In this post, I have documented the steps I followed to install RHEL 8 by booting from a PXE server over the network with a Kickstart file using Synology NAS as TFTP, HTTP server, and UDM as DHCP.

  1. Install & Configure TFTP
  2. Install & Configure HTTP server
  3. Enable network boot on UDM
  4. PXE Boot setup

Install and Configure TFTP

Trivial File Transfer Protocol (TFTP) is a simple file transfer protocol, generally used for transferring configurations or boot files when authentication is not required.

Synology NAS comes with TFTP file services.

To configure TFTP

Go to Control Panel > File Services > Advanced

  1. Select Enable TFTP Service
  2. In the TFTP root folder field, specify which folder on the Synology NAS can be accessed by TFTP clients

TFTP

Install and Configure HTTP server

We also need a service to host our image repository; we can use FTP or HTTP, or NFS to host our image repository. Synology NAS comes with web hosting features. In Web Station, we will create a port-based virtual host to host the contents of our image repository.

Install the following packages from the Synology package center

  • Web Station
  • Apache HTTP Server 2.4

Create a virtual host

Open Web Station and go to Web Service Portal > Select Create Service Portal

Create Service

Select Virtual Host

Create Virtual Host

In the virtual host wizard

  • Select Port-based with protocol as HTTP and enter port number 8080
  • Select the Document root directory, which is the exact PXE location as TFTP
  • Select Apache HTTP Server as the back-end server
  • Click Create to save settings

HTTP Port based host

We need to enable simple directory browsing on the virtual host to access the contents of images and configuration files to perform PXE Boot.

In the Document root directory, create a file named .htaccess with the following content.

Options +Indexes

Navigate to IP:8080, and you should see a similar screen with files in the folder.

HTTP Server

PXE Boot Setup

Prepare Installation Repository

  • Download the ISO image file of the complete installation DVD
  • Create a directory named images/rhel/8.6 under the root directory of the TFTP/HTTP server
  • Mount the ISO image
  • Copy all the files from the ISO to the previously created directory on TFTP/HTTP server. You will need around 10GB of storage to copy all the files from the ISO to the local directory.
mount rhel-8.6-x86_64-dvd.iso /mnt
scp -pr /mnt/* nas-user@nas-address:/media/PXE/images/rhel/8.6

To perform the UEFI PXE Boot installation, we will need the following PXE boot files.

  • grubx64.efi provided by grub2-efi-x64 rpm
  • shimx64.efi provided by shim-x64 rpm
  • BOOTX64.EFI provided by shim-x64 rpm
cp -pr /mnt/BaseOS/Packages/grub2-efi-x64-2.02-81.el8.x86_64.rpm /tmp
cp -pr /mnt/BaseOS/Packages/shim-x64-15-11.el8.x86_64.rpm /tmp/

Extract the packages

cd /tmp
rpm2cpio shim-x64-15-11.el8.x86_64.rpm | cpio -dimv
rpm2cpio grub2-efi-x64-2.02-81.el8.x86_64.rpm | cpio -dimv

Copy the EFI boot images from the /tmp directory to the PXE root directory

scp /tmp/boot/efi/EFI/BOOT/BOOTX64.EFI nas-user@nas-address:/media/PXE
scp /tmp/boot/efi/EFI/centos/shimx64.efi nas-user@nas-address:/media/PXE
scp /tmp/boot/efi/EFI/centos/grubx64.efi nas-user@nas-address:/media/PXE

Add a configuration file named grub.cfg to the TFTP/HTTP root directory. We need initrd and vmlinuz files to load the Operating System until the hard disk and other interfaces are detected. In the grub.cfg take note of linuxefi and initrdefi. Please update it to TFTP/HTTP image directory location.

set timeout=30
menuentry 'Install RHEL 8.6 on T7910' {
    linuxefi images/rhel/8.6/images/pxeboot/vmlinuz inst.stage2=http://192.168.100.160:8080/images/rhel/8.6 quiet
    initrdefi images/rhel/8.6/images/pxeboot/initrd.img
}

Prepare kickstart file

Next, we will create our kickstart file for an unattended automated installation. I have used the kickstart configuration tool available at https://access.redhat.com/labs/kickstartconfig/ in the Red Hat Customer Portal Labs. This tool will walk you through basic configuration and allows you to download the resulting Kickstart file.

  • Create a new directory named ks under the root directory of the TFTP/HTTP server to store the kickstart file for the UEFI PXE Boot purpose
  • Copy the downloaded kickstart file into the previously created location
scp kickstart.cfg nas-user@nas-address:/media/PXE/ks
  • Update the grub.cfg to use the kickstart file during installation. For the inst.ks= boot option, specify kickstart location

The final grub.cfg will look like this:

set timeout=30
menuentry 'Install RHEL 8.6 on T7910' {
    linuxefi images/rhel/8.6/images/pxeboot/vmlinuz inst.ks=http://192.168.100.160:8080/ks/rhel8-t7910.cfg inst.stage2=http://192.168.100.160:8080/images/rhel/8.6 quiet
    initrdefi images/rhel/8.6/images/pxeboot/initrd.img
}

Perform PXE boot

We are ready to perform UEFI PXE Boot. The shortcut button to boot over the network may vary for different hardware, F12 on most common hardware.

If your UEFI PXE boot server configuration is accurate, then the TFTP files should acquire successfully.