Replace Oracle Cloud Linux with Arch Linux remotely

convert2arch_x64.sh

[09/23/2023]

Refs:
1. http://mirror.cs.pitt.edu/archlinux/iso/2023.09.01/archlinux-bootstrap-2023.09.01-x86_64.tar.gz
2. https://dl-cdn.alpinelinux.org/alpine/v3.18/releases/x86_64/alpine-virt-3.18.0-x86_64.iso
3. https://wiki.alpinelinux.org/wiki/Replacing_non-Alpine_Linux_with_Alpine_remotely
4. https://wiki.archlinux.org/index.php/installation_guide#Configure_the_system

See also:
1. Convert to Debian   https://gist.github.com/zengxinhui/ee0ad6b7c7f99e2ead6cd0d2bd6641fd
2. Convert to arch x64 https://gist.github.com/zengxinhui/f328fdce54f5039689ee3aa4e91fc805
3. Convert to arch arm https://gist.github.com/zengxinhui/01afb43b8d663a4232a42ee9858be45e

Requirement:
  Console access.

# Prepare alpine linux, which can be configured to run from ram only.
# Alpine is leveraged to do the conversion.
# In any linux(ubuntu/debian/arch tested) become root first:
sudo su -
cd /tmp && wget https://dl-cdn.alpinelinux.org/alpine/v3.18/releases/x86_64/alpine-virt-3.18.0-x86_64.iso
dd if=alpine-virt-3.18.0-x86_64.iso of=/dev/sda && sync && reboot

# In Alpine with console:
# [Bring up networking]
ip li set eth0 up
udhcpc eth0
# [Setup SSH, answer RET, yes, RET]
setup-sshd
# [set temp password]
passwd
# [At this point it's easier to use SSH to copy & paste]

# [Per Ref #3. Move alpine to ram only]
mkdir /media/setup
cp -a /media/sda/* /media/setup
mkdir /lib/setup
cp -a /.modloop/* /lib/setup
/etc/init.d/modloop stop
umount /dev/sda
mv /media/setup/* /media/sda/
mv /lib/setup/* /.modloop/

# [Setup apk and bring in pacman]
setup-apkrepos
# [enable community]
vi /etc/apk/repositories

apk update
apk add dosfstools e2fsprogs cfdisk pacman arch-install-scripts

# [Disk partitioning & mounting]
# (use gpt table, set esp partition 15 size 256M), set root partition 1 size remaining)
# g, n, 15, RET, +256m, t, 1, n, RET, RET, RET, p, w
fdisk /dev/sda

ls /dev/sda*
# if sda1 or sda15 is missing, do "/etc/init.d/devfs restart"

mkfs.vfat /dev/sda15
mkfs.ext4 /dev/sda1

mount -t ext4 /dev/sda1 /mnt
mkdir /mnt/boot
mount /dev/sda15 /mnt/boot

# [1G ram is not enough to hold arch bootstrap. Use HDD for now.]
# [or technically you could just use the bootstrap tarball.]
mkdir /mnt/tmp
cd /mnt/tmp
wget http://mirror.cs.pitt.edu/archlinux/iso/2023.09.01/archlinux-bootstrap-2023.09.01-x86_64.tar.gz
tar xf archlinux-bootstrap-2023.09.01-x86_64.tar.gz
vi root.x86_64/etc/pacman.d/mirrorlist
arch-chroot root.x86_64/

  pacman-key --init
  pacman-key --populate archlinux
  
  # [Any other way than to mount again?]
  mount /dev/sda1 /mnt
  mount /dev/sda15 /mnt/boot
  pacstrap /mnt base linux
  genfstab -U /mnt >> /mnt/etc/fstab
  umount /mnt/boot
  umount /mnt
  exit

cd /; arch-chroot /mnt
# follow https://wiki.archlinux.org/index.php/installation_guide#Configure_the_system
# This is your arch root password. Choose carefully and remember it
passwd
pacman --noconfirm -S openssh grub efibootmgr vi
systemctl enable sshd
systemctl enable systemd-networkd

cat > ~/.ssh/authorized_keys << EOF
<your key here>
EOF

cat > /etc/systemd/network/en.network << EOF
[Match]
Name=en*

[Network]
DHCP=yes
DNSSEC=no
EOF

cat > /etc/systemd/network/eth.network << EOF
[Match]
Name=eth*

[Network]
DHCP=yes
DNSSEC=no
EOF

cat > /etc/resolv.conf << EOF
nameserver 1.1.1.1
nameserver 4.2.2.2
nameserver 8.8.8.8
EOF

# [EFI boot]
grub-install --target=x86_64-efi --efi-directory=/boot --bootloader-id=GRUB
vi /etc/default/grub
# Better console. Comparison below:
# GRUB_CMDLINE_LINUX_DEFAULT="loglevel=3 quiet"
# GRUB_CMDLINE_LINUX_DEFAULT="loglevel=3 console=ttyS0,115200"
# Or use perl/sed to replace
#   perl -pi.bak -e "s/quiet/console=ttyS0,115200/" /etc/default/grub
#   sed   -i.bak -e "s/quiet/console=ttyS0,115200/" /etc/default/grub
grub-mkconfig -o /boot/grub/grub.cfg
exit
reboot

These instructions worked for me. However, if I change the memory/number of CPUs after installation, the machine does not boot any more. It gets stuck in EFI prompt. Any ideas what could be causing this?

If you still have that problem, check this out.

Oddly enough, I use neboot. XYZ installs Arch directly, but systemboot fails after installing it in chroot according to the guide