Thinks Password Resetter

Bootable CD ISO image, that automatically resets a VM password for the root user and shuts down the VM.

Usage

There is no interaction with the CD by design. Attach it to a VM, power up the VM (ensuring the CD device has boot priority in the BIOS), and it'll reset the root password to "qqq".

Building

Build the docker image

$ cd passreset-docker
$ linuxkit pkg build -org thinkst .
...
Tagging thinkst/passreset:cec15b5fd2a0200a3b21d3550db4097015cbbfe6-amd64 as thinkst/passreset:cec15b5fd2a0200a3b21d3550db4097015cbbfe6

Build the ISO CD

$ linuxkit build -format iso-bios passreset.yml

Parameterizing the password and disk

Add rootpartition and rootpassword in the cmdline of passreset.yml to specify which disk and password should be used. For example:

# passreset.yml
...
 cmdline: "console=tty0 console=ttyS0 console=ttyAMA0 rootpartition=/dev/sda1 rootpassword=qqq"
 ...

Shrinking the image size

The image using the default kernel includes a bunch of extra code, such as extensive network protocol support. Since that's unneeded, you can shrink the final ISO size by compiling a custom Linux kernel following LinuxKit's documentation. We offer two files to assist in the kernel/ subdirectory of this repo.

Follow these steps to get a smaller kernel image:

$ git clone https://github.com/linuxkit/linuxkit/
$ cp kernel/* linuxkit/kernel/
$ cd linuxkit/kernel
$ make build_5.4.x

The docs also describe how to drop into a make menuconfig session, to further strip the config.

The reduced kernel's tag can be used in the passreset-reduced-kernel.yml file to produce a smaller ISO:

$ linuxkit build -format iso-bios passreset-reduced-kernel.yml