Ubuntu配置NFS

NFS 是Network File System的缩写，即网络文件系统，一种使用于分散式文件系统的协定

NFS通过网络让不同的机器、不同的操作系统能够彼此分享个别的数据，例如将/home设置为共享目录，然后共享给网络中的其它服务器，这样每台机器就不必单独建立自己的/home路径了，NFS独立于操作系统，容许不同硬件及操作系统的系统共同进行文件的分享，是在类Unix系统间实现磁盘文件共享的一种方法

NFS本身没有提供信息传输的协议和功能，而是使用RPC服务完成这部分功能。可以说NFS本身就是使用RPC服务的一个程序，或者说NFS也是一个RPC SERVER。所以只要用到NFS的地方都要启动RPC服务，不论是NFS server还是NFS client，可以这么理解RPC和NFS之间的关系：NFS是一个文件系统，而RPC负责信息的传输

一，系统环境

Linux Distribution：Ubuntu 14

二，安装Linux NFS

sean@sean:~$ sudo apt-get install nfs-kernel-server
[sudo] password for sean: 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following extra packages will be installed:
  keyutils libgssglue1 libnfsidmap2 libtirpc1 nfs-common rpcbind
Suggested packages:
  open-iscsi watchdog
The following NEW packages will be installed:
  keyutils libgssglue1 libnfsidmap2 libtirpc1 nfs-common nfs-kernel-server
  rpcbind
0 upgraded, 7 newly installed, 0 to remove and 159 not upgraded.
Need to get 460 kB of archives.
After this operation, 2,049 kB of additional disk space will be used.
Do you want to continue? [Y/n] Y
Get:1 http://cn.archive.ubuntu.com/ubuntu/ trusty/main libgssglue1 amd64 0.4-2ubuntu1 [19.7 kB]
Get:2 http://cn.archive.ubuntu.com/ubuntu/ trusty/main libnfsidmap2 amd64 0.25-5 [32.2 kB]
Get:3 http://cn.archive.ubuntu.com/ubuntu/ trusty/main libtirpc1 amd64 0.2.2-5ubuntu2 [71.3 kB]
Get:4 http://cn.archive.ubuntu.com/ubuntu/ trusty/main keyutils amd64 1.5.6-1 [33.6 kB]
Get:5 http://cn.archive.ubuntu.com/ubuntu/ trusty-updates/main rpcbind amd64 0.2.1-2ubuntu2.2 [37.1 kB]
Get:6 http://cn.archive.ubuntu.com/ubuntu/ trusty-updates/main nfs-common amd64 1:1.2.8-6ubuntu1.2 [181 kB]
Get:7 http://cn.archive.ubuntu.com/ubuntu/ trusty-updates/main nfs-kernel-server amd64 1:1.2.8-6ubuntu1.2 [85.8 kB]
Fetched 460 kB in 16s (27.2 kB/s)                                              
Selecting previously unselected package libgssglue1:amd64.
(Reading database ... 168701 files and directories currently installed.)
Preparing to unpack .../libgssglue1_0.4-2ubuntu1_amd64.deb ...
Unpacking libgssglue1:amd64 (0.4-2ubuntu1) ...
Selecting previously unselected package libnfsidmap2:amd64.
Preparing to unpack .../libnfsidmap2_0.25-5_amd64.deb ...
Unpacking libnfsidmap2:amd64 (0.25-5) ...
Selecting previously unselected package libtirpc1:amd64.
Preparing to unpack .../libtirpc1_0.2.2-5ubuntu2_amd64.deb ...
Unpacking libtirpc1:amd64 (0.2.2-5ubuntu2) ...
Selecting previously unselected package keyutils.
Preparing to unpack .../keyutils_1.5.6-1_amd64.deb ...
Unpacking keyutils (1.5.6-1) ...
Selecting previously unselected package rpcbind.
Preparing to unpack .../rpcbind_0.2.1-2ubuntu2.2_amd64.deb ...
Unpacking rpcbind (0.2.1-2ubuntu2.2) ...
Selecting previously unselected package nfs-common.
Preparing to unpack .../nfs-common_1%3a1.2.8-6ubuntu1.2_amd64.deb ...
Unpacking nfs-common (1:1.2.8-6ubuntu1.2) ...
Selecting previously unselected package nfs-kernel-server.
Preparing to unpack .../nfs-kernel-server_1%3a1.2.8-6ubuntu1.2_amd64.deb ...
Unpacking nfs-kernel-server (1:1.2.8-6ubuntu1.2) ...
Processing triggers for man-db (2.6.7.1-1ubuntu1) ...
Processing triggers for ureadahead (0.100.0-16) ...
ureadahead will be reprofiled on next reboot
Setting up libgssglue1:amd64 (0.4-2ubuntu1) ...
Setting up libnfsidmap2:amd64 (0.25-5) ...
Setting up libtirpc1:amd64 (0.2.2-5ubuntu2) ...
Setting up keyutils (1.5.6-1) ...
Setting up rpcbind (0.2.1-2ubuntu2.2) ...
 Removing any system startup links for /etc/init.d/rpcbind ...
rpcbind start/running, process 12074
Processing triggers for ureadahead (0.100.0-16) ...
Setting up nfs-common (1:1.2.8-6ubuntu1.2) ...

