Dual Boot OS w/ .iso file

ondoho · 03-11-2016, 12:54 AM

Quote:

Originally Posted by yancek

If you are booting an iso, you just point to it in grub.cfg with Grub2. I usually put it in the / of the filesystem I am booting from but it can also be in the /boot directory and possibly elsewhere. I haven't tried anything else.

The menuentry below is an example of an entry in the Grub2 grub.cfg file to directly boot the Ubuntu 14.04 iso. It's in the / of the sdb3 partition so that would have to be changed.

i will try this now.
already added the entry to /boot/grub/grub.cfg, will reboot soon.

yancek · 03-11-2016, 08:53 AM

Quote:

In this case the derivative is Black Lab Linux that I can easily transfer to my Centos box from my Slack box with a pendrive.
What configuration file does the .iso of Black Lab Linux go in?

I don't know if Black Lab will work but you can certainly try it. I've never used it.

Quote:

I would like to try to boot other distributions as a practice but don't understand how to 'loop mount the iso

It's like any mount. First create the mount point and then run the mount command. If you have the Black Lab iso in your /home/user/Downloads directory, create the mount point there and the loop mount command I use is: mount -o loop blacklab.iso blacklab. You would need to run the command from the Downloads directory as root and have created the blacklab directory. The entry below is loop mount of Peppermint Linux in the previously created test directory.

Code:

mount -o loop Peppermint-5-20140623-i386.iso test/

Running ls on the test directory produces the output below which are the standard directories/files shown on an Ubuntu derivative iso files.

Quote:

ls test/
boot/ casper/ dists/ install/ isolinux/ md5sum.txt preseed/ README.diskdefines

Quote:

The ISO file may be stored on any partition accessible to GRUB 2. The partition format does not need to be ext3/4.

I booted the Peppermint iso from an ntfs partition out of curiosity when asked in a post here by another member and it booted. I wouldn't suggest doing that. If you look at the Ubuntu site discussing this (link posted above) I beleive they usually put the iso in the /boot directory. Personally, I always put it in the / of the directory as I've found this to work better. So on your CentOS, either put the iso file in the / or boot directory.

If you don't have a partition on which to install Black Box, create that and format it.

Quote:

Ensuring to properly identify the location of the ISO in the menuentry's PATH is what I'm having trouble with.

If you look at the example menuentry in post #9 above, you will see "set root='hd1,msdos3'" which tells you the iso I am booting is on sdb3, Grub2 counts hard drives from zero, partitions from one. The loopback loop line repeats the drive/partition entry and points to where the iso is which is the / of sdb3. If you put your Black Box iso in the /boot directory you would need to obviously change the entry to:

Quote:

loopback loop (hd1,msdos3)/boot/ubuntu-14.04.2-desktop-i386.iso

I would copy and paste the entry from post 9 above and then modify it to fit your situation. If you don't put a space where one should be or do put a space where one should not be, it won't boot and the error message won't help much. This would be in the CentOS /boot/grub or grub2 directory where your grub.cfg file is.

Quote:

Once I figure that out the partition will be mounted by Grub2; right?

Not sure what you mean by that. What partition? The iso should be on the partition you are booting from, CentOS. If you create a partition on which to install Black Box, you need to point to it during the install.

A final not, despite the message at the top of the grub.cfg file, simply putting a new entry in it manually does not create a problem as long as you do not run grub-mkconfig. Since you only need to boot once, not much point in making it permanent.

Ztcoracat · 03-14-2016, 04:17 PM

Thank you yancek but I don't fully understand. This is new to me.

I'm looking at this thread in order to create a mount point.
http://www.linuxquestions.org/questi...-linux-906731/

Ztcoracat · 03-14-2016, 06:10 PM

Is this correct?

Code:

sudo mount -0 loop /home/zebracat/Downloads/black-lab-702-x86_64.iso /mnt/iso

yancek · 03-14-2016, 09:26 PM

Quote:

Is this correct?

