介紹

本篇文章主要介紹sudo配置和用法，為了給某個用戶控制許可權比如執行某個命令或者關機操作等，伺服器管理員通常會給這個用戶配置sudo，接下來就來詳細介紹具體的配置方法。

環境：centos6.7

結構說明

可以通過編輯文件/etc/sudoers來配置，通常使用visudo命令來進行修改，因為如果你修改的格式不符合它會進行提示。接下來就通過一個格式來瞭解它

<user> <host> = [<operator user> [<par>]] <command list>

chenmh localhost = (root)    NOPASSWD: /bin/mkdir test

<user>:指的是具體的用戶或者用戶別名，如果使用%user指的是用戶組。

<host>:指的是具體的host(可以是機器名也可以是ip)或者是host別名，ALL代表所有的host。

<operator user>:可選，指定可以用調用哪個用戶的來執行，ALL代表調用root用戶來執行。這裡要說明一下root用戶的許可權代表什麼意思，比如一個目錄的所有者是root，那麼必須具備root用戶的許可權才能執行相關操作,比如上面的chenmh用戶如果它配置的是其它用戶比如它自己，那麼它在root所有者的目錄下麵是沒許可權執行操作的。同樣如果這裡配置的是哪個用戶那麼比如mkdir創建的文件夾就的所有者就是哪個用戶。預設不指定代表使用ALL

<par>:可選，指定參數，通常使用NOPASSWD（代表該用戶在執行sudo的時候不需要再輸入自己的密碼）。

<command list>：指定的具體命令或者是命令別名或者是ALL,ALL代表所有許可權。

說明： [<operator user> [<par>]]這兩個選項是可以選的可以不指定，如果不指定預設是調用root用戶執行，但是使用sudo必須輸入用戶自己的密碼

配置文件

接下來詳細來看看它的配置文件，它的配置文件以及很詳細的告訴了我們該怎樣使用，在前面一部分是示例怎樣將一組許可權創建組別名，註意別名需要大寫，

## Sudoers allows particular users to run various commands as
## the root user, without needing the root password.
##
## Examples are provided at the bottom of the file for collections
## of related commands, which can then be delegated out to particular
## users or groups.
## 
## This file must be edited with the 'visudo' command.

##可以將多個host配置成一個host別名
## Host Aliases 
## Groups of machines. You may prefer to use hostnames (perhaps using 
## wildcards for entire domains) or IP addresses instead.
Host_Alias     FILESERVERS = 192.168.137.40,192.168.137.30
# Host_Alias     MAILSERVERS = smtp, smtp2

##將多個user配置成一個user別名
## User Aliases
## These aren't often necessary, as you can use regular groups
## (ie, from files, LDAP, NIS, etc) in this file - just use %groupname 
## rather than USERALIAS
User_Alias ADMINS = chenmh

###接下來是命令別名，就是將一組命令放在一起，這樣可以簡便配置
## Command Aliases
## These are groups of related commands...

## Networking
# Cmnd_Alias NETWORKING = /sbin/route, /sbin/ifconfig, /bin/ping, /sbin/dhclient, /usr/bin/net, /sbin/iptables, /usr/bin/rfcomm, /usr/bin/wvdial, /sbin/iwconfig, /sbin/mii-tool

## Installation and management of software
# Cmnd_Alias SOFTWARE = /bin/rpm, /usr/bin/up2date, /usr/bin/yum

## Services
# Cmnd_Alias SERVICES = /sbin/service, /sbin/chkconfig

## Updating the locate database
# Cmnd_Alias LOCATE = /usr/bin/updatedb

## Storage
# Cmnd_Alias STORAGE = /sbin/fdisk, /sbin/sfdisk, /sbin/parted, /sbin/partprobe, /bin/mount, /bin/umount

## Delegating permissions
# Cmnd_Alias DELEGATING = /usr/sbin/visudo, /bin/chown, /bin/chmod, /bin/chgrp 

## Processes
# Cmnd_Alias PROCESSES = /bin/nice, /bin/kill, /usr/bin/kill, /usr/bin/killall

## Drivers
# Cmnd_Alias DRIVERS = /sbin/modprobe

###這個是我自己配置的命令別名，將mkdir和rm命令配置在一起分配給某個用戶
##userdefin
Cmnd_Alias OTHERS = /bin/mkdir, /bin/rm

