doarch.sh

#!/bin/bash
apt-get -y update && apt-get -y install haveged && systemctl start haveged

disksize=$(lsblk -bndo SIZE /dev/vda)
partm=$(($disksize/1048576-1024))

cat <<EOF | sfdisk /dev/vda
label: dos
size=${partm}M type=83
type=82
EOF

mkfs.ext4 /dev/vda2
mount /dev/vda2 /mnt

curl -L https://sgp.mirror.pkgbuild.com/iso/latest/archlinux-bootstrap-2019.04.01-x86_64.tar.gz | tar -C /mnt --strip-components=1 -zx

cat <<EOF > /mnt/chroot.sh
pacman-key --init && pacman-key --populate archlinux
echo 'Server = https://sgp.mirror.pkgbuild.com/\$repo/os/\$arch' > /etc/pacman.d/mirrorlist
pacman -Sy
mkfs.ext4 /dev/vda1
mount /dev/vda1 /mnt
pacstrap /mnt base haveged openssh grub
genfstab -U /mnt >> /mnt/etc/fstab
cp /inst.sh /mnt/root/inst.sh
arch-chroot /mnt bash /root/inst.sh
EOF

cat <<EOF > /mnt/inst.sh
ln -sf /usr/share/zoneinfo/Asia/Singapore /etc/localtime
hwclock --systohc
echo en_SG.UTF-8 UTF-8 > /etc/locale.gen
locale-gen
echo LANG=en_SG.UTF-8 > /etc/locale.conf
echo $HOSTNAME > /etc/hostname
grub-install /dev/vda
grub-mkconfig -o /boot/grub/grub.cfg
echo 'PermitRootLogin prohibit-password' >> /etc/ssh/sshd_config
echo 'DNSSEC=no' >> /etc/systemd/resolved.conf
echo 'DNSOverTLS=no' >> /etc/systemd/resolved.conf
umount /etc/resolv.conf
ln -sf /run/systemd/resolve/stub-resolv.conf /etc/resolv.conf
systemctl enable sshd haveged systemd-networkd systemd-resolved
passwd
EOF

/mnt/usr/bin/arch-chroot /mnt bash /chroot.sh

mkdir -p /mnt/mnt/etc/systemd/network
cat <<EOF > /mnt/mnt/etc/systemd/network/ens3.network
[Match]
Name=ens3

[Network]
$(ip addr show scope global | grep -E '^\s+inet' | sed -e 's/^[[:space:]]*inet[0-9]* /Address=/' | cut -d' ' -f1)
Gateway=$(ip route get 1.0.0.1 | grep -o -E 'via [0-9\.]+' | cut -d' ' -f2)
Gateway=$(ip route get 2606:4700:4700::1111 | grep -o -E 'via [0-9a-f:]+' | cut -d' ' -f2)
DNS=1.0.0.1
DNS=1.1.1.1
DNS=2606:4700:4700::1111
DNS=2606:4700:4700::1001
EOF

cp -R /root/.ssh /mnt/mnt/root/.ssh