23:e4:8b:e7.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.1.110' (RSA) to the list of known hosts.
reverse mapping checking getaddrinfo for bogon [192.168.1.110] failed - POSSIBLE BREAK-IN ATTEMPT!
[email protected]'s password:
Last login: Sat Mar 12 04:35:39 2016 from 192.168.1.110
[hadoop@node1 ~]$ exit
logout
Connection to 192.168.1.110 closed.
[hadoop@node3 .ssh]$ ssh 192.168.1.104
The authenticity of host '192.168.1.104 (192.168.1.104)' can't be established.
RSA key fingerprint is df:a1:53:ce:e0:59:0f:23:41:cd:04:16:23:e4:8b:e7.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.1.104' (RSA) to the list of known hosts.
reverse mapping checking getaddrinfo for bogon [192.168.1.104] failed - POSSIBLE BREAK-IN ATTEMPT!
[email protected]'s password:
[hadoop@node3 ~]$ exit
logout
Connection to 192.168.1.104 closed.
[hadoop@node3 .ssh]$
主节点实验
[hadoop@node1 ~]$ ssh 192.168.1.104
The authenticity of host '192.168.1.104 (192.168.1.104)' can't be established.
RSA key fingerprint is df:a1:53:ce:e0:59:0f:23:41:cd:04:16:23:e4:8b:e7.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.1.104' (RSA) to the list of known hosts.
reverse mapping checking getaddrinfo for bogon [192.168.1.104] failed - POSSIBLE BREAK-IN ATTEMPT!
[email protected]'s password:
Last login: Sat Mar 12 10:16:51 2016 from 192.168.1.104
[hadoop@node3 ~]$ exit
logout
Connection to 192.168.1.104 closed.
[hadoop@node1 ~]$ ssh 192.168.1.110
reverse mapping checking getaddrinfo for bogon [192.168.1.110] failed - POSSIBLE BREAK-IN ATTEMPT!
[email protected]'s password:
Last login: Sat Mar 12 10:27:44 2016 from 192.168.1.104
[hadoop@node1 ~]$ exit
增加新节点实验
[root@node2 ~]# yum install nfs-utils
Loaded plugins: fastestmirror, refresh-packagekit, security
Loading mirror speeds from cached hostfile
* base: mirrors.163.com
* extras: mirrors.163.com
* updates: mirrors.163.com
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package nfs-utils.i686 1:1.2.3-39.el6 will be updated
---> Package nfs-utils.i686 1:1.2.3-64.el6 will be an update
--> Processing Dependency: python-argparse for package: 1:nfs-utils-1.2.3-64.el6.i686
--> Running transaction check
---> Package python-argparse.noarch 0:1.2.1-2.1.el6 will be installed
--> Finished Dependency Resolution
Total download size: 380 k
Is this ok [y/N]: y
Downloading Packages:
(1/2): nfs-utils-1.2.3-64.el6.i686.rpm | 333 kB 00:00
(2/2): python-argparse-1.2.1-2.1.el6.noarch.rpm | 48 kB 00:00
----------------------------------------------------------------------------------------------------------------
Total 51 kB/s | 380 kB 00:07
warning: rpmts_HdrFromFdno: Header V3 RSA/SHA1 Signature, key ID c105b9de: NOKEY
Retrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
Importing GPG key 0xC105B9DE:
Userid : CentOS-6 Key (CentOS 6 Official Signing Key) <[email protected]>
Package: centos-release-6-5.el6.centos.11.1.i686 (@anaconda-CentOS-201311271240.i386/6.5)
From : /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
Is this ok [y/N]: y
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
Warning: RPMDB altered outside of yum.
Installing : python-argparse-1.2.1-2.1.el6.noarch 1/3
Updating : 1:nfs-utils-1.2.3-64.el6.i686 2/3
Cleanup : 1:nfs-utils-1.2.3-39.el6.i686 3/3
Verifying : 1:nfs-utils-1.2.3-64.el6.i686 1/3
Verifying : python-argparse-1.2.1-2.1.el6.noarch 2/3
Verifying : 1:nfs-utils-1.2.3-39.el6.i686 3/3
Dependency Installed:
python-argparse.noarch 0:1.2.1-2.1.el6
Updated:
nfs-utils.i686 1:1.2.3-64.el6
Complete!
