dmverity-vhd

README

dmverity-vhd

Takes an OCI image locator and an output directory and converts the layers that make up the image into a series of VHDs in the output directory. One VHD will be created per image layer.

VHDs are named with the name of the layer SHA.

Each layer contains dm-verity information that can be used to ensure the integrity of the created ext4 filesystem. All VHDs have a layout of:

• ext4 filesystem
• dm-verity superblock
• dm-verity merkle tree
• VHD footer

The output is deterministic except for the UUIDs embedded in the VHD footer and the dm-verity superblock. Both UUIDs are currently seeded using a random number generator.

Example usage

Create VHDs:

dmverity-vhd create -i alpine:3.12 -o alpine_3_12_layers

Compute root hashes:

dmverity-vhd --docker roothash -i alpine:3.12

Compute root hashes with tarball:

dmverity-vhd --tarball /path/to/tarball.tar roothash -i alpine:3.12