Yes. After running the command you can check by simply navigating to the /mnt/iso directory where you should see the directories/files on the iso. The only reason you need to loop mount is to get the menuentry from isolinux to convert to your grub.cfg file. If Black Lab is an Ubuntu derivative, it should show directories/files similar to what I posted in my last post. If there is a /boot directory, take a look in it and see if there is a Grub directory. Some of the distributions will have a loopback entry. If there isn't one, check to see if there is a grub.cfg file. Otherwise, you will need to go to the isolinux directory and find the menu. It could be isolinux.cfg, text cfg or some other file. It will show a standard menuentry/label. The basic process of converting it to a Grub entry is to take all the boot parameters you see in isolinux on the initrd line and put them on the linux line for the entry in grub.cfg in CentOS.

Modify your set root and loopback loop lines to point to the correct drive/partition and path to the iso shown in the example menuentry I posted earlier. In your post above: /home/zebracat/Downloads/black-lab-702-x86_64.iso

I've never used Black Lab so I don't know if it will boot from the iso. Most Linux distributions won't, most major Ubuntus will. I have never tried to boot from a user Downloads file so I don't know if it will work. I usually have the iso in the / directory or the boot directory. Good luck and post back with the results or questions.

Almost forgot, after you put the entry in the CentOS grub.cfg file do NOT run grub-mkconfig.

Ztcoracat · 03-15-2016, 04:57 PM

Ok so when I run:

Code:

su mount -0 loop /home/linuxcat/Downloads/black-lab-702-x86_64.iso /mnt/iso

That will mnt the fs to the mnt point?

Than I'll make the Menu Entry and update Grub.
Now when I make the Menu Entry I was only able to find a 'grub.d' file.
Is that the right file?

Does the Menu Entry have to be done first before running the mnt cmd?

yancek · 03-15-2016, 05:42 PM

Quote:

That will mnt the fs to the mnt point?

Yes. cd to /mnt/iso and you should see he directories/files from the iso.

Quote:

Does the Menu Entry have to be done first before running the mnt cmd?

No, in fact you won't know what to use for a menuentry until you loop mount and take a look in isolinux or syslinux. I don't know what Black Lab uses to boot. As I indicated in my last post, the only reason to loop mount the iso is to get the info you need for the menuentry. Usually this will be in a file isolinux.cfg, syslinux.cfg and sometimes a txt.cfg file. Once you find that, you copy it to the /boot/grub/grub.cfg file on CentOS Once you have done that, you save the changes in grub.cfg and reboot.

Quote:

Than I'll make the Menu Entry and update Grub.

There is no need to update grub if you put the menuentry in grub.cfg. In fact if you put it there and update-grub it will be gone. If you want you could instead put the entry in the 40_custom file in /etc/grub.d and then run update-grub.

When you go to the /mnt/iso directory after mounting, you should have a casper directory and it should contain the vmlinuz and initrd files. If they are there, just copy the Ubuntu entry I posted above and modify the iso name using the blacklab iso name and point to the correct drive/partition where the iso file is, your user Downloads file. If you don't have casper, you will have to change the entry. If you want do an ls on the /mnt/iso after the loop mount and post it.

Ztcoracat · 03-15-2016, 11:42 PM

Quote:

Usually this will be in a file isolinux.cfg, syslinux.cfg and sometimes a txt.cfg file. Once you find that, you copy it to the /boot/grub/grub.cfg file on CentOS Once you have done that, you save the changes in grub.cfg and reboot.

I'll work on that tomorrow evening and let you know how it goes.

Ztcoracat · 03-16-2016, 09:28 PM

Not sure what went wrong?

