I am currently struggling with getting pygrub to work. I am using unstable
9327:cf89e8f0831b with 2.6.16-rc6-git3 on CentOS 4 (although the kernel
version should not matter here).
I dedicated the partition /dev/sdb1 to a virtual machine, used fdisk to
sub-partition this into partitions again. Finally I used dmsetup (device
mapper) to temporarily make the partitions available to format and mount
them, and install the guest OS (linux) from a backup archive.
Using a regular xm config, I can happily boot the guest and it works
perfectly (mounts all partitions and just works). I use disk = [
When I use bootloader = "/root/pygrub" instead, I get the following trace
when trying to do xm create:
Traceback (most recent call last):
File "/root/pygrub", line 258, in ?
cf = get_config(file, isconfig)
File "/root/pygrub", line 121, in get_config
fs = fstype.open_fs(fn, offset)
File "/usr/lib/python2.3/site-packages/grub/fsys/ext2/__init__.py", line
35, in open_fs
return Ext2Fs(fn, offset = offset)
ValueError: unable to open file
Error: Boot loader didn't return any data!
I checked the values of fn and offset:
fn = /dev/sdb1
offset = 512
This seems perfectly ok, considering the output of fdisk:
Disk /dev/sdb1: 15.0 GB, 15011103744 bytes
255 heads, 63 sectors/track, 1824 cylinders, total 29318562 sectors
Units = sectors of 1 * 512 = 512 bytes
Device Boot Start End Blocks Id System
/dev/sdb1p1 * 1 208844 104422 83 Linux
/dev/sdb1p2 208845 2313359 1052257+ 82 Linux swap
/dev/sdb1p3 2313360 29302559 13494600 83 Linux
One sector is indeed 512 bytes, so the offset of one sector into /dev/sdb1
seems perfectly ok.
Additionally I tried to copy the partition to an image file with dd. Result:
the same error as above. Now, using lomount gives this error: "vm1.img: File
Copying only the first gigabyte into the image (the boot partition is only
100 mb) makes lomount work (mounts the boot partition correctly), but pygrub
will still say "ValueError: unable to open file" in Ext2Fs, even for the
truncated image file.
Please, help me find and fix this problem.
Michael Paesold | Emerion WebHosting Gmbh
mpaesold gmx at | http://www.emerion.com
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