# Defaults specification

#
# Disable "ssh hostname sudo <cmd>", because it will show the password in clear. 
#         You have to run "ssh -t hostname sudo <cmd>".
#
Defaults    requiretty

#
# Refuse to run if unable to disable echo on the tty. This setting should also be
# changed in order to be able to use sudo without a tty. See requiretty above.
#
Defaults   !visiblepw

#
# Preserving HOME has security implications since many programs
# use it when searching for configuration files. Note that HOME
# is already set when the the env_reset option is enabled, so
# this option is only effective for configurations where either
# env_reset is disabled or HOME is present in the env_keep list.
#
Defaults    always_set_home

Defaults    env_reset
Defaults    env_keep =  "COLORS DISPLAY HOSTNAME HISTSIZE INPUTRC KDEDIR LS_COLORS"
Defaults    env_keep += "MAIL PS1 PS2 QTDIR USERNAME LANG LC_ADDRESS LC_CTYPE"
Defaults    env_keep += "LC_COLLATE LC_IDENTIFICATION LC_MEASUREMENT LC_MESSAGES"
Defaults    env_keep += "LC_MONETARY LC_NAME LC_NUMERIC LC_PAPER LC_TELEPHONE"
Defaults    env_keep += "LC_TIME LC_ALL LANGUAGE LINGUAS _XKB_CHARSET XAUTHORITY"

#
# Adding HOME to env_keep may enable a user to run unrestricted
# commands via sudo.
#
# Defaults   env_keep += "HOME"

Defaults    secure_path = /sbin:/bin:/usr/sbin:/usr/bin

## Next comes the main part: which users can run what software on 
## which machines (the sudoers file can be shared between multiple
## systems).
## Syntax:
##
##      user    MACHINE=COMMANDS
##
## The COMMANDS section may have other options added to it.
##
## Allow root to run any commands anywhere 
root    ALL=(ALL)       ALL

## Allows members of the 'sys' group to run networking, software, 
## service management apps and more.
# %sys ALL = NETWORKING, SOFTWARE, SERVICES, STORAGE, DELEGATING, PROCESSES, LOCATE, DRIVERS
###sys這個組中的用戶可以執行相關的命令組的許可權，多個命令組用逗號分隔
## Allows people in group wheel to run all commands
# %wheel        ALL=(ALL)       ALL

## Same thing without a password
# %wheel        ALL=(ALL)       NOPASSWD: ALL

## Allows members of the users group to mount and unmount the 
## cdrom as root
# %users  ALL=/sbin/mount /mnt/cdrom, /sbin/umount /mnt/cdrom
###users組的用戶可以執行掛載和卸載/mnt/cdrom目錄的許可權
## Allows members of the users group to shutdown this system
# %users  localhost=/sbin/shutdown -h now
###users組的用戶可以執行關機命令
## Read drop-in files from /etc/sudoers.d (the # here does not mean a comment)
#includedir /etc/sudoers.d

案例

1.用戶別名組中的用戶可以在FILESERVERS這組host裡面調用root用戶執行OTHERS命令組的許可權，多個命令組用逗號分隔

ADMINS  FILESERVERS=(ALL)    NOPASSWD:OTHERS

2.用戶chenmh這個用戶可以在本機以調用root用戶來執行所有的命令

chenmh localhost=(root) NOPASSWORD:ALL

3.用戶chenmh可以調用root用戶創建目錄test，也只能創建test目錄

chenmh ALL=(ALL)    NOPASSWD: /bin/mkdir test

4.dev組的用戶可以執行關機shutdown命令

%dev ALL=(ALL)    NOPASSWD:/sbin/shutdown

快捷操作 

 1.查看當前用戶具備的sudo許可權

sudo -l

User chenmh may run the following commands on this host:
    (root) NOPASSWD: /bin/mkdir, /bin/rm

總結

配置sudo記得使用visudo命令，如果配置錯誤了保存的時候它會有提示。