Automated CentOS 7 Deployment with UEFI PXE and Kickstart

Security and Package Manager Setup

Disable firewalld and SELinux enforcement to avoid network blocks during provisioning. Configure the Alibaba Cloud mirror for faster package retrieval.

systemctl disable --now firewalld
setenforce 0

cp /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
yum clean all && yum makecache

Service Layer Installation

Install and enable the mandatory network provisioning services: Apache HTTPD, TFTP, DHCP, and the xinetd super-server.

yum -y install httpd tftp-server dhcp xinetd
systemctl enable httpd tftp dhcp xinetd --now

TFTP Service Definition

Create the TFTP configuration within xinetd. The server root is set to /var/lib/tftpboot and listens on UDP.

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

DHCP Server Configuration

Define the subnet, dynamic addres pool, and point clients to the PXE boot loader and server IP.

# /etc/dhcp/dhcpd.conf
ddns-update-style none;

filename "bootx64.efi";
next-server 10.0.17.100;

subnet 10.0.17.0 netmask 255.255.255.0 {
  range 10.0.17.200 10.0.17.230;
  option routers 10.0.17.2;
  option domain-name-servers 114.114.114.114;
}

HTTP Repository Preparation

Simplify the default HTTP welcome page and mount the CentOS ISO content at a dedicated directory.

cat > /etc/httpd/conf.d/welcome.conf << 'WELCOME'
<Directory /usr/share/httpd/noindex>
    AllowOverride None
    Require all granted
</Directory>
WELCOME

mkdir -p /var/www/html/centos
mount -o loop /var/www/html/centos.iso /var/www/html/centos

UEFI Boot Artifacts

Copy kernel and initrd from the mounted image, then generate a standalone GRUB EFI binary with the necessary network and filesystem modules.

cp /var/www/html/centos/images/pxeboot/initrd.img /var/lib/tftpboot/initrd
cp /var/www/html/centos/images/pxeboot/vmlinuz /var/lib/tftpboot/vmlinuz
cp /var/www/html/centos/EFI/BOOT/grubx64.efi /var/lib/tftpboot/grubx64.efi

yum install -y grub2-efi-x64 shim-x64 grub2-efi-x64-modules

grub2-mkstandalone -d /usr/lib/grub/x86_64-efi/ \
  -O x86_64-efi \
  --modules="tftp net efinet linux part_gpt efifwsetup" \
  -o /var/lib/tftpboot/bootx64.efi

chmod 777 /var/lib/tftpboot

Boot Menu Definition

Create the GRUB configuration that loads essential video and filesystem drivers and defines the installation entry. The target ISO and Kickstart file are fetched over HTTP.

# /var/lib/tftpboot/grub.cfg
function load_video {
  insmod efi_gop
  insmod efi_uga
  insmod video_bochs
  insmod video_cirrus
  insmod all_video
}

load_video
set gfxpayload=keep
insmod gzio
insmod part_gpt
insmod ext2

set timeout=5

menuentry 'CentOS 7 Unattended Install' --class fedora --class gnu-linux --class gnu --class os {
        set gfxpayload=keep
        linuxefi (tftp)/vmlinuz ip=dhcp inst.repo=http://10.0.17.100/centos ks=http://10.0.17.100/ks.cfg
        initrdefi (tftp)/initrd
}

Kickstart Answer File

Install the graphical Kickstart configuration tool and set up a local repository file pointing to the mounted source.

yum install -y system-config-kickstart

cat > /etc/yum.repos.d/development.repo << EOF
[development]
name=development
baseurl=file:///var/www/html/centos
gpgcheck=0
EOF

The ks.cfg file defines a fully automated installation: disk partitioning with LVM on /dev/sda, UEFI boot, disabled firewall, DHCP networking, and a post-installation script that switches the package sources to Alibaba Cloud mirrors and a local repo.

#platform=x86, AMD64, or Intel EM64T
#version=DEVEL

install
graphical
auth --useshadow  --passalgo=sha512
firewall --disabled
firstboot --enable
ignoredisk --only-use=sda
keyboard --vckeymap=us --xlayouts='us'
lang en_US.UTF-8
network  --bootproto=dhcp --device=link --activate
network  --hostname=pxe-client.local
timezone Asia/Shanghai --isUtc
rootpw --plaintext changeme123
selinux --permissive
services --enabled="chronyd"
reboot
url --url="http://10.0.17.100/centos"
user --name=operator --password=$6$R3b.LTR/NkobA1Sv$quYMCv3b6czowr6o6y9Yz53yg/DR9PSQxlUMJCD.GnbMewAPeFePAzL7pQQ4HEW.LdGjJw4OUnPCVWjg12UKV/ --iscrypted --gecos="operator"
xconfig  --startxonboot
bootloader --location=mbr --boot-drive=sda
zerombr
clearpart --all --initlabel
bootloader --location=mbr --boot-drive=sda

part /boot/efi --fstype="efi" --ondisk=sda --size=200 --fsoptions="umask=0077,shortname=winnt"
part /boot --fstype="xfs" --ondisk=sda --size=1024
part pv.01 --fstype="lvmpv" --ondisk=sda --grow
volgroup vg_centos --pesize=4096 pv.01
logvol swap --fstype="swap" --size=2048 --name=swap --vgname=vg_centos
logvol / --fstype="xfs" --grow --name=root --vgname=vg_centos

%post --log=/root/ks-post.log
/bin/cp /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
/bin/cat > /etc/yum.repos.d/CentOS-Base.repo << 'BASE'
[base]
name=CentOS-$releasever - Base - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7

[updates]
name=CentOS-$releasever - Updates - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/updates/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7

[extras]
name=CentOS-$releasever - Extras - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/extras/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7
BASE

/bin/mkdir -p /etc/yum.repos.d/bak
/bin/mv /etc/yum.repos.d/CentOS-* /etc/yum.repos.d/bak 2>/dev/null
/bin/cat > /etc/yum.repos.d/local.repo << 'LOCAL'
[local]
name=Local Repository
baseurl=http://10.0.17.100/centos
enabled=1
gpgcheck=0
LOCAL

yum clean all
yum makecache
%end

%packages
@base
@core
chrony
%end

%addon com_redhat_kdump --disable --reserve-mb='auto'
%end

The system reboots upon completion.

Tags: CentOS7 PXE kickstart UEFI DHCP

Posted on Fri, 30 Oct 2026 16:09:27 +0000 by el_quijote

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