PXE+kickstart部署系統

PXE

• DHCP伺服器
• DHCP的實作
• • DHCP服務
  • DHCP伺服器
  • • 安裝DHCP伺服器
    • 配置檔案
    • 示例
• PXE安裝
• • PXE原理
  • centos7
  • centos6

PXE(preboot execute environment，預啟動執行環境)是由Intel公司開發的最新技術，工作于Client/Server的網絡模式，支援工作站通過網絡從遠端伺服器下載下傳映像，并由此支援通過網絡啟動作業系統，在啟動過程中，終端要求伺服器配置設定IP位址，再用TFTP（trivial file transfer protocol）或MTFTP(multicast trivial file transfer protocol)協定下載下傳一個啟動軟體包到本機記憶體中執行，由這個啟動軟體包完成終端（用戶端）基本軟體設定，進而引導預先安裝在伺服器中的終端作業系統。

簡單來說PXE是可以基于網絡功能來為一個沒有作業系統的用戶端來安裝系統，它所依賴的服務有dhcp，tftp，fileserver以及kickstart。

DHCP伺服器

動态主機設定協定（英語：Dynamic Host Configuration Protocol，DHCP）是一個區域網路的網絡協定，使用UDP協定工作，主要有兩個用途：用于内部網或網絡服務供應商自動配置設定IP位址；給使用者用于内部網管理者作為對所有計算機作中央管理的手段。

DHCP工作原理：

• 用戶端使用mac位址向DHCP伺服器發送廣播，請求DHCP伺服器配置設定位址
• DHCP伺服器在收到請求之後，最先拿到請求的那台DHCP伺服器會向用戶端發送一個offer封包，其中包含用戶端能夠使用的位址。當然其他DHCP伺服器上的offer也會陸續到達。
• 但是用戶端隻能處理一個offer，是以它就向最先得到請求的DHCP服務發送響應封包。這時候用戶端還沒有真正得到位址，隻是将帶有ip位址的結果回複給伺服器。是以用戶端以廣播的形式再次發送給所有DHCP伺服器，DHCP伺服器根據用戶端發來的封包進行比對，如果一樣，就給用戶端位址響應，如果不一樣，直接丢棄
• DHCP伺服器向用戶端發送一個ACK封包
• 用戶端拿到位址。如果位址可用，就會加入到租約池中。到期自動釋放位址。如果位址不可用，将給DCP伺服器發送DHCP Decline封包，通知DHCP Server禁用這個IP位址，然後DHCP Client開始新的位址申請過程。
• 在租期到50%的時候，用戶端會以單點傳播的形式向DHCP發送request封包來續租位址，如果用戶端成功收到DHCP的ACK封包，則續約成功。如果沒有續約成功就繼續使用目前這個位址。
• 在使用租期到87.5%的時候，用戶端會以廣播的形式向DHCP伺服器發送REQUEST封包，如果收到DHCP的ACK封包，則續約成功，如果沒有就繼續使用，直到ip位址到期，用戶端向DCHP伺服器發送release封包來釋放這個位址，并開始申請新的ip位址

DHCP的實作

兩種服務：

• DHCP
• dnsmaq

DHCP服務

• 伺服器：

  dhcp-server

  監聽在

  67/udp

• 用戶端：

  dhcpclient

  監聽在

  68/udp

DHCP伺服器

安裝DHCP伺服器

[[email protected] ~]# yum install -y dhcp
           

配置檔案

[[email protected] ~]# rpm -ql dhcp
/etc/dhcp/dhcpd.conf
/usr/lib/systemd/system/dhcpd.service
/usr/lib/systemd/system/dhcrelay.service
....
           

dhcpd.conf是沒有内容的，需要将示例拷貝過來使用

[[email protected] ~]# cat /etc/dhcp/dhcpd.conf 
#
# DHCP Server Configuration file.
#   see /usr/share/doc/dhcp*/dhcpd.conf.example
#   see dhcpd.conf(5) man page
#


