Replace Oracle Cloud Linux with Arch Linux ARM remotely

convert2arch_arm.sh

[09/23/2023]

Refs:
1. http://os.archlinuxarm.org/os/ArchLinuxARM-aarch64-latest.tar.gz
2. https://dl-cdn.alpinelinux.org/alpine/v3.18/releases/aarch64/alpine-virt-3.18.0-aarch64.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
5. https://archlinuxarm.org/platforms/armv8/generic

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/aarch64/alpine-virt-3.18.0-aarch64.iso
dd if=alpine-virt-3.18.0-aarch64.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]
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 findmnt 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

cd /mnt && wget http://os.archlinuxarm.org/os/ArchLinuxARM-aarch64-latest.tar.gz
bsdtar -xpf /mnt/ArchLinuxARM-aarch64-latest.tar.gz -C /mnt
genfstab -U /mnt >> /mnt/etc/fstab

cd /; arch-chroot /mnt/
# This is your arch root password. Choose carefully and remember it
# do the same for user `alarm` if you prefer to use that account and lots of `sudo`
passwd
cat > ~/.ssh/authorized_keys << EOF
<your key here>
EOF

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

pacman-key --init
pacman-key --populate archlinuxarm
pacman --noconfirm -Syu grub efibootmgr vi

# [EFI boot]
grub-install --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

The disk is partiioned according to fdisk

Device       Start      End  Sectors  Size Type
/dev/sda1  1050624 97675263 96624640 46.1G Linux filesystem
/dev/sda15    2048  1050623  1048576  512M EFI System

but /dev/sda1 does not show under /dev when doing ls /dev only /dev/sda and /dev/sda15

so for whatever reason, the node device for /dev/sda1 was not present.... fixed it with:

mknod /dev/sda1 b 8 1

Thanks for the instructions.

If anyone runs into the problem of not being able to ssh into the machine after changing CPU count, try going into Oracle's Cloud Console. There, you should find yourself in the EFI Shell as grub couldn't be booted (at least in my case).

Enter map to get the mapping table. First entry should be FS0, so enter FS0: to change directory to the FS0 device. You should now be on the boot partition. You should be able to cd EFI/GRUB, and ls to confirm that there is the grubaa64.efi. Enter grubaa64.efi to boot grub/Arch.

You can now either login through that Console or ssh into your machine and run grub-install --efi-directory=/boot/efi --bootloader-id=GRUB again. It should now reboot as usual.

Not really sure what exactly causes it, some part isn't persistent through CPU count/memory amount changes.

has anyone had luck installing fedora cloud on this?

just a doubt, I have to create an instance with Oracle Linux 8, is that it?

The only change I would make is to switch ext4 to BTRFS + ZSTD

Followed this guide and with a few tiny mods got Arch up and running. I had one or a few reboots in the process.

When I issued poweroff - Arch powered off but the instance said Running in my Oracle account. I stopped the instance, and the next time I tried running it - it wouldn't boot up, no pings, no SSH. The console shows me Shell> only.

Is the intention here that Alpine is running 24/7 and when it stops - your Arch OS is gone or did I just miss a step somewhere and it's an easy recover?

---

Played with it for a while. I can get to the UEFI shell and launch EFI/GRUB/grubaa64.efi directly, but this is not a long-term solution. Right now I have a functioning system but whenever I need to power it up I need to create a serial connection and launch OS manually. I even created /boot/startup.nsh but that didn't help