[Libguestfs] appliance VM won't start, can't find /init, but /init is in the image.

[Richard W.M. Jones]

On Fri, Aug 12, 2011 at 03:13:30PM -0700, David Konerding wrote:
> febootstrap: mounting /proc
> febootstrap: uptime: 0.40 0.19
> febootstrap: ext2 mini initrd starting up
> febootstrap: mounting /sys
> febootstrap: internal insmod libcrc32c.ko
> insmod: init_module: libcrc32c.ko: Unknown symbol in module
> febootstrap: internal insmod crc32c-intel.ko
> insmod: init_module: crc32c-intel.ko: No such device
> febootstrap: internal insmod crc-itu-t.ko
> febootstrap: internal insmod crc32c.ko
> febootstrap: internal insmod crc-ccitt.ko
> febootstrap: internal insmod crc7.ko
> febootstrap: internal insmod scsi_transport_spi.ko
> febootstrap: internal insmod sym53c8xx.ko
> febootstrap: internal insmod sparse-keymap.ko
> febootstrap: internal insmod ideapad-laptop.ko
> insmod: init_module: ideapad-laptop.ko: No such device
> febootstrap: internal insmod virtio_ring.ko
> febootstrap: internal insmod virtio.ko
> febootstrap: internal insmod virtio-rng.ko
> febootstrap: internal insmod virtio_console.ko
> febootstrap: internal insmod virtio_balloon.ko
> febootstrap: no ext2 root device found

It appears the kernel doesn't include an ext2 driver or module.

The Ubuntu kernel that we use has ext2 compiled in:

CONFIG_EXT2_FS=y

Also the Fedora kernels have direct ext2 support compiled in.

febootstrap *ought* to be able to find the ext2.ko module for your
kernel and load it into the initrd.  According to the output above,
this didn't happen, which would indicate one of:

 - you don't have ext2.ko under the modules path

 - the module should be ext4.ko (because the kernel option
   CONFIG_EXT4_USE_FOR_EXT23=y is enabled) -- this is a bug in
   febootstrap

 - you have the module, but the appliance wasn't rebuilt (did you
   rm -rf {/var,}/tmp/.guestfs-* ?)

 - it's not a well-tested path because everyone else has this compiled
   in, so febootstrap is broken for some other reason

Here is the code:

http://git.annexia.org/?p=febootstrap.git;a=blob;f=helper/ext2initrd.c;h=da4bf48ac9a56f4d111b623fafd3f92dc7cab2cd;hb=HEAD#l50

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
New in Fedora 11: Fedora Windows cross-compiler. Compile Windows
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