[Bug 556167] Re: vmbuilder uses parted to create disk images, which leads to broken sector counts (cannot use grub2 on disk images created by vmbuilder/parted)

[Kees Cook]

The problem is that parted treats local files (as used by vmbuilder)
differently from "actual" disk files, and changes the sector size
accordingly (without an option to change it). As a result, the partition
start locations are too small for grub2 to install. I had originally
reproduced this by using vmbuilder to install Ubuntu, and then
attempting to update to grub2, which would fail, since there wasn't
enough room.

My previously attached hack/work-around for vmbuilder was to skip a
sector when building the first partition.

** Changed in: parted (Ubuntu)
       Status: Incomplete => Confirmed

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https://bugs.launchpad.net/bugs/556167

Title:
  vmbuilder uses parted to create disk images, which leads to broken
  sector counts (cannot use grub2 on disk images created by
  vmbuilder/parted)

Status in “parted” package in Ubuntu:
  Confirmed
Status in “vm-builder” package in Ubuntu:
  Confirmed

Bug description:
  parted uses a fixed sector count of "32" when writing partitions to a
  non-block device.  (See init_file() via linux_new() in
  libparted/arch/linux.c)  As a result, the track size of disks created
  with vmbuilder is 32 sectors, not the generally expected 63 sectors
  (used with LBA mode).  This means that the "embedding region" between
  the end of the MBR and the start of partition 1 is half the "normal"
  size, and grub2 will not install.

  /usr/sbin/grub-setup: warn: Your embedding area is unusually small.
  core.img won't fit in it..

  Fastest solution I see is to use an environment override as already
  done in init_file() for sector size.  Perhaps PARTED_SECTORS?  And
  then set this to 63 when calling parted from vm-builder.

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