[[email protected] ~]# cp /usr/share/doc/dhcp-4.2.5/dhcpd.conf.example /etc/dhcp/dhcpd.conf 
cp：是否覆寫"/etc/dhcp/dhcpd.conf"？ y

           

[[email protected] dhcp]# vim dhcpd.conf 

  1 # dhcpd.conf
  2 #
  3 # Sample configuration file for ISC dhcpd
  4 #
  5 
  6 # option definitions common to all supported networks...
  7 option domain-name "example.org";   # 搜尋域。比如說你隻www，你在這邊定義了一個，它會自動給你不全後面的example.org
  8 option domain-name-servers ns1.example.org, ns2.example.org;#DNS伺服器
  9 
 10 default-lease-time 600;  #預設租期
 11 max-lease-time 7200;    #最大租期
 12 
 13 # Use this to enble / disable dynamic dns updates globally.
 14 #ddns-update-style none;
 15 
 16 # If this DHCP server is the official DHCP server for the local
 17 # network, the authoritative directive should be uncommented.
 18 #authoritative;
 19 
 20 # Use this to send dhcp log messages to a different log file (you also
 21 # have to hack syslog.conf to complete the redirection).
 22 log-facility local7;
 23 
 24 # No service will be given on this subnet, but declaring it helps the 
 25 # DHCP server to understand the network topology.
 26 
 27 subnet 10.152.187.0 netmask 255.255.255.0 {#這個隻是個示例，不用填寫，隻給你一個參考
 28 }
 29 
 30 # This is a very basic subnet declaration.  這是一個基本的子網生命
 31 
 32 subnet 10.254.239.0 netmask 255.255.255.224 {
 33   range 10.254.239.10 10.254.239.20;  #起始的網址
 34   option routers rtr-239-0-1.example.org, rtr-239-0-2.example.org;  #指明一些選項
 35 }
 36 
 37 # This declaration allows BOOTP clients to get dynamic addresses,
 38 # which we don't really recommend.
 39 
 40 subnet 10.254.239.32 netmask 255.255.255.224 {
 41   range dynamic-bootp 10.254.239.40 10.254.239.60;
 42   option broadcast-address 10.254.239.31;
 43   option routers rtr-239-32-1.example.org;
 44 }
 45 
 46 # A slightly different configuration for an internal subnet.
 47 subnet 10.5.5.0 netmask 255.255.255.224 {  #一些選項的參考
 48   range 10.5.5.26 10.5.5.30;
 49   option domain-name-servers ns1.internal.example.org;
 50   option domain-name "internal.example.org";
 51   option routers 10.5.5.1;
 52   option broadcast-address 10.5.5.31;
 53   default-lease-time 600;
 54   max-lease-time 7200;
 55 }
 56 
 57 # Hosts which require special configuration options can be listed in
 58 # host statements.   If no address is specified, the address will be
 59 # allocated dynamically (if possible), but the host-specific information
 60 # will still come from the host declaration.
 61 
 62 host passacaglia {
 63   hardware ethernet 0:0:c0:5d:bd:95;
 64   filename "vmunix.passacaglia"; #指明主機的引導檔案，相當于bootloader，一會兒pxe會用到
 65   server-name "toccata.fugue.com"; #指明引導檔案的ip位址。
 66 }
 67 
 68 # Fixed IP addresses can also be specified for hosts.   These addresses
 69 # should not also be listed as being available for dynamic assignment.
 70 # Hosts for which fixed IP addresses have been specified can boot using
 71 # BOOTP or DHCP.   Hosts for which no fixed address is specified can only
 72 # be booted with DHCP, unless there is an address range on the subnet
 73 # to which a BOOTP client is connected which has the dynamic-bootp flag
 74 # set.
 75 host fantasia {   # 為特定的主機綁定位址 
 76   hardware ethernet 08:00:07:26:c0:a5;  #主機的mac位址
 77   fixed-address fantasia.fugue.com;    #配置設定的ip位址
 78 }
 79 
 80 # You can declare a class of clients and then do address allocation
 81 # based on that.   The example below shows a case where all clients
 82 # in a certain class get addresses on the 10.17.224/24 subnet, and all
 83 # other clients get addresses on the 10.0.29/24 subnet.
 84 
 85 class "foo" {
 86   match if substring (option vendor-class-identifier, 0, 4) = "SUNW";
 87 }
 88 
 89 shared-network 224-29 {
 90   subnet 10.17.224.0 netmask 255.255.255.0 {
 91     option routers rtr-224.example.org;
 92   }
 93   subnet 10.0.29.0 netmask 255.255.255.0 {
 94     option routers rtr-29.example.org;
 95   }
 96   pool {
 97     allow members of "foo";
 98     range 10.17.224.10 10.17.224.250;
 99   }
100   pool {
101     deny members of "foo";
102     range 10.0.29.10 10.0.29.230;
103   }
104 }