Creating config file /etc/idmapd.conf with new version

Creating config file /etc/default/nfs-common with new version
Adding system user `statd' (UID 118) ...
Adding new user `statd' (UID 118) with group `nogroup' ...
Not creating home directory `/var/lib/nfs'.
statd start/running, process 12307
gssd stop/pre-start, process 12341
idmapd start/running, process 12399
Processing triggers for ureadahead (0.100.0-16) ...
Setting up nfs-kernel-server (1:1.2.8-6ubuntu1.2) ...

Creating config file /etc/exports with new version

Creating config file /etc/default/nfs-kernel-server with new version
 * Not starting NFS kernel daemon: no exports.
Processing triggers for libc-bin (2.19-0ubuntu6.7) ...
Processing triggers for ureadahead (0.100.0-16) ...

通过安装日志可以发现总共会安装keyutils，libgssglue1，libnfsidmap2，libtirpc1，nfs-common，nfs-kernel-server，rpcbind这7个包

很多文档中安装的包为portmap，但是这个包已经被rpcbind替代

sean@sean:~$ sudo apt-get install portmap
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Note, selecting 'rpcbind' instead of 'portmap'
rpcbind is already the newest version.
0 upgraded, 0 newly installed, 0 to remove and 164 not upgraded.

rpcbind包安装完成后会自动启动rpcbind服务

sean@sean:~$ ps -ef|grep rpcbind
root        807      1  0 22:27 ?        00:00:00 rpcbind
sean      10215   9528  0 22:48 pts/6    00:00:00 grep --color=auto rpcbind

但是由于目前NFS的配置文件为空，NFS服务并没有启动

三，配置NFS服务

从安装日志中我们可以发现NFS服务的配置文件为/etc/exports，并且这个文件在安装过程中已经生成好了，我们所要做的就是将NFS配置信息添加到这个文件中

sean@sean:~$ sudo vi /etc/exports

# /etc/exports: the access control list for filesystems which may be exported
#               to NFS clients.  See exports(5).
#
# Example for NFSv2 and NFSv3:
# /srv/homes       hostname1(rw,sync,no_subtree_check) hostname2(ro,sync,no_subtree_check)
#
# Example for NFSv4:
# /srv/nfs4        gss/krb5i(rw,sync,fsid=0,crossmnt,no_subtree_check)
# /srv/nfs4/homes  gss/krb5i(rw,sync,no_subtree_check)
/home/sean/shareDir 192.168.137.129(rw,no_root_squash,async)