[root@node2 ~]# chkconfig rpcbind on
[root@node2 ~]# chkconfig nfs on
[root@node2 ~]# service rpcbind start
[root@node2 ~]# showmount -e 192.168.1.110
Export list for 192.168.1.110:
/home/hadoop/.ssh 192.168.*
[root@node2 ~]# mkdir -p /home/ex
[root@node2 ~]# mkdir -p /home/exp
[root@node2 ~]# rm -rf /home/ex
[root@node2 ~]# mount 192.168.1.110:/home/hadoop/.ssh /home/exp
[root@node2 ~]# cd /home/exp/
[root@node2 exp]# ls
1.txt authorized_keys id_rsa id_rsa.pub known_hosts
[root@node2 exp]# cat authorized_keys
ssh-rsa AAAb2zQ== hadoop@node1
ssh-rsa AAAAB3NFTZaw== hadoop@node3
[root@node2 exp]# adduser hadoop
[root@node2 exp]# passwd hadoop
Changing password for user hadoop.
New password:
BAD PASSWORD: it is based on a dictionary word
BAD PASSWORD: is too simple
Retype new password:
passwd: all authentication tokens updated successfully.
[root@node2 exp]# su - hadoop
[hadoop@node2 ~]$ ln -s /home/exp/authorized_keys /home/hadoop/.ssh/
ln: target `/home/hadoop/.ssh/' is not a directory: No such file or directory
[hadoop@node2 ~]$ ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/hadoop/.ssh/id_rsa):
Created directory '/home/hadoop/.ssh'.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/hadoop/.ssh/id_rsa.
Your public key has been saved in /home/hadoop/.ssh/id_rsa.pub.
The key fingerprint is:
4a:02:e1:c8:45:17:bc:2e:13:aa:88:c9:3b:ab:bc:eb hadoop@node2
The key's randomart image is:
[hadoop@node2 ~]$ ln -s /home/exp/authorized_keys /home/hadoop/.ssh/
[hadoop@node2 ~]$ cat .ssh/id_rsa.pub >> .ssh/authorized_keys
[hadoop@node2 ~]$ cat .ssh/authorized_keys
ssh-rsa QAtQnb2zQ== hadoop@node1
ssh-rsa AAAAN5wglnFTZaw== hadoop@node3
ssh-rsa AAAAB3N6iH6BW6p7wFCufQ== hadoop@node2
[hadoop@node2 ~]$ ssh 192.168.1.110
The authenticity of host '192.168.1.110 (192.168.1.110)' can't be established.
RSA key fingerprint is df:a1:53:ce:e0:59:0f:23:41:cd:04:16:23:e4:8b:e7.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.1.110' (RSA) to the list of known hosts.
reverse mapping checking getaddrinfo for bogon [192.168.1.110] failed - POSSIBLE BREAK-IN ATTEMPT!
[email protected]'s password:
Last login: Sat Mar 12 10:29:01 2016 from 192.168.1.110
[hadoop@node1 ~]$ exit
logout
Connection to 192.168.1.110 closed.
[hadoop@node2 ~]$ ssh 192.168.1.103
The authenticity of host '192.168.1.103 (192.168.1.103)' can't be established.
RSA key fingerprint is df:a1:53:ce:e0:59:0f:23:41:cd:04:16:23:e4:8b:e7.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.1.103' (RSA) to the list of known hosts.
reverse mapping checking getaddrinfo for bogon [192.168.1.103] failed - POSSIBLE BREAK-IN ATTEMPT!
[email protected]'s password:
Last login: Tue Mar 15 04:48:13 2016 from 192.168.1.104
[hadoop@node2 ~]$ exit
logout
Connection to 192.168.1.103 closed.
[hadoop@node2 ~]$ ssh 192.168.1.104
The authenticity of host '192.168.1.104 (192.168.1.104)' can't be established.
RSA key fingerprint is df:a1:53:ce:e0:59:0f:23:41:cd:04:16:23:e4:8b:e7.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.1.104' (RSA) to the list of known hosts.
reverse mapping checking getaddrinfo for bogon [192.168.1.104] failed - POSSIBLE BREAK-IN ATTEMPT!
[email protected]'s password:
Last login: Sat Mar 12 10:17:38 2016 from 192.168.1.110
备注：关于NFS操作不同版本可能略有不同，可以参考