CentOS 7: Install PXE Boot server for automated install

This article will run PXE Boot server for automated install, and automatically install CentOS 7 on client which is connected to PXE Boot server via network. You must make client memory be rather than 1536MB.

1 Install PXE Boot server

The following script will install PXE Boot server. Change the variables to your environment.

  • SERVER_IPADDR is IP adress of PXE Boot server.
  • DHCP_SUBNET is network address for DHCP.
  • DHCP_NETMASK is subnet for DHCP.
  • DHCP_DOMAIN is domain for DHCP.
  • DHCP_DNS is DNS for DHCP.
  • DHCP_ROUTER is gateway for DHCP.
  • DHCP_CLIENT_HOSTNAME is hostname of client.
  • DHCP_CLIENT_IPADDR is IP address of client.
  • DHCP_CLIENT_MACADDR is MAC address of client.
  • KICKSTART_LANGUAGE is language for Kickstart.
  • KICKSTART_KEYMAP is keyboard layout for Kickstart.
  • KICKSTART_TIMEZONE is time zone for Kickstart.
  • MIRROR_URL is repository URL for network installation.

Preseed runs the following.

  • Set root user password to "centos".
  • Create user which name is "centos" and password is "centos".
  • Password is hashed with this.
  • Install packages for GNOME desktop environment.
  • This article creates centos-7-ks.cfg. But you can use /root/anaconda-ks.cfg by making "cdrom" to comment out.
#!/bin/sh

set -e

# Change the following variable to yours.
[ -z "${SERVER_IPADDR}" ] && \
  SERVER_IPADDR=$(hostname -I | awk '{ print $1 }')
[ -z "${DHCP_SUBNET}" ] && DHCP_SUBNET=192.168.11.0
[ -z "${DHCP_NETMASK}" ] && DHCP_NETMASK=255.255.255.0
[ -z "${DHCP_DOMAIN}" ] && DHCP_DOMAIN=hiroom2.com
[ -z "${DHCP_DNS}" ] && DHCP_DNS="192.168.11.2, 192.168.11.1"
[ -z "${DHCP_ROUTER}" ] && DHCP_ROUTER=192.168.11.1
[ -z "${DHCP_CLIENT_HOSTNAME}" ] && \
  DHCP_CLIENT_HOSTNAME=centos-7-pxeboot-client
[ -z "${DHCP_CLIENT_IPADDR}" ] && DHCP_CLIENT_IPADDR=192.168.11.254
[ -z "${DHCP_CLIENT_MACADDR}" ] && DHCP_CLIENT_MACADDR=52:54:00:5e:7a:a4
[ -z "${KICKSTART_LANGUAGE}" ] && KICKSTART_LANGUAGE=en_US.UTF-8
[ -z "${KICKSTART_KEYMAP}" ] && KICKSTART_KEYMAP=jp
[ -z "${KICKSTART_TIMEZONE}" ] && KICKSTART_TIMEZONE=Asia/Tokyo

# The mirror.centos.org is slow. You should use your country mirror server.
# e.g.) MIRROR_URL=http://ftp.riken.jp/Linux/centos/7/os/x86_64
[ -z "${MIRROR_URL}" ] && \
  MIRROR_URL=http://mirror.centos.org/centos-7/7/os/x86_64

tftp_server_install()
{
  sudo yum install -y tftp-server
  sudo firewall-cmd --add-service=tftp --permanent
  sudo firewall-cmd --reload
  sudo systemctl enable tftp
  sudo systemctl restart tftp
}

dhcp_install()
{
  sudo yum install -y dhcp

  cat <<EOF | sudo tee /etc/dhcp/dhcpd.conf
subnet ${DHCP_SUBNET} netmask ${DHCP_NETMASK} {
  option domain-name "${DHCP_DOMAIN}";
  option domain-name-servers ${DHCP_DNS};
  option routers ${DHCP_ROUTER};
  next-server ${SERVER_IPADDR};
  filename "pxelinux.0";
}

host ${DHCP_CLIENT_HOSTNAME} {
  hardware ethernet ${DHCP_CLIENT_MACADDR};
  fixed-address ${DHCP_CLIENT_IPADDR};
}
EOF

  sudo firewall-cmd --add-service=dhcp --permanent
  sudo firewall-cmd --reload
  sudo systemctl enable dhcpd
  sudo systemctl restart dhcpd
}

nfs_utils_install()
{
  sudo yum install -y nfs-utils
  sudo firewall-cmd --add-service=nfs --permanent
  sudo firewall-cmd --reload
  sudo systemctl enable nfs
  sudo systemctl restart nfs

  sudo mkdir /var/lib/nfsroot
  cat <<EOF | sudo tee /etc/exports
/var/lib/nfsroot *(rw,sync,no_root_squash,no_subtree_check)
EOF
  sudo exportfs -ra
}

syslinux_install()
{
  sudo yum install -y syslinux

  cd /var/lib/tftpboot
  sudo cp /usr/share/syslinux/pxelinux.0 .
  sudo cp -a /usr/share/syslinux .