其中中的最后一行为新添加的NFS配置，NFS配置信息格式如下：

<共享目录> [客户端1 选项（访问权限,用户映射,其他）] [客户端2 选项（访问权限,用户映射,其他）]

1，共享目录：

共享目录是指NFS系统中需要共享给客户机使用的目录

2，客户端：

客户端是指网络中可以访问NFS共享目录的计算机

客户端常用的指定方式：

(1)指定ip地址的主机：192.168.0.1
(2)指定子网中的所有主机：192.168.0.0/255.255.255.0
(3)指定域名的主机：www.sean.com
(4)指定域中的所有主机：*.sean.com
(5)所有主机：*

3，选项：

选项用来设置输出目录的访问权限、用户映射等，NFS主要有3类选项：

访问权限选项：

(1)设置输出目录只读：ro
(2)设置输出目录读写：rw

用户映射选项：

(1)all_squash：将远程访问的所有普通用户及所属组都映射为匿名用户或用户组（nfsnobody）
(2)no_all_squash：与all_squash取反（默认设置）
(3)root_squash：将root用户及所属组都映射为匿名用户或用户组（默认设置）
(4)no_root_squash：与rootsquash取反
(5)anonuid=xxx：将远程访问的所有用户都映射为匿名用户，并指定该用户为本地用户（UID=xxx）
(6)anongid=xxx：将远程访问的所有用户组都映射为匿名用户组账户，并指定该匿名用户组账户为本地用户组账户（GID=xxx）

其它选项：

(1)secure：限制客户端只能从小于1024的tcp/ip端口连接nfs服务器（默认设置）
(2)insecure：允许客户端从大于1024的tcp/ip端口连接服务器
(3)sync：将数据同步写入内存缓冲区与磁盘中，效率低，但可以保证数据的一致性
(4)async：将数据先保存在内存缓冲区中，必要时才写入磁盘
(5)wdelay：检查是否有相关的写操作，如果有则将这些写操作一起执行，这样可以提高效率（默认设置）
(6)no_wdelay：若有写操作则立即执行，应与sync配合使用
(7)subtree：若输出目录是一个子目录，则nfs服务器将检查其父目录的权限(默认设置)
(8)no_subtree：即使输出目录是一个子目录，nfs服务器也不检查其父目录的权限，这样可以提高效率

四，启动NFS服务

sean@sean:~$ sudo service nfs-kernel-server start
 * Exporting directories for NFS kernel daemon...                                                                                                                                exportfs: /etc/exports [1]: Neither 'subtree_check' or 'no_subtree_check' specified for export "192.168.137.129:/home/sean/shareDir".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

                                                                                                                                                                          [ OK ]
 * Starting NFS kernel daemon   
sean@sean:~$ sudo service nfs-kernel-server status
nfsd running
sean@sean:~$ ps -ef|grep nfsd
root      10536      2  0 23:40 ?        00:00:00 [nfsd4]
root      10537      2  0 23:40 ?        00:00:00 [nfsd4_callbacks]
root      10539      2  0 23:40 ?        00:00:00 [nfsd]
root      10540      2  0 23:40 ?        00:00:00 [nfsd]
root      10541      2  0 23:40 ?        00:00:00 [nfsd]
root      10542      2  0 23:40 ?        00:00:00 [nfsd]
root      10543      2  0 23:40 ?        00:00:00 [nfsd]
root      10544      2  0 23:40 ?        00:00:00 [nfsd]
root      10545      2  0 23:40 ?        00:00:00 [nfsd]
root      10546      2  0 23:40 ?        00:00:00 [nfsd]
sean      10566   9528  0 23:41 pts/6    00:00:00 grep --color=auto nfsd

通过命令可以看到文件夹已经被共享

sean@sean:~$ showmount -e
Export list for sean:
/home/sean/shareDir 192.168.137.129

