cgpt now supports generating hybrid MBRs and the classic style mbr.bin
from any version of SYSLINUX should work the same with the hybrid MBR.
The other code, gptmbr.bin, changes after SYSLINUX 3. Switching lets me
play with different versions of SYSLINUX without breaking everything.
With this change all images feature a hybrid MBR so the special case for
some VM platforms has been removed.
The funky UUID and other special settings should only be applied to
coreos-rootfs and coreos-usr partitions which will never be fscked. When
STATE becomes ROOT in -usr images it gets fsked while mounted read-only
and fsck updates the filesystem's UUID if it is blank. Turns out this
causes disagreement between the kernel and the disk leading to bad
things. A related issue was fixed in a newer version of tune2fs but
unless I missed it the same bugfix didn't make it into e2fsck so
updating wouldn't resolve the issue.
http://e2fsprogs.sourceforge.net/e2fsprogs-release.html#1.42.9
Now disk_util is aware of the weird ext2 read-only hack, both by
providing a command to manipulate it and support in the mount command to
automatically set the 'ro' mount option for filesystems with it.
Making mount aware of the hack makes it much easier to mount prod
images with a mix read-only and read-write filesystems.
write_gpt --update <img> will read an existing image and make sure all
existing partitions will not get moved or truncated in the new layout.
This is mostly useful for resizing the final partition or just rewriting
metadata like partition types and labels.
Merge GetPartitionTable and partition alignment from WritePartitionTable
into LoadPartitionConfig so that all this config manipulation code is in
one place and inheritance from the 'base' layout is more predictable.
This isn't a feature we've been using as far as I know and if someone
needs a custom partition layout it's probably better to just add it to
the json file. Removing this avoids some complexity.
Move from optparse to argparse. Move layout file and layout type to
global options with reasonable default values so every command doesn't
need to them. Adjust calling scripts to match.
For now layout type is being passed via an environment variable
DISK_LAYOUT_TYPE but this is a temporary situation.