  sudo wget -q ${MIRROR_URL}/isolinux/initrd.img
  sudo wget -q ${MIRROR_URL}/isolinux/vmlinuz

  sudo mkdir pxelinux.cfg
  cat <<EOF | sudo tee pxelinux.cfg/default
path syslinux
include menu.cfg
default syslinux/vesamenu.c32
prompt 0
timeout 50
EOF

  cat <<EOF | sudo tee menu.cfg
menu hshift 13
menu width 49
menu margin 8
menu tabmsg

menu title automated install boot menu
label centos-7-automated-install
  menu label ^CentOS 7 automated install
  kernel vmlinuz
  append vga=788 initrd=initrd.img ip=dhcp inst.repo=${MIRROR_URL} \
    ks=nfs:${SERVER_IPADDR}:/var/lib/nfsroot/centos-7-ks.cfg
menu end
EOF
}

kickstart_install()
{
  root_passwd=$(python -c "
import crypt
print(crypt.crypt(\"centos\", crypt.mksalt(crypt.METHOD_SHA512)))
")
  user_passwd=$(python -c "
import crypt
print(crypt.crypt(\"centos\", crypt.mksalt(crypt.METHOD_SHA512)))
")

  cat <<EOF | sudo tee /var/lib/nfsroot/centos-7-ks.cfg
%pre
if [ -b /dev/vda ]; then
  echo "ignoredisk --only-use=vda" > /tmp/drive-ks.cfg
  echo "bootloader --location=mbr --boot-drive=vda" >> /tmp/drive-ks.cfg
else
  echo "ignoredisk --only-use=sda" > /tmp/drive-ks.cfg
  echo "bootloader --location=mbr --boot-drive=sda" >> /tmp/drive-ks.cfg
fi
%end

%post
# Using "firstboot --disable" does not work correctly?
systemctl disable initial-setup-graphical
systemctl disable initial-setup-text
%end

%include /tmp/drive-ks.cfg
auth --enableshadow --passalgo=sha512
graphical
firstboot --disable
eula --agreed
keyboard --vckeymap=${KICKSTART_KEYMAP} --xlayouts='${KICKSTART_KEYMAP}'
lang ${KICKSTART_LANGUAGE}
network --bootproto=dhcp --device=eth0 --ipv6=auto --activate
network --hostname=${DHCP_CLIENT_HOSTNAME}
rootpw --iscrypted ${root_passwd}
timezone ${KICKSTART_TIMEZONE} --isUtc
user --groups=wheel --name=centos --password=${user_passwd} --iscrypted
xconfig  --startxonboot
autopart --type=lvm
clearpart --none --initlabel
reboot

%packages
@^gnome-desktop-environment
@base
@core
@desktop-debugging
@development
@dial-up
@directory-client
@fonts
@gnome-apps
@gnome-desktop
@guest-agents
@guest-desktop-agents
@input-methods
@internet-browser
@java-platform
@multimedia
@network-file-system-client
@networkmanager-submodules
@print-client
@x11
%end

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

pxeboot_main()
{
  tftp_server_install
  dhcp_install
  nfs_utils_install
  syslinux_install
  kickstart_install
}

pxeboot_main

2 Install CentOS 7 automatically

This article installs CentOS 7 on virtual machine on KVM. Virtual machine on VirtualBox and real machine too can be installed CentOS 7 automatically with enabling network boot. Please check your BIOS setting.

Enable "NIC" of "Boot device order" with virt-manager. If CDROM is not empty or Disk is already installed some OS, you need to change order in order to NIC be top.

0001_BootDeviceOrder.png

iPXE sends DHCP requests, receives DHCP response from PXE Boot server, download and run boot image.

0002_iPXE.png

syslinux's menu is displayed. After 5 seconds, "CentOS 7 automated install" will be selected automatically.

0003_syslinux.png

Automated install is started.

0004_AutomatedInstall.png

Virtual machine is rebooted automatically when automated install is completed. Installed CentOS 7 is started.

0005_AutomatedInstalledCentOS.png