Automatic installation using PXE CentOS7.6

First, demand

• New base 300 servers, we need to implement self-install CentOS7.6 version of the operating system, choose to use PXE batch installation.

Second, prepare for work

• Layer 2 switches connected to the server operating system is not installed, to avoid affecting the normal existing network server.
• Upload the operating system image to the server and install the PXE environment essential services.
• Mount image file as a local depot.
  • Preparing the Environment

  mkdir -p /var/www/html/CentOS1810/
  mount /tmp/CentOS-7-x86_64-DVD-1810.iso /var/www/html/CentOS1810
  mkdir /etc/yum.repos.d/backup 
  mv /etc/yum.repos.d/{*,backup}   # 报错不需要理会
  cat >/etc/yum.repos.d/local.repo<<EOF
  [local_repo]
  name=local_repo
  baseurl=file:///var/www/html/CentOS1810
  gpgcheck=0
  EOF
  yum clean all && yum makecache 
  yum install httpd dhcp xinetd tftp-server syslinux -y

  Third, the service configuration

• The dhcp service
  • Modify dhcp server configuration file

  mv /etc/dhcp/dhcpd.conf{,.bak}   # 备份默认配置文件
  cat>/etc/dhcp/dhcpd.conf<<EOF
  subnet 10.0.0.0 netmask 255.255.255.0 {     # 定义分配的网段和掩码
  range 10.0.0.1 10.0.0.252;                  # 定义分配的地址范围
  next-server 10.0.0.253;                     # 指定引导文件的服务器IP地址
  filename "pxelinux.0";                      # 指定引导文件名称 
  }
  EOF
  systemctl start dhcp
  systemctl enable dhcp
  ss -nltup |grep :67

• Tftp-server configuration
  • Edit /etc/xinetd.d/tftp file

  sed -i '/disable/s/yes/no/' /etc/xinetd.d/tftp
  systemctl start xinetd
  systemctl enable xinetd
  ss -nltup |grep :69

• Copy the boot files to the default home directory tftp service

  cp -a /var/www/html/CentOS1810/isolinux/* /var/lib/tftpboot/
  cp -a /usr/share/syslinux/pxelinux.0 /var/lib/tftpboot/
  mkdir /var/lib/tftpboot/pxelinux.cfg 
  cp -a /var/www/html/CentOS1810/isolinux/isolinux.cfg  /var/lib/tftpboot/pxelinux.cfg/default