Overview
This guide will explain how to configure your dhcp/pxe/tftp server infrastructure to support BIOS and UEFI-based systems network installation. This guide will mix PXELinux and grub technology. This combination seems the one that provides the best results when there is a need to deploy operating systems on UEFI or BIOS based systems. Because grub files are signed, this setup will also support UEFI and secure boot option enabled as well
The pxelinux bootloader will be used when BIOS Based systems need to be installed. Grub bootloader approach will be used when UEFI Systems needs to be deployed. The selection of the bootloader will be done automatically when the client boots. The boot process with include a packet information that will tell the PXE server which bootloader to use….
To deploy Ubuntu operating system through the network, necessary infrastructure and server services needs to be present on the network. DHCP, DNS, TFTP, Web and File services are needed in order to build up the needed PXE infrastructure.
Assumptions
The following assumptions have been made in order to have this scenario working
- Hyper-v platform is used to emulated UEFI based virtual machines
- VM Generation 2 will be used in order to have UEFI and SecureBoot option is Enabled
- You have internet connection in order to download additional necessary packages
- You have Ubuntu 18.04 Server ISO or installation files
- You have Ubuntu 18.04 Desktop ISO or installation files
Step by Step Guide
Step 0 – Install Ubuntu 18.04.2 Server Edition
In this post, we will be using Ubuntu 18.04.2 Server as the PXE server. Ubuntu 18.04.2 has been selected because this is a Long Term Service (LTS) release. This post will not explain how to install an Ubuntu server. When your installation is completed, move to the next step
Step 1 – Set a Static IP address on your Ubuntu Server
Ubuntu Server has no Desktop interface available by default. We will need to perform most of the actions through command lines. No fear, you will see it’s quite easy actually. To set a static ip address on your Ubuntu Server, you will need to edit the following file /etc/netplan/50-cloud-init.yaml.
To edit this file, issue the following command
sudo nano /etc/netplan/50-cloud-init.yaml
Replace the content of the file with the following one (you might need to update the information based on your infrastructure
network:
ethernets:
eth0:
dhcp4: no
addresses: [192.168.1.222/24]
gateway4: 192.168.1.1
nameservers:
addresses: [8.8.8.8,8.8.4.4]
version: 2
In order to apply the changes, we need to execute this command as well
sudo netplan apply
Finally, check that the ip address has been set correctly by issuing the following command
ip addr
Step 2 – Build up your PXE Server
In this post, we assume that the Ubuntu Server will be hosting all the necessary services needed to implement a proper PXE Infrastructure. To setup a pxe infra, we need to install the following packages
- dnsmasq (providing DHCP,DNS and TFTP services),
- apache web for storage purposes and
- NFS packages if you are planning to deploy Ubuntu Desktop through your PXE infrastructure.
Step 2.1 – Install apache web server
To install the apache package, you will issue the following command
sudo apt-get install apache2
Step 2.2 – Install NFS packages
NFS packages will provide file services capabilities. To install the nfs packages, execute the following commands
sudo apt-get install nfs-kernel-server
Step 2.3 – Install dnsmasq packages
To install the dnsmasq package, you will issue the following command
sudo apt-get dnsmasq
Step 3 – Create the TFTP Folder Structure
We will create a folder called tftp at root of the filesystem (/tftp). Within this folder, the following structure will be create
tftp |-bios |-boot |-grub
To create this structure, you will need to execute the following commands
sudo mkdir /tftp sudo mkdir /tftp/bios sudo mkdir /tftp/boot sudo mkdir /tftp/grub
Step 4 – Upload source files on your PXE Server
Because you are using the Apache Web server, we will be copying all sources files under /var/www/html directory. We will copy the iso files contents of Ubuntu 18.04 Desktop and Ubuntu Server under this location. We will create the following structure first
sudo mkdir /var/www/html/bionic/server sudo mkdir /var/www/html/bionic/desktop
You can obviously add other version of Ubuntu files and your structure could look like the following
var
|-www
|-html
|-bionic
|-server
|-desktop
