[[linux_wiki:os_install_pxe_boot]]

OS Install: PXE Boot

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.

Checklist

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

TFTP 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

DHCP Server

  • 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

Create PXE Content

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/
  • 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)

  • linux_wiki/os_install_pxe_boot.txt
  • Last modified: 2019/05/26 03:50
  • (external edit)