Boot Ubuntu 12.04 with grub and /boot partition

Hello,

I'am trying to run Ubuntu 12.04 (32bits) with a root partition encrypted.

I asumed that this is possible within Linode, and I followed https://help.ubuntu.com/community/Encry … OnIntrepid">https://help.ubuntu.com/community/EncryptedFilesystemOnIntrepid

The plan is to boot using grub and mount the root partition then. A passphrase will be asked during the boot to mount the root

As a previous step I set up a box with:

  • separate /boot partition (in /dev/xvda ext3)

  • swap partition (in /dev/xvdb)

  • Ubuntu 12.04 root partition (in /dev/xvdc ext3)

fstab is modified to reflect teh partitions

# <file system=""><mount point=""><type><options><dump><pass>proc        /proc        proc    defaults                       0 0
/dev/xvda   /boot        ext3    defaults                       0 0
/dev/xvdc   /            ext3    noatime,errors=remount-ro      0 1
/dev/xvdb   none         swap    sw                             0 0</pass></dump></options></type></mount></file> 

The system is booting if the profile selected is

Kernel 'Latest 3.4(3.4.2-linodeXX)' ,

root device : Standard /dev/xvdc, i

nitrd – No initrd --

Xenify Distro

The next step is to boot using grub

I followed Linode guide ( http://library.linode.com/linode-platfo … grub-howto">http://library.linode.com/linode-platform/custom-instances/pv-grub-howto ). Even the last update is for 11.04. It should work for 12.04

As the guide suggest, I modified /boot/grub/menu.lst and update-grub

getting at the bottom of the file

title        Ubuntu 12.04 LTS, kernel 3.2.0-26-virtual
root        (hd0)
kernel        /vmlinuz-3.2.0-26-virtual root=/dev/xvda console=hvc0 ro quiet quiet splash 
initrd        /initrd.img-3.2.0-26-virtual

title        Ubuntu 12.04 LTS, kernel 3.2.0-26-virtual (recovery mode)
root        (hd0)
kernel        /vmlinuz-3.2.0-26-virtual root=/dev/xvda console=hvc0 ro quiet  single
initrd        /initrd.img-3.2.0-26-virtual

Then, I created a configuration profile with:

Kernel: pv-grub-x86_32

Block assignements: /dev/xvda –> /boot , /dev/xvdb --> swap and /dev/xvdc --> 12.04 LTS Disk image (what should be my root)

initrd --> --No Initrd--

root device --> standard /dev/xvda (this is the block where my boot is,no?)

Xenify Distro --> NO

Booting with this configuration does not succeed and it gets stuck in the grubdom menu:

Showing last 100 lines from current boot
-----------------------------------------
Xen Minimal OS!
start_info:   0x9e8000
  nr_pages:   131072  shared_inf: beb6b000
  pt_base:    0x9eb000  mod_start:  0x0
  mod_len:    0
  flags:      0x0
  cmd_line:   (hd0)/boot/grub/menu.lst
  stack:      0x947780-0x967780
MM: Init
  _text:        0x0
  _etext:       0x60dec
  _erodata:     0x75000
  _edata:       0x7cb58
  stack start:  0x947780
  _end:         0x967d14
  start_pfn:    9f7
  max_pfn:      20000
Mapping memory range 0xc00000 - 0x20000000
setting 0x0-0x75000 readonly
skipped 0x1000
MM: Initialise page allocator for af1000(af1000)-0(20000000)
MM: done
Demand map pfns at 20001000-a0001000.
Heap resides at a0002000-e0002000.
Initialising timer interface
Initialising console ... done.
gnttab_table mapped at 0x20001000.
Initialising scheduler
Thread "Idle": pointer: 0xa0002008, stack: 0xc00000
Initialising xenbus
Thread "xenstore": pointer: 0xa0002478, stack: 0xc10000
Dummy main: start_info=0x967880
Thread "main": pointer: 0xa00028e8, stack: 0xc20000
"main" "(hd0)/boot/grub/menu.lst" 
vbd 51712 is hd0
******************* BLKFRONT for device/vbd/51712 **********

backend at /local/domain/0/backend/vbd/596/51712
Failed to read /local/domain/0/backend/vbd/596/51712/feature-flush-cache.
409600 sectors of 0 bytes
**************************
vbd 51728 is hd1

    GNU GRUB  version 0.97  (524288K lower / 0K upper memory)

       [ Minimal BASH-like line editing is supported.   For
         the   first   word,  TAB  lists  possible  command
         completions.  Anywhere else TAB lists the possible
         completions of a device/filename. ]

grubdom>       

I guess that there is something bad in my grub configuration.

I tried changing the 'root device' setting in the Linode configuration Profile to /dev/xvdc (where my root lives) but the same result.

I am totally lost, and no other topics / documents in Linode helped me.

Questions

What is happening with my grub based booting?

Is it a problem with Ubuntu, Kernel or Linode version?

Is it possible to boot from a separate /boot partition and mount an encrypted / root partition on Linode?

If so, mm I following the right stepts?

Any help that makes me be on the right track will be really appreciated.

J

2 Replies

What you're trying to do is possible (I've done it) sounds like your boot partition doesn't play well with the linode manager, I expect your /boot partition has no actual folder called "boot" and has everything inside the root of the partition which is fine except the linode manager looks for the menu.lst file in /boot/grub/menu.lst

Try creating a folder in your boot partition called "boot" and then copy your grub folder into that and reboot. I think that's all you need to do it's been a bit since I've done this.

Thanks obs,

that was the problem.

I copied all files within /boot (that is, my sepparate parition /dev/xvda <–> /boot) in /boot/boot

(it seems that linode manager looks for /boot/grub/menu.lst in the partition specified as boot)

In menu.lst I checked that root and boot partitions were properly set > "root(x,y)" refers to the boot partition, while "root=/dev/…" refers to the partition containing the / directory

after update-grub (and copying to /boot/boot/grub/menu.lst) I had

title      Ubuntu 12.04 LTS, kernel 3.2.0-26-virtual
root      (hd0)
kernel      /vmlinuz-3.2.0-26-virtual root=[b]/dev/xvdc[/b] console=hvc0 ro quiet quiet splash
initrd      /initrd.img-3.2.0-26-virtual

title      Ubuntu 12.04 LTS, kernel 3.2.0-26-virtual (recovery mode)
root      (hd0)
kernel      /vmlinuz-3.2.0-26-virtual root=/dev/xvdc console=hvc0 ro quiet  single
initrd      /initrd.img-3.2.0-26-virtual

And in linode manager I select:

  • Kernel: pvgrub-x8632

  • Xenify Distro No

  • root device /dev/xvda

Thanks for pointing me in the right direction

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