REAR Backup Rescue and FOG Project

[matekub]

Hello,

I want add REAR Rescue boot ISO to FOG PXE.

I’ve copied all files (initrd.cgz and kernel) to TFTP root folder and it is visible on server.

I’ve added new entry to PXE by using GUI: Parameters are:

kernel tftp://${fog-ip}/kernel
initrd tftp://${fog-ip}/initrd.cgz
imgargs initrd=initrd.cgz root=/dev/ram0
boot || goto MENU

Clients are able to connect to PXE server, download kernel, download initrd.cgz and then start kernel: then I was facing the issue - Kernel panic - not syncing: VFS: Unable to mount root fs on unknow-block(0,0)

Something is wrong with my settings or names? This is my first time with FOG.

[george1421]

The unable to mount root fs means the kernel is having an issue connecting to the virtual hard drive (initrd). Your settings look right as long as “kernel” is matched to the initrd.cgz file it should boot. The only thing I can think is there are additional kernel parameters (imgargs) that might be required.

So on that rescue cd is the boot loader based on grub or syslinux? Is there a grub.cfg, syslinux.cfg, or isolinux.cfg file? Is there a pxelinux directory on the ISO? These might contain additional kernel parameters needed to boot the kernel.

[matekub]

Thanks for your help. Really appreciate.

I’d like to add this backup boot media to Fog: https://relax-and-recover.org/

When I build REAR Backup Rescue I can select as output PXE and ISO build:

1. PXE
   Then I have:
   kernel and initrd.cgz file + config file:

default hd
prompt 1
timeout 300

label hd
    localboot -1
    say ENTER - boot local hard disk
    say --------------------------------------------------------------------------------
    display /localhost.message
    say ----------------------------------------------------------
    say rear = disaster recover this system with Relax-and-Recover
label rear
    kernel /localhost.kernel
    append initrd=/localhost.initrd.cgz root=/dev/ram0 vga=normal rw  selinux=0 

2. ISO
   Then I have this content in ISO:
   EFI G:\EFI
   boot G:\boot
   isolinux G:\isolinux
   BOOT G:\EFI\BOOT
   fonts G:\EFI\BOOT\fonts
   locale G:\EFI\BOOT\locale
   BOOTX64.efi G:\EFI\BOOT\BOOTX64.efi
   embedded_grub.cfg G:\EFI\BOOT\embedded_grub.cfg
   grub.cfg G:\EFI\BOOT\grub.cfg
   grubx64.efi G:\EFI\BOOT\grubx64.efi
   grub G:\boot\grub
   efiboot.img G:\boot\efiboot.img
   grub.cfg G:\boot\grub\grub.cfg
   boot.cat G:\isolinux\boot.cat
   chain.c32 G:\isolinux\chain.c32
   hdt.c32 G:\isolinux\hdt.c32
   initrd.cgz G:\isolinux\initrd.cgz
   isolinux.bin G:\isolinux\isolinux.bin
   isolinux.cfg G:\isolinux\isolinux.cfg
   kernel G:\isolinux\kernel
   ldlinux.c32 G:\isolinux\ldlinux.c32
   libcom32.c32 G:\isolinux\libcom32.c32
   libgpl.c32 G:\isolinux\libgpl.c32
   libmenu.c32 G:\isolinux\libmenu.c32
   libutil.c32 G:\isolinux\libutil.c32
   menu.c32 G:\isolinux\menu.c32
   message G:\isolinux\message
   pci.ids G:\isolinux\pci.ids
   rear.help G:\isolinux\rear.help
   reboot.c32 G:\isolinux\reboot.c32
   vesamenu.c32 G:\isolinux\vesamenu.c32

[george1421]

@matekub said in REAR Backup Rescue and FOG Project:

I see you were missing a few kernel arguments, but that shouldn’t have had an impact on the kernel mounting the filesystem.

kernel tftp://${fog-ip}/kernel
initrd tftp://${fog-ip}/initrd.cgz
imgargs initrd=initrd.cgz root=/dev/ram0 vga=normal rw selinux=0
boot || goto MENU

You got the kernel and initrd.cgz from the isolinux directory off the ISO?

[matekub]

No, I have kernel and initrd from PXE option in REAR - then it doesn’t create ISO, only files with kernel and initrd + above config for “PXE Server”.

[george1421]

@matekub You posted the config file exactly as it was presented to you?

what confuses me is this reference to the kernel

kernel /localhost.kernel

for pxe booting that localhost.kernel should be the kernel name exactly localhost.kernel not what you supplied as kernel

[matekub]

sorry, I’ve changed filename in meantime

[matekub]

I guess this may be the issue - https://github.com/rear/rear/issues/2359
I’ve also probably have files for BIOS, not UEFI.

But how to add entry in FOG that can be handled by GRUB like in above issue?

