Unattended automated installation

PXE unattended automated installation

lab environment

dhcp server：Cerntos7 192.168.10.121

tftp server：Centos7 192.168.10.121

vsftp server: Centso7 192.168.10.122
Note: firewall, selinux are closed, yum source is a local disc image

PXE

PXE: preboot execute environment (Pre-boot Environment), developed by Intel network boot technology, working on C / S architecture, network-based boot the client operating system installation. It allows the client to download the boot image from the remote server via a network, and load the entire file or install the entire operating system.
Dependence dhcp, tftp, file server (vsftpd, httpd, nfs, etc.), the client host adapters, also need support BOOTROOM chip, supports PXE related agreements.
dhcp assigned IP address and the boot file location specified.
tftp provide guidance downloaded image file
vsftpd download the operating system installation package, copy the contents of the disc in to the file server
Network boot Linux related software provided by syslinux, syslinux need to install the program, list of related documents syslinux program: / usr / share / syslinux

TFTP Service

Trivial File Transfer Protocol (Trivial File Transfer Protocol) network file based on a simple UDP transport protocol, port UDP 69
Belonging to the C / S architecture: client tftp, server program tftp-server, based daemon xinetd to run.
xinetd configuration file: /etc/xinetd.d/tftp
tftp server provides the client file to access the root directory: / var / lib / tftpboot

PXE installation workflow automation

After the client boots broadcasts FIND frame of dhcp
dhcp server receives the IP address assignment frame is enough, and returns the address of the TFTP server
Client gets pxe boot files via tftp service, and will load the kernel image file to initialize memory to run
Get auto-answer file by default start menu location specified in the file ks.cfg initiates a request to a server tftp
tftp server automatically returns to its answer file ks.cfg
Obtaining position by the automatic response system image file, according to automate the installation and configuration files

other

pxelinux.0: pxe boot program (provided by the program syslinux)
When the system starts the boot menu, point out to load the kernel image and inird mirror, and then guide: pxelinux.cfg / default.
vmlinuz: Linux kernel
initrd.img: Initialization image files, stored for some drivers during boot

Set up practice

Set up a TFTP service

First, install the daemon xinetd (tftp services offer)
Installation tftp service

Modify the configuration file tftp

service tftp
{
        socket_type             = dgram
        protocol                = udp
        wait                    = no #不等待
        user                    = root
        server                  = /usr/sbin/in.tftpd
        server_args             = -s /var/lib/tftpboot #默认共享文件目录
        disable                 = no #是否不可以，no表示启用tftp
        per_source              = 11
        cps                     = 100 2
        flags                   = IPv4
}

Start Service

The required configuration files are placed tftp server shared directory

Where the kernel, image initialization, the boot menu
Install syslinux, and copy it came with pxe boot files to the shared directory

Cfg modify the boot menu file

default linux #默认使用linux选项
prompt 0 #是否提示  0不提示（不等待用户选择直接使用默认项） 1提示
timeout 15 #延时

label linux
  menu label ^Install CentOS 7
  kernel vmlinuz
  append initrd=initrd.img inst.ks=ftp://192.168.10.122/ks.cfg quiet  #附加参数，initrd指定初始化镜像文件位置，inst.ks指定kickstart自动应答文件位置

Note: default Specifies the default startup items, it should be set to the installation key

Use the directory tree view structure

Configuring DHCP Service Installation

install service

Modify the configuration file

subnet 192.168.10.0 netmask 255.255.255.0 {
  range 192.168.10.10 192.168.10.60;
  option domain-name-servers 114.114.114.114;
  option domain-name "www.lg.com";
  option routers 192.168.10.2;
  default-lease-time 600;
  max-lease-time 7200;
  next-server 192.168.10.121  #TFTP服务器ip地址
  filename "pxelinux.0";  #pxe引导文件名
}

Start Service
Client Test

Installation configuration VSFTP Service
- install service
- Installation kickstart (for graphical production of auto-answer file, requires a graphical interface)
- Start system-config-kickstart answer file to automatically generate graphical
  
  Set the default language, keyboard layout, time zone, root password, cpu architecture type, whether to restart after installation, whether text installation
  
  Specifies the installation for the new installation, specify the location of the system image file
  
  Specify the type of installation guide and other options
  
  Set partition configuration
  
  Add / boot partition
  
  Adding swap swap partition, swap do not need to choose a mount point
  
  Add / root partition
  
  After completion of the partition view the partition configuration
  
  Network configuration, specify when the need for additional network card configuration
  
  Password encryption to verify the configuration
  
  Firewall, SELinux configuration
  
  Display Configuration
  
  Select the packages to install, the name of the configuration file if the yum repository is not development will be the following errors
  
  Solution:
  
  Kickstart need to restart the program after modification
  
  Pre-installation configuration script execution
  
  After the installation is complete script execution configuration
  
  After the setup is complete, save the configuration file to the specified directory
  
  Placing vsftp shared directory files / var / ftp / under can
  
  Note: Use ksvalidator order to detect whether the auto-answer file syntax error
- Mount the file system image to a shared directory under the ftp