           

示例

1）伺服器端

2）檢視伺服器端綁定的位址

3）檢視用戶端擷取情況

4）使用dhclient檢視

PXE安裝

PXE原理

• client向PXE server上的DHCP伺服器發送ip位址請求資訊，DHCP檢測client是否合法（主要是檢測client的網卡位址），如果合法就傳回client的ip位址，同時将啟動檔案pxelinux.0的位置消息一并傳給client
• client向PXE server上的TFTP伺服器發送擷取pelinux.0的請求消息，TFTP接收到請求之後在向client發送pelinux.0的大小資訊，試探client是否滿意，當TFTP收到client傳回的同意消息之後，向client發送pxelinux.0
• client接受到pxelinux.0
• client向TFTP server發送針對本機的配置資訊檔案(在FTP伺服器的pxelinux.cfg目錄下)，TFTP将配置檔案發回client，繼而client根據配置檔案執行後繼續操作。
• client向TFTP發送linux核心請求資訊，TFTP收到消息後将核心檔案發送給client
• client向TFTP發送根檔案請求資訊，TFTP收到消息後将根檔案發送給client
• client啟動核心檔案
• client下載下傳安裝源檔案，讀取自動化安裝腳本

centos7

需要準備的前期工作：

• 服務：

  tftp-server,httpd,dhcp

• 關閉iptables，selinux

1）檢查iptables和selinux

[[email protected] ~]# iptables -vnL
Chain INPUT (policy ACCEPT 2295 packets, 6442K bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain OUTPUT (policy ACCEPT 2085 packets, 153K bytes)
 pkts bytes target     prot opt in     out     source               destination


[[email protected] ~]# getenforce
Disabled

           

2）安裝tftp-server httpd dhcp

[[email protected] ~]# yum install -y httpd tftp-server dhcp
           

3)測試tftp-server是否能連接配接

[[email protected] ~]# tftp 192.168.199.123
tftp> get fs111
tftp> exit
?Invalid command
tftp> quit
[[email protected] ~]# ls
anaconda-ks.cfg  f1  fs111  install.log  install.log.syslog

           

4)挂載CD光牒到httpd服務裡

[[email protected] ~]# mkdir /var/www/html/centos/7 -pv
mkdir: 已建立目錄 "/var/www/html/centos"
mkdir: 已建立目錄 "/var/www/html/centos/7"
[[email protected] ~]# mount /dev/sr0 /var/www/html/centos/7
mount: /dev/sr0 寫保護，将以隻讀方式挂載

           

5）建立ks檔案，放到httpd服務下

[[email protected] ~]# ls /var/www/html
centos  ks7.cfg

#測試下是否可通路

           

6)準備DHCP伺服器

[[email protected] ~]# cp /usr/share/doc/dhcp-4.2.5/dhcpd.conf.example /etc/dhcp/dhcpd.conf 

[[email protected] dhcp]# cat dhcpd.conf
This is a very basic subnet declaration.
subnet 192.168.30.0 netmask 255.255.255.0 {
  	range 192.168.30.10 192.168.30.20;
  	option routers 192.168.30.1;
  	filename "pxelinux.0";
   next-server 192.168.30.2;#位址一定要寫成同網段的，要不然沒法連
	option domain-name-servers 1.1.1.1,114.114.114.114;
	option domain-name "ydong.com";
	default-lease-time 600;
	max-lease-time 7200; 
}
#隻修改了此處
           

