How to Configure PXE Server on CentOS 7.x with DHCP Proxy.

PXE stands for Preboot eXecution Environment, which will help to install a system in the network without using physical media. Unlike traditional installation methods, we can install any system in the network without having a CD/DVD or USB drives. It is used to enable a network computer to boot only from a network interface card. This method will be very helpful if a System Administrator wants to install many systems that don’t have a CD/DVD device on the network.

With the help of the PXE server, we can install hundreds of systems at the same time.

My test box (PXE server) details

Operating System: CentOS 7 Minimal.

IP Address: 192.168.10./24.

SELinux: Disabled.

Firewalld: Enable.

In this tutorial, we will learn how to install the PXE server on CentOS 7 with The existing DHCP and install CentOS 7 on the client machine.

Step 1: Install required packages for PXE Setup

To install and configure the PXE server, need the following packages. “Dnsmasq, TFTP-server,  syslinux,  vsftpd”. Open the terminal with administrative privilege and execute the below command.

[root@pxe ~]# yum -y install dnsmasq tftp-server syslinux vsftpd

Step 2: Configure Dnsmasq Server

Dnsmasq default configuration file is located in /etc directory.

Note: Take a backup before editing any configuration file.

Run the following command to take the Dnsmasq configuration file backup.

[root@pxe ~]# cp /etc/dnsmasq.conf  /etc/dnsmasq.conf.bkp

After backup, open the configuration file with your favorite editor.

[root@pxe ~]# vi /etc/dnsmasq.conf 

Delete all the content of the file, copy and paste the below content.

# Port Options
port=0
interface=ens160,lo  # Replace the port name as your server.
  
# DHCP Options
dhcp-range=192.168.1.1,proxy,255.255.255.0 # Replace your dhcp server IP and subnet mask here.
dhcp-option=vendor:PXEClient,6,2b
dhcp-no-override
  
# PXE
dhcp-boot=pxelinux.0
pxe-service=X86PC, "CentOS 7 PXE boot ", pxelinux
  
# TFTP Options
enable-tftp
tftp-root=/var/lib/tftpboot 

Once edited, save the file.

Step 3: SYSLINUX Bootloaders

SYSLINUX is a boot loader for the Linux operating system which runs on an MS-DOS/Windows FAT filesystem. It is intended to simplify the first-time installation of Linux, and for creation of rescue and other special-purpose boot disks.

Copy all bootloaders files provided by the Syslinux package from /usr/share/syslinux to /var/lib/tftpboot path by executing the following commands.

[root@pxe ~]#   cp -r /usr/share/syslinux/* /var/lib/tftpboot

Step 3: Mount the CentOS ISO

In this step, we will mount the CentOS 7 ISO and copy the kernel files into tftp-boot directory.

[root@pxe ~]#   mkdir -P /opt/iso

Download or copy the CentOS 7 ISO to /opt/iso path. After the download create a directory in /var/ftp/ path, to mount the ISO by executing below command.

[root@pxe ~]#   mkdir -P /var/ftp/CentOS-7

Mount the ISO to /var/ftp/CentOS-7 path, by executing the below command.

[root@pxe ~]#  mount -o loop /opt/iso/CentOS-7-x86_64-DVD-1810.iso  /var/ftp/CentOS-7

If you want to mount the disk permanently, you have to make the below entry in /etc/fstab.

[root@pxe ~]#  vi /etc/fstab

Result:

Add the below line in the fstab file and save it.

/opt/iso/ CentOS-7-x86_64-DVD-1810.iso   /var/ftp/CentOS-8 iso9660 defaults,loop 0 0

Once you edited the /etc/fstab file, execute the below command to make sure is everything is proper and mount the drive.

[root@pxe ~]#  mount -a

Note: This will work as you local centos mirror through FTP.

Note: If there is an issue in /etc/fstab, you should solve it before restarting the server, otherwise the OS will not boot properly.

Step 4: PXE Server Configuration File

Create the pxelinux.cfg directory and populate it with the default file by using the following command.

[root@pxe ~]#  mkdir /var/lib/tftpboot/pxelinux.cfg

[root@pxe ~]#  touch /var/lib/tftpboot/pxelinux.cfg/default

Open the PXE server configuration file with your favorite editor and edit it as follows. Remember that all paths used in this file must be relative to the /var/lib/tftpboot directory.

[root@pxe ~]#  vi /var/lib/tftpboot/pxelinux.cfg/default

Add the following lines as per your configuration.

default vesamenu.c32

prompt 0

MENU TITLE PXE Server Boot Menu

# Local Hard Disk pxelinux.cfg default entry

LABEL 1

    MENU LABEL ^1) Boot local hard drive

    menu default

    localboot 0

    timeout 600

    TOTALTIMEOUT 60000

# CentOS 7 pxelinux.cfg default entry

LABEL 2

    MENU LABEL ^2) Install CentOS-7

    KERNEL /CentOS7/vmlinuz

    APPEND initrd=/CentOS7/initrd.img inst.ks=ftp://192.168.1.10/ks.cfg

Save the file. how to create anaconda file ks.cfg for automated installation .

Step 5: Copy CentOS 7 Boot Images to TFTP boot

For this setup, we need CentOS kernel and initrd file for the initial boot. Copy the kernel and initrd file from the mounted disk by using the following command.

[root@pxe ~]#  mkdir /var/lib/tftpboot/CentOS7

[root@pxe ~]#  cp /var/ftp/CentOS-7/images/pxeboot/vmlinuz /var/lib/tftpboot/CentOS7

[root@pxe ~]#  cp /var/ftp/CentOS-7/images/pxeboot/initrd.img /var/lib/tftpboot/CentOS7

Step 6: Start and Enable the services

Client machines to reach the PXE server and boot the OS from the server. Open the DNSMASQ,  VSFTPD and TFTP boot ports in the firewall by using the following commands.

firewall-cmd –add-service=ftp –permanent

firewall-cmd –add-service=dns –permanent

firewall-cmd –add-service=dhcp –permanent

firewall-cmd –add-port=69/udp –permanent

firewall-cmd –add-port=4011/udp –permanent

firewall-cmd –reload

Step 8: Boot the client from the network

Configure the client machine to boot for the network by editing system BIOS or F12 key. Now you should able to see the PXE menu, select Install CentOS-7, and press enter.

That’s all for “how-to configure the PXE server with dhcp proxy“. Please refer to How to create anaconda/ks .cfg/kickstart file for unattended installation.  

Leave a Reply

Your email address will not be published. Required fields are marked *