This is a workaround mentioned in that topic:

Workaround:
i have create the file grub.cfg and calling the kernel and initrd.cgz files
[root@PXE-BOOT /]# cat /var/lib/tftpboot/efi.x64/grub.cfg
set menu_color_normal=white/black
set menu_color_highlight=black/light-gray
set timeout=30
insmod png

Menu Start

menuentry ‘Boot from Local Drive’ {
exit
}
menuentry ‘Rear Recover for node4’ {
linuxefi /node4.kernel
initrdefi /node4.initrd.cgz
}
menuentry ‘Rear Recover for node5’ {
linuxefi /node5.kernel
initrdefi /node5.initrd.cgz
}

Because I’ve generated this and trying those settings in FOG:
Recover mkbackup created the file rear-node4 suitable for BIOS not UEFI
[root@PXE-BOOT node4]# cat rear-node4
default hd
prompt 1
timeout 300

label hd
localboot -1
say ENTER - boot local hard disk
say --------------------------------------------------------------------------------
display /node4.message
say ----------------------------------------------------------
say rear = disaster recover this system with Relax-and-Recover
label rear
kernel /node4.kernel
append initrd=/node4.initrd.cgz root=/dev/ram0 vga=normal rw selinux=0 console=ttyS0,9600 console=tty0

[george1421]

@matekub said in REAR Backup Rescue and FOG Project:

kernel /node4.kernel
append initrd=/node4.initrd.cgz root=/dev/ram0 vga=normal rw selinux=0 console=ttyS0,9600 console=tty0

converting syslinux commands over to iPXE is not hard because both have a similar lineage. So in iPXE format the command would look like this.

kernel tftp://${fog-ip}/node4.kernel
initrd tftp://${fog-ip}/node4.initrd.cgz
imgargs initrd=node4.initrd.cgz root=/dev/ram0 vga=normal rw selinux=0 console=ttyS0,9600 console=tty0

This would assume that you had a node4.kernel and node4.initrd.cgz in the /tftpboot directory.

The grub menus are similar to syslinux and iPXE. But for grub I don’t see it pass any kernel parameters.

Now there are two variations of the above menu depending how the kernel deals with kernel parameters.

The first one inserts the kernel name just before initrd.

kernel tftp://${fog-ip}/node4.kernel
initrd tftp://${fog-ip}/node4.initrd.cgz
imgargs node4.kernel initrd=node4.initrd.cgz root=/dev/ram0 vga=normal rw selinux=0 console=ttyS0,9600 console=tty0

The second alternate method is by appending the imgargs to the end of the kernel call line and imgargs are not used.

kernel tftp://${fog-ip}/node4.kernel initrd=node4.initrd.cgz root=/dev/ram0 vga=normal rw selinux=0 console=ttyS0,9600 console=tty0
initrd tftp://${fog-ip}/node4.initrd.cgz

Some of this is a bit of black art skills to make it work.

[matekub]

Thanks. Checking it. It was very helpful.

But what about GRUB settings and EFI parameters like this? It was mentioned in that post\issue - that created and used by my files are not for EFI

Then he did this:
linuxefi /node4.kernel
initrdefi /node4.initrd.cgz

Should I add a command like LINUXEFI and INITRDFI?

Sorry I’m quite new in this area

UPDATE: (Checked)
Now, I don’t have KERNEL PANIC - not syncing VFS - Unable to mount root FS on unknown block(0,0).

Now, I’ve got error message before loading kernel:

EFI Stub: Error: Failed to alloc highmem for files
Trying to load files to higher address

Both options (1,2) cause the same error.

[george1421]

@matekub said in REAR Backup Rescue and FOG Project:

Then he did this:
linuxefi /node4.kernel
initrdefi /node4.initrd.cgz
Should I add a command like LINUXEFI and INITRDFI?

These are grub specific commands. They tell grub to uefi boot these kernels. Adding them to iPXE will cause ipxe to error with unknown command.

EFI Stub: Error: Failed to alloc highmem for files
Trying to load files to higher address

It almost sounds like you are trying to boot a bios kernel on a uefi system or the other way around. Did option 3 just error out?

[matekub]

Thanks for your time and response.

Yes, any of those 3 commands didn’t work.

Based on information from that topic in REAR GitHub - the user after using PXE mode, they had pxelinux config and probably as you mentioned kernel (kernel file) and maybe file system (initrg.cgz) for BIOS, not UEFI.
I guess i have the same and trying to boot on UEFI system.

How to determine which file is for UEFI? I guess it should be part of ISO which works fine on BIOS and UEFI system.

I have this content of ISO:

Then I have this content in ISO:
EFI G:\EFI
boot G:\boot
isolinux G:\isolinux
BOOT G:\EFI\BOOT
fonts G:\EFI\BOOT\fonts
locale G:\EFI\BOOT\locale
BOOTX64.efi G:\EFI\BOOT\BOOTX64.efi
embedded_grub.cfg G:\EFI\BOOT\embedded_grub.cfg
grub.cfg G:\EFI\BOOT\grub.cfg
grubx64.efi G:\EFI\BOOT\grubx64.efi
grub G:\boot\grub
efiboot.img G:\boot\efiboot.img
grub.cfg G:\boot\grub\grub.cfg
boot.cat G:\isolinux\boot.cat
chain.c32 G:\isolinux\chain.c32
hdt.c32 G:\isolinux\hdt.c32
initrd.cgz G:\isolinux\initrd.cgz
isolinux.bin G:\isolinux\isolinux.bin
isolinux.cfg G:\isolinux\isolinux.cfg
kernel G:\isolinux\kernel
ldlinux.c32 G:\isolinux\ldlinux.c32
libcom32.c32 G:\isolinux\libcom32.c32
libgpl.c32 G:\isolinux\libgpl.c32
libmenu.c32 G:\isolinux\libmenu.c32
libutil.c32 G:\isolinux\libutil.c32
menu.c32 G:\isolinux\menu.c32
message G:\isolinux\message
pci.ids G:\isolinux\pci.ids
rear.help G:\isolinux\rear.help
reboot.c32 G:\isolinux\reboot.c32
vesamenu.c32 G:\isolinux\vesamenu.c32