Code:

[root@localhost linuxcat]# mkdir /media/iso
[root@localhost linuxcat]# mount -0loop /home/linuxcat/Downloads/black-lab-702-x86_64.iso /mnt/iso
mount: invalid option -- '0'

Usage:
 mount [-lhV]
 mount -a [options]
 mount [options] [--source] <source> | [--target] <directory>
 mount [options] <source> <directory>
 mount <operation> <mountpoint> [<target>]

Options:
 -a, --all               mount all filesystems mentioned in fstab
 -c, --no-canonicalize   don't canonicalize paths
 -f, --fake              dry run; skip the mount(2) syscall
 -F, --fork              fork off for each device (use with -a)
 -T, --fstab <path>      alternative file to /etc/fstab
 -h, --help              display this help text and exit
 -i, --internal-only     don't call the mount.<type> helpers
 -l, --show-labels       lists all mounts with LABELs
 -n, --no-mtab           don't write to /etc/mtab
 -o, --options <list>    comma-separated list of mount options
 -O, --test-opts <list>  limit the set of filesystems (use with -a)
 -r, --read-only         mount the filesystem read-only (same as -o ro)
 -t, --types <list>      limit the set of filesystem types
     --source <src>      explicitly specifies source (path, label, uuid)
     --target <target>   explicitly specifies mountpoint
 -v, --verbose           say what is being done
 -V, --version           display version information and exit
 -w, --rw, --read-write  mount the filesystem read-write (default)

 -h, --help     display this help and exit
 -V, --version  output version information and exit

Source:
 -L, --label <label>     synonym for LABEL=<label>
 -U, --uuid <uuid>       synonym for UUID=<uuid>
 LABEL=<label>           specifies device by filesystem label
 UUID=<uuid>             specifies device by filesystem UUID
 PARTLABEL=<label>       specifies device by partition label
 PARTUUID=<uuid>         specifies device by partition UUID
 <device>                specifies device by path
 <directory>             mountpoint for bind mounts (see --bind/rbind)
 <file>                  regular file for loopdev setup

Operations:
 -B, --bind              mount a subtree somewhere else (same as -o bind)
 -M, --move              move a subtree to some other place
 -R, --rbind             mount a subtree and all submounts somewhere else
 --make-shared           mark a subtree as shared
 --make-slave            mark a subtree as slave
 --make-private          mark a subtree as private
 --make-unbindable       mark a subtree as unbindable
 --make-rshared          recursively mark a whole subtree as shared
 --make-rslave           recursively mark a whole subtree as slave
 --make-rprivate         recursively mark a whole subtree as private
 --make-runbindable      recursively mark a whole subtree as unbindable

For more details see mount(8).

I'm running as root and can't view the Grub2 file.
I'm thinking I need to use Vi?

Quote:

[root@localhost linuxcat]# cd /boot/grub2
[root@localhost grub2]# ls
device.map fonts grub.cfg grubenv i386-pc locale themes

yancek · 03-17-2016, 02:59 PM

Quote:

Not sure what went wrong?

The command you entered is incorrect. You need a space after the O and before the loop.

Quote:

I'm running as root and can't view the Grub2 file.

Uhh, what grub2 file? There is no grub2 file. grub2 is a directory and the file you need to edit is grub.cfg. So if you want to use vi then as root user: vi /boot/grub2.grub.cfg

I downloaded Black Lab the other night and booted it from Ubuntu 14.04 which I had installed. The entry below booted Black Lab successfully:

Quote:

menuentry "black lab" {
insmod part_msdos
insmod ext2
set root='hd1,msdos3'
loopback loop (hd1,msdos3)/black-lab-702-x86_64.iso
linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=/black-lab-702-x86_64.iso
initrd (loop)/casper/initrd.gz
}

The iso in the above example is in the / of sdb3. The first time I tried, it failed. It was necessary to install the lupin-casper software in Ubuntu. After doing that, I was able to use the above entry to boot black lab. I also tried booting it from the Downloads directory. That failed. I then moved the iso to the /boot directory. That was successful.

I think you might have problems booting from CentOS. I've tried doing this on Fedora with no success in the past. There was only one option that worked without lupin-casper installed and that was loop mounting the iso and copying the directories/files from the iso to the / of the partition and putting a proper entry in grub.cfg shown below. The directories/files in the / of the iso are these:

casper install isolinux md5sum.txt preseed README.diskdefines ubuntu

It's not likely you have any of these directories/files in the / of CentOS so that should not be a problem. If you do an online search for booting an iso from Grub2, almost all of them are Ubuntu related. From what I've read and tried, I doubt it will work booting from CentOS. As I indicate above, it didn't work with the default Ubuntu and I had to install lupin-casper to get it to boot.

