In a KVM VM, we cannot detect the disk by looking into /dev/disk/by-id :-(
We need a fallback for this environment. Maye we then just use /dev/vda? buster[~]$ ls -l /dev/disk/* /dev/disk/by-id: total 0 lrwxrwxrwx 1 root root 9 Feb 2 11:32 ata-QEMU_DVD-ROM_QM00003 -> ../../sr0 /dev/disk/by-partuuid: total 0 lrwxrwxrwx 1 root root 10 Feb 2 11:32 bfea682b-01 -> ../../vda1 /dev/disk/by-path: total 0 lrwxrwxrwx 1 root root 9 Feb 2 11:32 pci-0000:00:01.1-ata-2 -> ../../sr0 lrwxrwxrwx 1 root root 9 Feb 2 11:32 pci-0000:00:05.0 -> ../../vda lrwxrwxrwx 1 root root 10 Feb 2 11:32 pci-0000:00:05.0-part1 -> ../../vda1 lrwxrwxrwx 1 root root 9 Feb 2 11:32 virtio-pci-0000:00:05.0 -> ../../vda lrwxrwxrwx 1 root root 10 Feb 2 11:32 virtio-pci-0000:00:05.0-part1 -> ../../vda1 /dev/disk/by-uuid: total 0 lrwxrwxrwx 1 root root 10 Feb 2 11:32 81de4336-a35e-4615-b5e3-8d3c6dfb73b7 -> ../../vda1 -- viele Grüße Thomas