dracut fails to build bootable initramfs on fc22

[Alex]

Hi,

>>>> I have a fc22 system that's been working fine and now for some reason
>>>> kernel updates result in an unbootable system. It appears to be
>>>> related to dracut failing to build a proper initramfs image.
>>>>
>>>> I have a default initramfs from 4.0.4-300 that works fine, but using
>>>> dracut to build a new initramfs during a kernel update or building it
>>>> manually fails. Rebooting the system only makes it to "Reached target
>>>> Basic System" where it just stops.
>>>>
>>>> I really have no idea how to proceed, so I'd really appreciate any
>>>> ideas for troubleshooting this further.
>>>
>>> In the GRUB menu, press e to edit the default boot entry. Find the
>>> linux16 or linuxefi line, scroll to the end and remove rhgb quiet. Add
>>> systemd.log_level=debug rd.shell and then either control-x or F10 to
>>> boot. You should get a ton more debugging information, and when
>>> there's a failure you'll get a shell. There you can mount some volume
>>> like a USB stick somewhere like /mnt or if that doesn't exist then use
>>> /sysroot
>>
>> I'm at the point where I have a dracut shell and have inserted a USB
>> stick formatted with ext2. The device is detected, but apparently no
>> device has been assigned to it.
>>
>> Looking in /dev, only my hard disks are there among the block devices.
>>
>
> I believe USB drives show up as /dev/sda*
>
> mkdir /mnt/myusbdrive
> mount /dev/sda1 /mnt/myusbdrive

Yes, the problem is there is no device name associated with the USB
stick. There are /dev/sd[a-e] for the hard disks, but for some reason
none for the USB stick. That is the problem I am having.

>> Any idea how to mount a USB stick in dracut? Interestingly, I can't
>> find anything about this problem with Google.
>>
>
> Not sure if dracut has mount, but If you got to dracut than you should have been prompted for boot options, one if which is rescue mode (even if you did not you can use the install media to run in rescue mode). I suggest booting in that, which should give you an option to search for and load your system partition, and drop you into a suitable rescue mode in which you could issue the following commands:
>
> more /etc/fstab
> blkid
> lvdisplay
>
> If your /etc/fstab uses names vs. UUID for partitions I would change those the UUID of the partitions listed in the blkid output and reboot. At least verify that the names are the still the same used in in /etc/fstab
>
> I ran into this problem several times when I upgrading, and it’s recommended to use UUIDs, as names can change.

The reason I need to mount the USB stick is to save the sosreport file
after an unsuccessful boot. Is there any difference in the way devices
are managed in a rescue mode versus just booting a kernel?

Thanks,
Alex