1. 安裝syslinux包為擷取pxelinux.0檔案

[[email protected] tftpboot]# yum install -y syslinux

           

8）将pxeliinux.0(相當于bootloader) 和menu.c32(菜單背景） 到tftp的預設/var/lib/tftpboot目錄下

[[email protected] tftpboot]# cp /usr/share/syslinux/{menu.c32,pxelinux.0} ./
[[email protected] tftpboot]# ls
menu.c32  pxelinux.0

           

9)複制CD光牒裡的核心

vmlinuz

和initrd檔案

initrd.image

到tftpboot目錄下

[[email protected] tftpboot]# cp /var/www/html/centos7/isolinux/{vmlinuz,initrd.img} /var/lib/tftpboot/
[[email protected] tftpboot]# ls
initrd.img  menu.c32  pxelinux.0  vmlinuz

           

10)複制CD光牒裡的isolinux.cfg（菜單選項）到tftpboot目錄下的

pxelinux.cfg檔案夾

裡。并且改名為default

[[email protected] tftpboot]# mkdir pxelinux.cfg
[[email protected] tftpboot]# ls
initrd.img  menu.c32  pxelinux.0  pxelinux.cfg  vmlinuz

[[email protected] tftpboot]# cp /var/www/html/centos7/isolinux/isolinux.cfg /var/lib/tftpboot/pxelinux.cfg/default
[[email protected] tftpboot]# ls pxelinux.cfg
default

           

11)準備centos7的啟動菜單

[[email protected] isolinux]# cp vesamenu.c32 splash.png /var/lib/tftpboot/
[[email protected] tftpboot]# cat pxelinux.cfg/default 
default vesamenu.c32   #由于menu.c32太醜了，我又重新複制了vesamenu.c32背景做菜單選項。
timeout 600

display boot.msg

# Clear the screen when exiting the menu, instead of leaving the menu displayed.
# For vesamenu, this means the graphical background is still displayed without
# the menu itself for as long as the screen remains in graphics mode.
menu clear
menu background splash.png
menu title CentOS 7
menu vshift 8
menu rows 18
menu margin 8
#menu hidden
menu helpmsgrow 15
menu tabmsgrow 13

# Border Area
menu color border * #00000000 #00000000 none

# Selected item
menu color sel 0 #ffffffff #00000000 none

# Title bar
menu color title 0 #ff7ba3d0 #00000000 none

# Press [Tab] message
menu color tabmsg 0 #ff3a6496 #00000000 none

# Unselected menu item
menu color unsel 0 #84b8ffff #00000000 none

# Selected hotkey
menu color hotsel 0 #84b8ffff #00000000 none

# Unselected hotkey
menu color hotkey 0 #ffffffff #00000000 none

# Help text
menu color help 0 #ffffffff #00000000 none

# A scrollbar of some type? Not sure.
menu color scrollbar 0 #ffffffff #ff355594 none

# Timeout msg
menu color timeout 0 #ffffffff #00000000 none
menu color timeout_msg 0 #ffffffff #00000000 none

# Command prompt text
menu color cmdmark 0 #84b8ffff #00000000 none
menu color cmdline 0 #ffffffff #00000000 none

# Do not display the actual menu unless the user presses a key. All that is displayed is a timeout message.

menu tabmsg Press Tab for full configuration options on menu items.

menu separator # insert an empty line
menu separator # insert an empty line

label linux
  menu label ^Install CentOS 7
  kernel vmlinuz
  append initrd=initrd.img ks=http://192.168.30.2/ks7.cfg quiet   #這邊應該寫跟dhcp同網段的位址。



label local
  menu label Boot from ^local drive
  localboot 0xffff

menu separator # insert an empty line
menu separator # insert an empty line

label returntomain
  menu label Return to ^main menu
  menu exit

menu end


           

