====== 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. 

  * 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 [[linux_wiki:os_install_bare_metal#netinstall_iso_prep|NFS as an Installation Server]]

----

====== TFTP Server ======

  * Install the required packages<code bash>yum install tftp-server xinetd</code>
  * Allow TFTP access (set disable = no)<code bash>vim /etc/xinetd.d/tftp
service tftp
{
  ....some other variables...
  disable = no
  ....some other variables...
}</code>
  * Start and Enable xinetd<code bash>systemctl start xinetd
systemctl enable xinetd</code>
  * Allow through firewall (if enabled)<code bash>firewall-cmd --permanent --add-service=tftp
firewall-cmd --reload</code>

----

====== DHCP Server ======

  * Install required package<code bash>yum install dhcp</code>
  * Edit DHCP config and customize per your network<code bash>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" ;
}
</code>
    * 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<code bash>systemctl start dhcp
systemctl enable dhcp</code>

----

====== 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<code bash>yum install syslinux</code>

  * Create the PXE Linux directory structure<code bash>mkdir -p /var/lib/tftpboot/pxelinux.cfg
mkdir /var/lib/tftpboot/centos7/</code>

  * Copy the pxelinux.0 data file<code bash>cp /usr/share/syslinux/pxelinux.0 /var/lib/tftpboot/</code>

  * Create the PXE Linux default config file (replace '<nfs-ip>' with actual NFS server IP<code bash>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/
</code>
    * 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<code bash>cp /boot/grub/splash.xpm.gz /var/lib/tftpboot/</code>

  * Copy the files (images/pxeboot/vmlinuz and initrd.img) from the install disk to /var/lib/tftpboot/centos7/<code bash>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/</code>

  * Restart dhcpd and xinetd<code bash>systemctl restart dhcpd
systemctl restart xinetd</code>

\\
**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)

----