Add image based approach

.gitignore

@@ -1,4 +1,3 @@
-/image
-/image.tar
 /mkosi.cache
 /mkosi.rootpw
+/mkosi.output

README.md

@@ -1,8 +1,14 @@
-# Reimage any VPS without KVM access 
+# Reimage any VPS without KVM access
+
+This repo conceptually shows how you can use systemctl soft-reboot to switch
+to a tmpfs root filesystem, which allows you to reformat and reinstall the
+OS preinstalled on your VPS with a different OS.
+
+## Tar based
 
 ```bash
-mkosi build
-rsync -zP image.tar root@ip:/root/
+mkosi --image=debian-tar build
+rsync -zP mkosi.output/debian-tar.tar root@ip:/root/
 ssh root@<ip>
 mkdir -p /run/nextroot
 cd /run/nextroot
@@ -13,3 +19,19 @@ ssh root@<ip>
 cryptsetup close root # Close old root cryptsetup mapper if you have that
 # Repartition hard drive and install your system
 ```
+
+## Image based
+
+```bash
+mkosi --image=debian-image build
+rsync -zP mkosi.output/debian-image.raw root@ip:/root/image.raw
+ssh root@<ip>
+mount -o remount,size=1700M /run
+cp image.raw /run/image.raw
+systemd-dissect -M /run/image.raw /run/nextroot
+cp /etc/ssh/ssh_host_* /run/nextroot/etc/ssh/
+systemctl soft-reboot
+ssh root@<ip>
+dmsetup remove root # Close old root cryptsetup mapper if you have that
+systemd-repart --copy-from --dry-run=no --empty=force /run/image.raw /dev/vda
+```

mkosi.images/arch-image.conf

@@ -0,0 +1,15 @@
+[Distribution]
+Distribution=arch
+
+[Content]
+Timezone=UTC
+Bootable=yes
+Packages=
+ linux
+ systemd
+ bash
+ pacman
+ openssh
+
+[Output]
+Format=disk

mkosi.images/debian-image.conf

@@ -0,0 +1,20 @@
+[Distribution]
+Distribution=debian
+Release=sid
+
+[Content]
+Timezone=UTC
+Bootable=yes
+Packages=
+ linux-image-amd64
+ systemd
+ systemd-boot
+ dbus
+ udev
+ bash
+ apt
+ openssh-server
+ systemd-resolved
+
+[Output]
+Format=disk

mkosi.conf → mkosi.images/debian-tar.conf

@@ -22,7 +22,6 @@ Packages=
  fdisk
  cryptsetup
  mkosi
-
 
 [Output]
 @Format=tar