12）測試

安裝期間出了錯誤，都是将位址寫成了接外網的網卡位址，如果使用pxe安裝的話，一定都要基于本地的方式連接配接。

centos6

centos6和centos7差不多，隻是指令上的差別而已。為了不讓centos7上的DHCP影響，關閉7的dhcp服務。

添加網卡之後centos6報錯：

使用

ip a

指令檢視eth1的mac位址，然後添加到對應的配置檔案中即可

1）安裝服務

[[email protected] ~]# yum install -y httpd tftp-server dhcp
           

2)測試tftp-server能否使用

3）将CD光牒檔案挂載至httpd服務目錄下

[[email protected] html]# cat /etc/fstab 
/dev/sr0		/var/www/html/centos6	iso9660	defaults 	0 0

[[email protected] html]# mount -a
mount: block device /dev/sr0 is write-protected, mounting read-only

           

4）制作兩個ks檔案

[[email protected] html]# ls /var/www/html
centos6  ks6_desktop.cfg  ks6_mini.cfg

           

5)配置dhcp伺服器

[[email protected] ~]# service dhcpd start
正在啟動 dhcpd：                                           [确定]

32 subnet 192.168.30.0 netmask 255.255.255.0 {
 33         range 192.168.30.10 192.168.30.20;
 34         option routers 192.168.30.1;
 35         filename "pxelinux.0";
 36         next-server 192.168.30.2;
 37         option domain-name-servers 114.114.114.114;
 38         option domain-name "ydong.com";
 39         default-lease-time 600;
 40         max-lease-time 7200;
 41 }

           

6）複制所需的檔案到tftpboot目錄下

1)
[[email protected] ~]# mkdir /var/lib/tftpboot/pxelinux.cfg
[[email protected] tftpboot]# ls /var/lib/tftpboot/
pxelinux.cfg

2)
[[email protected] tftpboot]# cp /usr/share/syslinux/{pxelinux.0,vesamenu.c32} /var/lib/tftpboot/
[[email protected] tftpboot]# ls
pxelinux.0  pxelinux.cfg  vesamenu.c32

3）
[[email protected] tftpboot]# cp /var/www/html/centos6/isolinux/{boot.msg,initrd.img,vmlinuz} /var/lib/tftpboot/
[[email protected] tftpboot]# ls
boot.msg  initrd.img  pxelinux.0  pxelinux.cfg  vesamenu.c32  vmlinuz
[[email protected] tftpboot]# cp /var/www/html/centos6/isolinux/splash.jpg /var/lib/tftpboot/
#因為在isolinux.cfg檔案中調用了這個圖檔，是以還得複制圖檔

4）
[[email protected] tftpboot]# cp /var/www/html/centos6/isolinux/isolinux.cfg /var/lib/tftpboot/pxelinux.cfg/default
[[email protected] tftpboot]# cat /var/lib/tftpboot/pxelinux.cfg/default
default vesamenu.c32
#prompt 1
timeout 600

display boot.msg

menu background splash.jpg
menu title Welcome to CentOS 6.9!
menu color border 0 #ffffffff #00000000
menu color sel 7 #ffffffff #ff000000
menu color title 0 #ffffffff #00000000
menu color tabmsg 0 #ffffffff #00000000
menu color unsel 0 #ffffffff #00000000
menu color hotsel 0 #ff000000 #ffffffff
menu color hotkey 7 #ffffffff #ff000000
menu color scrollbar 0 #ffffffff #00000000

label  PXE_mini linux
  menu label Instal ^mini system
  menu default
  kernel vmlinuz
  append initrd=initrd.img ks=http://192.168.30.2/ks6_mini.cfg
label PXE_desktop linux
  menu label install ^desktop system
  kernel vmlinuz
  append initrd=initrd.img ks=http://192.168.39.2/ks6_desktop.cfg
label local
  menu label Boot from ^local drive
  localboot 0xffff
           

7）測試