|-Disco
|-server
|-desktop
So, mount your iso file into your Ubuntu server. To mount it, issue the following command
sudo mount /dev/sr0 /media
Copy the files from the iso image into the correct directory. You can use the following syntax to perform the operation
sudo cp -rf <%Your Path To Install Files%>/* /var/www/html/server/bionic
When the copy is finished, unmount the iso/DVD image from your machine by issuing the following command
sudo umount /media
Repeat the operation for each operating system sources files you want to copy on your PXE Server
Step 5 – Configuring your NFS Server Settings
Since our folder structure is ready, we can start configuring the different services that are used by the PXE server. To ensure that our directory structure is accessible through the network and through the nfs protocol, we will need to edit the following file by issuing the following command
sudo nano /etc/exports
Insert at the bottom of the file, the path where you have stored your installation files, which subnet can access it and which kind of right you want to grant. In our scenario, we want to grant access to the following directory /var/www/html/bionic/desktop through the network subnet 192.168.1.0/24 and we are granting read only access (ro). So, at the end of the file, we would add the following line
/var/www/html/bionic/desktop 192.168.1.0/24(ro)
When this has been done, it’s time to restart the nfs service. To do that, you simply execute the following command
sudo systemctl restart nfs-kernel-server
Step 6 – Configuring the dnsmasq services
Almost there ! Now, we need to configure the dnsmasq service which will provide the glue between the different services. dnsmasq configuration file will be used to provide the necessary information to the pxe client when it boots. This file will dictate where to look for pxe bootloader based on the client architecture (uefi or bios). So, let’s edit the /etc/dnsmasq.conf file and at the bottom add the following information
To edit the configuration file, issue the following command
sudo nano /etc/dnsmasq.conf
Copy and update the following information at the bottom of the file
Note : You will need to modify it accordingly to reflect your own infrastructure
#Interface information #--use ip addr to see the name of the interface on your system interface=eth0,lo bind-interfaces domain=c-nergy.local #-------------------------- #DHCP Settings #-------------------------- #-- Set dhcp scope dhcp-range=192.168.1.160,192.168.1.200,255.255.255.0,2h #-- Set gateway option dhcp-option=3,192.168.1.1 #-- Set DNS server option dhcp-option=6,192.168.1.1 #-- dns Forwarder info server=8.8.8.8 #----------------------# # Specify TFTP Options # #----------------------# #--location of the pxeboot file dhcp-boot=/bios/pxelinux.0,pxeserver,192.168.1.150 #--enable tftp service enable-tftp #-- Root folder for tftp tftp-root=/tftp #--Detect architecture and send the correct bootloader file dhcp-match=set:efi-x86_64,option:client-arch,7 dhcp-boot=tag:efi-x86_64,grub/bootx64.efi
To have the change applied to your system, you will need to restart the dnsmasq service. To perform such task, you will execute the following command
sudo systemctl restart dnsmasq
Then, you should check that the dnsmasq is started correctly and that no errors are reported by issuing the command
sudo systemctl status dnsmasq
Step 7 – Uploading all the necessary files in your TFTP folder Structure
We are almost ready ! Now, we need to get the necessary file placed in your tftp folder in order to have pxe capability.
Step 7.1 – populate bios folder
In the /tftp/bios folder, we will place the pxelinux files needed. To obtain the pxelinux files, you can download the files from the following url (https://mirrors.edge.kernel.org/pub/linux/utils/boot/syslinux/Testing/6.04/). Then, you can copy the following files from pxelinux sources files to /tftp/bios folder
sudo cp <%your download location%>/bios/com32/elflink/ldlinux/ldlinux.c32 /tftp/bios/ldlinux.c32 sudo cp <%your download location%>/bios/com32/libutil/libutil.c32 /tftp/bios/libutil.c32 sudo cp <%your download location%>/bios/com32/menu/menu.c32 /tftp/bios/menu.c32 sudo cp <%your download location%>/bios/com32/menu/vesamenu.c32 /tftp/bios/vesamenu.c32 sudo cp <%your download location%>/bios/core/pxelinux.0 /tftp/bios/pxelinux.0 sudo cp <%your download location%>/bios/core/lpxelinux.0 /tftp/bios/lpxelinux.0
