Previously fsck output was suppressed to reduce the amount of noise in
build logs on the assumption that fsck really shouldn't have a reason to
fail. The filesystem is freshly created after all. However some users
have reported that fsck is failing but without error messages we don't
know why.
This change changes the default 'bytes-per-inode' ration from 16K to 4K,
the block size. To prevent this from wasting too much space change the
inode size from the default 256 to the minimum size, 128. Larger inodes
are used to store extended attributes more efficiently but since we do
not use SELinux the majority of files do not have security attributes.
These defaults may be modified via the new `bytes_per_inode` and
`inode_size` options.
Mark the initial copy of CoreOS as 'successful' and with a non-zero
priority. Required to boot with a stricter interpretation of the
partition selection scheme which ignores partitions that have a priority
of zero. The new grub implementation follows this rule and is what the
original ChromeOS spec used too.
For the sake of completeness if multiple partitions are configured in
the json file with this feature they will be prioritized in disk-order.
So far the default iteration order of python dicts has mostly matched
the order that we want the partitions on disk but this is not always the
case. I caught the BIOS-BOOT partition being ordered on disk after the
USR-A partition. Nothing bad came of this but consistancy is good.
The VHD disk format internally includes CHS addressing and qemu-img
respectfully aligns disk images to the common 16 heads 63 sectors
geometry when possible. This is unfortunate since images uploaded to
Azure must also be aligned to 1MB we normally do.
Since qemu-img doesn't have a way to handle this well right now adjust
our existing alignment logic to create disk images aligned to both.
We don't need to do anything like manually install the MBR boot code
for grub but we do need to continue to expose the ESP partition as a
hybrid partition to support pvgrub.
Calling cgpt create when resizing zeros the MBR boot code. This worked
with the syslinux setup because the boot code was re-written. When not
using syslinux it is easier to just preserve the existing MBR instead.
Attempting to work around an apparent race in mtools, the command
'extlinux' these days is just the install tool for mounted partitions
while 'syslinux' is for unmounted devices.
The new Update() performs the same tasks as the old Resize()
in addition to formatting previously-unformatted partitions. This
allows children disk-layouts to repartition the base layout in
addition to resizing.
btrfs isn't designed for small volumes and can run out of space sooner
than one would expect in our current setup, particularly with docker.
To try to improve the situation always create the filesystem initially
as 2GB instead of 512MB using the default settings: metadata is
duplicated, data is single, not mixed. The mixed setting may have been
partly why our performance can be so poor. For the default vm layout
use 6GB instead of 3GB, about what we use for EC2.
Using the classic mbr.bin was only needed during the transition from
syslinux 3 to 6 because the behavior of gptmbr.bin changed after 3.
Now that the transition is done and cgpt supports the new scheme now it
is time we switched back. This avoids depending on using a hybrid MBR.
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.