五，客户端挂载NFS共享目录

sean@ubuntu:~$ sudo mount 192.168.137.128:/home/sean/shareDir /home/sean/shared
mount: wrong fs type, bad option, bad superblock on 192.168.137.128:/home/sean/shareDir,
       missing codepage or helper program, or other error
       (for several filesystems (e.g. nfs, cifs) you might
       need a /sbin/mount. helper program)
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

上网查看了一下错误原因，是因为客户端没有安装nfs-common包

sean@ubuntu:~$ sudo apt-get install nfs-common

之后再次使用挂载命令即可，此时如果我们再次查看客户端挂载的磁盘，就可以看到NFS共享目录已经被挂载上了

sean@ubuntu:~$ df
Filesystem                          1K-blocks    Used Available Use% Mounted on
udev                                   488800       4    488796   1% /dev
tmpfs                                   99904    1456     98448   2% /run
/dev/sda1                            19478204 3745568  14720156  21% /
none                                        4       0         4   0% /sys/fs/cgroup
none                                     5120       0      5120   0% /run/lock
none                                   499512     152    499360   1% /run/shm
none                                   102400      40    102360   1% /run/user
/dev/sr0                              1044480 1044480         0 100% /media/sean/Ubuntu 14.04.4 LTS amd64
192.168.137.128:/home/sean/shareDir  19478272 4288896  14176896  24% /home/sean/shared

此时如果我们在128的/home/sean/shareDir目录下创建一个文件，在129的/home/sean/shared目录下可以看到一个名称相同的文件，并且文件的内容也相同

六，开机启动NFS服务

安装完成之后查看系统服务

sean@sean:~$ runlevel
N 2
sean@sean:~$ ll /etc/rc2.d
total 20
drwxr-xr-x   2 root root  4096  6月 20 23:25 ./
drwxr-xr-x 132 root root 12288  6月 26 20:16 ../
-rw-r--r--   1 root root   677  2月 17 12:59 README
lrwxrwxrwx   1 root root    20  2月 22 06:33 S20kerneloops -> ../init.d/kerneloops*
lrwxrwxrwx   1 root root    27  6月 20 23:25 S20nfs-kernel-server -> ../init.d/nfs-kernel-server*
lrwxrwxrwx   1 root root    15  2月 22 06:33 S20rsync -> ../init.d/rsync*
lrwxrwxrwx   1 root root    27  2月 22 06:33 S20speech-dispatcher -> ../init.d/speech-dispatcher*
lrwxrwxrwx   1 root root    15  2月 22 06:33 S50saned -> ../init.d/saned*
lrwxrwxrwx   1 root root    19  2月 22 06:33 S70dns-clean -> ../init.d/dns-clean*
lrwxrwxrwx   1 root root    18  2月 22 06:33 S70pppd-dns -> ../init.d/pppd-dns*
lrwxrwxrwx   1 root root    21  2月 22 06:33 S99grub-common -> ../init.d/grub-common*
lrwxrwxrwx   1 root root    18  2月 22 06:33 S99ondemand -> ../init.d/ondemand*
lrwxrwxrwx   1 root root    18  2月 22 06:33 S99rc.local -> ../init.d/rc.local*

nfs-kernel-server是自动启动，就不需要再进行修改了，而rpcbind就比较麻烦了，找了半天才找到vi /etc/init/rpcbind-boot.conf

# portmap-boot

description "Upstart job to start rpcbind on boot only"
author "Clint Byrum"

emits start-rpcbind

start on virtual-filesystems and net-device-up IFACE=lo

task

exec initctl emit --no-wait start-rpcbind ON_BOOT=y

可以见到这个服务设为开机启动了

七，开机自动挂载共享盘

这时候我们需要修改的文件是/etc/fstab，命令格式如下：

:<共享目录> <本地目录> <文件系统类型> <选项>  

每个字段的具体含义这里就不详细解释了，vi /etc/fstab，在文件中添加下面这行配置

192.168.137.128:/home/sean/shareDir /home/sean/shared nfs defaults 0 0

系统每次启动时即会自动挂载共享盘