General Information

In order to install an OS via PXE boot, a TFTP and DHCP server are required.
Using PXE allows for clients to begin a network installation without any net-install ISO.

• Reference Source: http://www.tecmint.com/install-pxe-network-boot-server-in-centos-7/

Checklist

• Distro(s): Enterprise Linux 7
• Other: Installation Server Created (NFS/HTTP/FTP) that is hosting the install DVD and kickstart file
  • Example: Using NFS as an Installation Server

• Install the required packages

  yum install tftp-server xinetd

• Allow TFTP access (set disable = no)

  vim /etc/xinetd.d/tftp
  service tftp
  {
    ....some other variables...
    disable = no
    ....some other variables...
  }

• Start and Enable xinetd

  systemctl start xinetd
  systemctl enable xinetd

• Allow through firewall (if enabled)

  firewall-cmd --permanent --add-service=tftp
  firewall-cmd --reload

• Install required package

  yum install dhcp

• Edit DHCP config and customize per your network

  vim /etc/dhcp/dhcpd.conf
   
  subnet 192.168.1.0 netmask 255.255.255.0 {
    option routers 192.168.1.254 ;
    range 192.168.1.240 192.168.1.250 ;
    next-server 192.168.1.150 ;
    filename "pxelinux.0" ;
  }

  • subnet ⇒ specify the network
  • netmask ⇒ mask for your network
  • option routers ⇒ gateway for the network
  • range ⇒ start and ending IP to hand out via DHCP
  • next-server ⇒ IP of the TFTP server
  • filename ⇒ file that should be offered to systems doing PXE boot (relative to the TFTP server's root)
• Start and enable DHCP

  systemctl start dhcp
  systemctl enable dhcp

Now that both required services are setup, it is time to create the PXE boot content to be handed out over TFTP.

• Install a required package

  yum install syslinux

• Create the PXE Linux directory structure

  mkdir -p /var/lib/tftpboot/pxelinux.cfg
  mkdir /var/lib/tftpboot/centos7/

• Copy the pxelinux.0 data file

  cp /usr/share/syslinux/pxelinux.0 /var/lib/tftpboot/

• Create the PXE Linux default config file (replace '<nfs-ip>' with actual NFS server IP

  vim /var/lib/tftpboot/pxelinux.cfg/default
   
  default menu.c32
  prompt 0
  timeout 600
   
  menu title ########## PXE Boot Menu ##########
  label 1
    menu label ^1) Install CentOS 7.2 x86-64
    kernel centos7/vmlinuz
    append initrd=centos7/initrd.img method=nfs:<nfs-ip>:/iso/centos7.2-dvd/

  • PXE Boot Menu Reference Source: https://wiki.centos.org/HowTos/PXE/PXE_Setup/Menus

• To include a splash image when doing PXE, copy the image from the local system

  cp /boot/grub/splash.xpm.gz /var/lib/tftpboot/

• Copy the files (images/pxeboot/vmlinuz and initrd.img) from the install disk to /var/lib/tftpboot/centos7/

  mount -t iso9660 -o loop CentOS-7-x86_64-DVD-1511.iso /mnt
  cp /mnt/images/pxeboot/vmlinuz /var/lib/tftpboot/centos7/
  cp /mnt/images/pxeboot/initrd.img /var/lib/tftpboot/centos7/

• Restart dhcpd and xinetd

  systemctl restart dhcpd
  systemctl restart xinetd

The system is now ready to accept incoming PXE boot requests.

/var/lib/tftpboot/ contains:

• centos7 (directory)
• pxelinux.0 (data file)
• pxelinux.cfg (directory)
• splash.xpm.gz (splash image)

/var/lib/tftpboot/centos7 contains:

• initrd.img (centos 7 initrd)
• vmlinuz (centos 7 boot kernel)

/var/lib/tftpboot/pxelinux.cfg contains:

• default (config file)