You will also need to create a symbolic link to the /tftp/boot folder. You will need to issue the following command
sudo ln -s /tftp/boot /tftp/bios/boot
We will also need to create the folder called pxelinux.cfg under the /tftp/bios folder. Inside this folder, we will create an empty file called default. This file control the pxelinux behavior. We will populate it with the following code
DEFAULT menu.c32
MENU TITLE ULTIMATE PXE SERVER - By Griffon - Ver 1.0
PROMPT 0
TIMEOUT 0
MENU COLOR TABMSG 37;40 #ffffffff #00000000
MENU COLOR TITLE 37;40 #ffffffff #00000000
MENU COLOR SEL 7 #ffffffff #00000000
MENU COLOR UNSEL 37;40 #ffffffff #00000000
MENU COLOR BORDER 37;40 #ffffffff #00000000
LABEL Ubuntu Server 18.04
kernel /boot/server/linux
append vga=788 initrd=/boot/server/initrd.gz
LABEL Ubuntu Desktop 18.04
kernel /boot/casper/vmlinuz
append nfsroot=192.168.1.150:/var/www/html/desktop/bionic netboot=nfs ro file=/cdrom/preseed/ubuntu.seed boot=casper initrd=boot/casper/initrd.lz systemd.mask=tmp.mount --
Save it
You are ready to move to the next section
Step 7.2 – Populate boot folder
In this step, we need to place the correct bootloader in order for the installation process to start accordingly. Under the /tftp/boot folder, we will create 2 sub folders to make a distinction between the server and the desktop bootloader files. So the folder structure will look like the following
tftp
|-bios
|-boot
| - server
| - casper
|-grub
We will copy the necessary files from the /var/www/html location. Issue the following commands to copy the necessary files to the correct location
sudo cp /var/www/html/bionic/desktop/casper/vmlinuz /tftp/boot/casper sudo cp /var/www/html/bionic/desktop/casper/initrd.lz /tftp/boot/casper
sudo cp /var/www/html/bionic/server/install/netboot/ubuntu-installer/amd64/linux /tftp/boot/server sudo cp /var/www/html/bionic/server/install/netboot/ubuntu-installer/amd64/initrd.gz /tftp/boot/server
Step 7.3 – Populate grub folder
Finally, we need to populate the grub folder. This folder contains the files that are needed to boot uefi systems. So, in your system, you will execute the following commands. The commands below basically will download the necessary signed bootloader files and grub files needed by PXE server and extract the contents on their dedicated folders (shim and grub)
apt-get download shim.signed dpkg -x <%name of the deb package%> shim apt-get download grub-efi-amd64-signed dpkg -x <%name of the deb package%> grub
When this is done, we can simply copy the needed file into the tftp boot folder. So, execute the following commands. Change the path accordingly based on your settings…
sudo cp ~/grub/<%name of package%>/usr/lib/grub/x86_64-efi-signed/grubnetx64.eif.signed /tftp/grubx64.efi sudo cp ~/shim/<%name of package%>/usr/lib/shim/shimx64.efi.signed /tftp/grub/bootx64.efi
Finally, we will copy two additional files from the source iso image. They will server as base for the next step. So, execute the following commands
sudo cp /var/www/html/bionic/server/boot/grub/grub.cfg /tftp/grub/ sudo cp /var/www/html/bionic/server/boot/grub/font.pf2 /tftp/grub/
Step 7.4 – Create/update the grub.cfg
We are almost done ! Now, we need to create also a boot menu and get the proper option available and working. The grub boot loader reads information from the grub.cfg file. If you have followed this step by step guide, the content of the grub.cfg file should look like this
if loadfont /grub/font.pf2 ; then
set gfxmode=auto
insmod efi_gop
insmod efi_uga
insmod gfxterm
terminal_output gfxterm
fi
set menu_color_normal=white/black
set menu_color_highlight=black/light-gray
set timeout=5
menuentry "Ubuntu Server 18.04" {
set gfxpayload=keep
linux boot/server/linux ip=dhcp rw
initrd boot/server/initrd.gz
}
menuentry "Ubuntu Desktop 18.04" {
set gfxpayload=keep
linux /boot/casper/vmlinuz ip=dhcp nfsroot=192.168.1.150:/var/www/html/bionic/desktop netboot=nfs ro file=/cdrom/preseed/ubuntu.seed boot=casper systemd.mask=tmp.mount --
initrd /boot/casper/initrd.lz
}
Step 8 – Test your configuration
This is the fun part ! If everything is working as expected, when you boot your Bios client, you should see the pxelinux boot loader showing up. As you can see on the screenshot below, we have customized a little bit the look’n feel of the boot menu in order to match to the grub boot menu.
Click on picture for better resolution
Doing the same for UEFI computers, you should see a boot menu similar to the following..
Click on picture for better resolution