2026-02-26 Clone a virtual machine from inside it
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I want to move my virtual machine from hoster edis.at to hoster
hosting.de. I'm using Debian stable/13/Trixie. Both of these are KVM
but I am just client, I don't have access to their management tools.
So how to go about it?

This page does not have an answer to the question. If you know what
I'm missing, let me know.

The two servers are sibirocobombus (source) and new-home (target).
My idea is that I will just copy the whole filesystem first, using
rsync. Many of the SQLite databases will be borked but that doesn't
matter. I make the target system bootable and reboot. Verify that this
works. This is where I'm stuck.

The plan is then to finish the migration of database-using services
since all the services using SQLite databases are borked. I shut down
all these services (GoToSocial, 3× Xobaque, The Lounge, possibly
others) on both the source and the target system. Then copy the whole
filesystem again, using rsync. This should be much faster sind almost
all the other files are unchanged. Then restart the services on the
target server and don't restart them on the source server.

On the source system:

    mkdir /mnt/src
    mount --options ro --bind / /mnt/src

On the target system:

    mkdir /mnt/target

On the source system again:

    rsync -aHAXSz \
      --delete \
      --info=progress2 \
      --numeric-ids \
      --exclude={"/dev/*","/proc/*","/sys/*","/tmp/*","/run/*","/mnt/*","/media/*","/lost+found","/etc/fstab","/etc/udev/rules.d/*","/etc/network/*","/lib/modprobe.d/*"} \
      /mnt/src/ new-home:/mnt/target/

On the target system:

    cd /mnt/target
    for i in /dev /dev/pts /proc /sys /run; do mount --bind $i .$i; done
    chroot /mnt/target
    update-grub
    update-initramfs -u
    exit
    reboot

This reboots me back into the original target system. /mnt/target
still exists and hasn't replaced the whole system, which is what I had
expected.

What do I need to do in order to make it happen?

mv all the files in /mnt/target into the correct place? After all,
/mnt/target doesn't contain /dev/*, /proc/*, /sys/*, /tmp/*,
/run/*, /mnt/*, /media/*, /lost+found, /etc/fstab,
/etc/udev/rules.d/*, /etc/network/*, /lib/modprobe.d/*. I should't
overwrite any of the directories with an empty directory in
/mnt/target, however.

What am I doing.

#Administration

2026-02-26. OK, I think the first step in getting there is that I
really have to start a recovery system for the target. And hosting.de
provides for this! So I switch into the recovery system.

Mount the target as /mnt/target and install rsync.

    mkdir mnt/target
    mount /sda/sda3 /mnt/target
    apt update
    apt install rsync

Now I can send over stuff again. Since I'm not overwriting /boot,
/initrd*, /vmlinuz* I kinda think I should just be able to reboot
this system.

Actually, no. Rebooting gets me the rescue system. Strange!

Well, I can go into the rescue system again and try the following,
based on Restoring from a tar Backup . Use lsblk to verify the device
names.

    # Restore the entire system (must boot from a rescue system)
    # 1. Mount the target partition
    mount /dev/sda3 /mnt
    # 2. Extract the backup to the target partition
    # skip, I guess
    # 3. Recreate necessary directories
    mkdir -p /mnt/{proc,sys,dev,run,tmp,mnt,media}
    # 4. Reinstall the bootloader
    mount --bind /dev /mnt/dev
    mount --bind /dev/pts /mnt/dev/pts
    mount --bind /proc /mnt/proc
    mount --bind /sys /mnt/sys
    mount --bind /run /mnt/run
    chroot /mnt
    grub-install /dev/sda
    update-grub
    exit

I sort of think I've done this before? We'll see. Also, where is
initramfs-update?

    root@rescue:/# grub-install /dev/sda
    Installing for i386-pc platform.
    Installation finished. No error reported.
    root@rescue:/# update-grub
    Generating grub configuration file ...
    Found linux image: /boot/vmlinuz-6.12.38+deb13-amd64
    Found initrd image: /boot/initrd.img-6.12.38+deb13-amd64
    Warning: os-prober will not be executed to detect other bootable partitions.
    Systems on them will not be added to the GRUB boot configuration.
    Check GRUB_DISABLE_OS_PROBER documentation entry.
    Adding boot menu entry for UEFI Firmware Settings ...
    done

The output looks OK. Rebooting still gets me the rescue system. Let's
try dashboard again.

Reset the system. The VNC terminal shows the hostname
"sibirocobombus"! Yay.

But I cannot ping the machine. Something broke. Some networking
configuration I should have copied from the rescue system, I assume.

Actually, if I use chroot /mnt I immediately lose network access. How
annoying.

I made some more changes, trying to find the key difference between
the two systems and eliminating it.

    cp /etc/resolv.conf /mnt/etc/resolv.conf
    rm /mnt/etc/systemd/network/*
    rm -rf /mnt/lib/systemd/network
    cp -r /lib/systemd/network /mnt/lib/systemd/network

By now, if I'm in the chroot, I have network access. I can run apt
update && apt upgrade, for example. But if I boot the system, I have
no network access.

With the web terminal, I'm looking at the startup screen and I see a
whole lot of services failing to start up. Not a problem, I thought.
Of course gotosocial is going to fail. But I also see conntrackd
fails to start as well. Uh. I think I need to disable the firewall
before restarting it?

2026-02-27. I'm still at a loss. I don't see how I can make the image
I have bootable on a different infrastructure. This feels very
uncomfortable. My system backup is not portable at all. 😓

So what I think I will have to do is reinstall Debian stable and bring
back every single service, one by one.

2026-02-28. I went into the rescue system, chroot into "my" system,
started the fail2ban server and unbanned all. Rebooted into "my"
system and still had the same problem. Terminal window in the web
dashboard of the hosting provider shows the login prompt showing "my"
hostname, but I can no longer reach it.

I guess it's time to rebuild it, using rsync selectively. Domain by
domain.

My notes are here: Paraelectrobombus.

2026-03-21. There are still some tasks left to do. Will this entire
thing take more than a month? Only time will tell. 😥