Network Boot install Centos OS

Introduction

A network boot installation allows you to install CentOS to a system with access to an installation server. At a minimum, two approaches are required for a network installation:

PXE Server: A system running a DHCP server, a TFTP server, and an HTTP, HTTPS, FTP, or NFS server. While each server can run on a different physical system, the procedures in this section assume a single system is running all servers.

Client: The system to which you are installing CentOS. Once installation starts, the client queries the DHCP server, receives the boot files from the TFTP server, and downloads the installation image from the HTTP, HTTPS, FTP, or NFS server. Unlike other installation methods, the client does not require any physical boot media for the installation to start.

To boot a client from the network, configure it in BIOS/UEFI or a quick boot menu. On some hardware, the option to boot from a network might be disabled, or not available.

Items that are required.

1. Export the installation ISO image (or the installation tree) to an NFS, HTTPS, HTTP, or FTP server.
2. Configure the TFTP server and DHCP server, and start the TFTP service on the PXE server.
3. Boot the client, and start the installation.

TFTP server for BIOS-based clients network boot

This procedure describes how to configure a TFTP server and DHCP server and start the TFTP service on the PXE server for BIOS-based AMD and Intel 64-bit systems.

As root, install the tftp-server package

# yum install tftp-server httpd

or

# dnf install tftp-server httpd

Configure your DHCP server to use the boot images packaged with SYSLINUX. A sample configuration in the /etc/dhcp/dhcpd.conf file might look like:

option space pxelinux;
option pxelinux.magic code 208 = string;
option pxelinux.configfile code 209 = text;
option pxelinux.pathprefix code 210 = text;
option pxelinux.reboottime code 211 = unsigned integer 32;
option architecture-type code 93 = unsigned integer 16;

subnet 10.0.0.0 netmask 255.255.255.0 {
	option routers 192.168.0.254;
	range 192.168.0.2 10.0.0.253;

	class "pxeclients" {
	  match if substring (option vendor-class-identifier, 0, 9) = "PXEClient";
	  next-server 192.168.0.1;

	  if option architecture-type = 00:07 {
	    filename "uefi/shim.efi";
	    } else {
	    filename "pxelinux/pxelinux.0";
	  }
	}
}

Start and enable the dhcpd service:

# systemctl start dhcpd
# systemctl enable dhcpd

Configure tftp server for network boot

# vim /etc/xinetd.d/tftp

service tftp
 {
 socket_type             = dgram
 protocol                = udp
 wait                    = yes
 user                    = root
 server                  = /usr/sbin/in.tftpd
 server_args             = -s /tftpboot
 disable                 = no
 per_source              = 11
 cps                     = 100 2
 flags                   = IPv4
 }

Start and enable the xinetd service that manages the tftp service:

# systemctl start xinetd
# systemctl enable xinetd

Setup TFTP Server network boot files

# mkdir -p /var/pxe/centos8
# mkdir /var/lib/tftpboot/centos8
# wget http://mirror.hostlink.com.hk/centos/8-stream/isos/x86_64/CentOS-Stream-8-x86_64-latest-dvd1.iso
# mount CentOS-Stream-8-x86_64-latest-dvd1.iso /var/pxe/centos8
# cp /var/pxe/centos8/images/pxeboot/{vmlinuz,initrd.img} /var/lib/tftpboot/centos8/
# cp /usr/share/syslinux/{menu.c32,vesamenu.c32,ldlinux.c32,libcom32.c32,libutil.c32} /var/lib/tftpboot/
# mkdir /var/lib/tftpboot/pxelinux.cfg

# vi /var/lib/tftpboot/pxelinux.cfg/default
# create new
# replace PXE servers hostname or IP address to your own one
default vesamenu.c32
prompt 1
timeout 60

display boot.msg

label linux
  menu label ^Install CentOS 8
  menu default
  kernel centos8/vmlinuz
  append initrd=centos8/initrd.img ip=dhcp inst.repo=http://192.168.0.30/centos8
label vesa
  menu label Install CentOS 8 with ^basic video driver
  kernel centos8/vmlinuz
  append initrd=centos8/initrd.img ip=dhcp inst.xdriver=vesa nomodeset inst.repo=http://192.168.0.30/centos8
label rescue
  menu label ^Rescue installed system
  kernel centos8/vmlinuz
  append initrd=centos8/initrd.img rescue
label local
  menu label Boot from ^local drive
  localboot 0xffff

Configure PXE configuration network boot

Dracut as the kernel command line option provider. It supports PXE booting over HTTP. Going to use the Apache 2 webserver to serve files over the network

# vi /etc/httpd/conf.d/pxeboot.conf
# create new
Alias /centos8 /var/pxe/centos8
<Directory /var/pxe/centos8>
    Options Indexes FollowSymLinks
    # access permission
    Require ip 127.0.0.1 192.168.0.0/24
</Directory>

# systemctl restart httpd