Quote:

menuentry "Blacklab" {
insmod part_msdos
insmod ext2
set root='hd1,msdos3'
linux /casper/vmlinuz boot=casper file=/cdrom/preseed/custom.seed quiet splash --
initrd /casper/initrd.gz
}

Quote:

lupin-casper provides hooks to find an ISO image on a hard disk and to read a preseed file from a hard disk, which are used in the early part

You probably need software similar to lupin-casper which I don't if Red Hat/CentOS/Fedora have. So copying all the files directories/files from the iso to the root of CentOS and adding the menuentry above should work.

You might try booting the iso to see the results. I don't have CentOS so can't test it and I'm not aware of software comparable to lupin-casper for CentOS. Good luck.

Ztcoracat · 03-17-2016, 04:58 PM

I've discovered a problem when trying to access the grub.cfg file.

Code:

The link grub2cfg is broken
This link cannot be used because it's target
:./boot/grub2/grub.cfg" doesn't exist

yancek · 03-17-2016, 06:29 PM

You're using CentOS 7, correct? That release of CentOS uses Grub2 so you must have grub.cfg file somewhere or it wouldn't boot. You see that the link is pointing to 'grub.cfg'. I don't know why it has a grub2.cfg link, never seen that before but I've never used CentOS so...? Take a look in the /boot directory. Do you have a grub directory as well as a grub2 directory.

Are you using UEFI? Might find grub.cfg here: /boot/efi/EFI/fedora/grub.cfg Of course, it wouldn't be fedora, probably centos. I don't use EFI so I have no idea if that matters. Try running the find command:

Quote:

find /boot -name grub.cfg

According to the link below, grub.cfg should be at: /boot/grub2/grub.cfg

http://superuser.com/questions/78130...le-in-centos-7

You could put the menuentry in the /etc/grub.d/40_custom file, save it and run grub-mkconfig and you should then see the black lab entry when you boot.

I removed lupin-casper from Ubuntu and tried booting the iso directly from the /boot directory and this time it booted. Might have had an incorrect menuentry. I would definitely put the iso in the /boot directory.

Ztcoracat · 03-17-2016, 06:55 PM

The boot directory contains 2 grub files. One marked 'grub' that contains a file marked splash .xpm.gz.
The 'grub2' directory has an X on the front of it and it's complaining that I don't have permission to view it.
I ran ls /boot/grub2 and the grub.cfg file is in that directory. I tried using nano to view it and upon doing so the file is empty.

Agreed if it didn't exist it wouldn't boot. I found the boot files but there are too many to list.

Code:

/boot/grub2/i386-pc/part_acorn.mod
/boot/grub2/i386-pc/part_amiga.mod
/boot/grub2/i386-pc/part_apple.mod
/boot/grub2/i386-pc/part_bsd.mod
/boot/grub2/i386-pc/part_dfly.mod
/boot/grub2/i386-pc/part_dvh.mod
/boot/grub2/i386-pc/part_gpt.mod
/boot/grub2/i386-pc/part_msdos.mod
/boot/grub2/i386-pc/part_plan.mod
/boot/grub2/i386-pc/part_sun.mod
/boot/grub2/i386-pc/part_sunpc.mod
/boot/grub2/i386-pc/parttool.mod

When running the find cmd for grub.cfg the terminal as root returns:

Code:

find grub.cfg no such file or directory

No, this is not a UEFI machine and I haven't used UEFI in any way.

yancek · 03-17-2016, 07:26 PM

Quote:

The 'grub2' directory has an X on the front of it and it's complaining that I don't have permission to view it.

Obviously, run as root? Strange that the file is not found with the find command when it is obviously there. You could copy the entry below to the 40_custom files in /etc/grub.d, save it and run the grub-mkconfig command to update grub. Then reboot to see if it shows on your boot menu and boots.

Quote:

menuentry "black lab" {
insmod part_msdos
insmod ext2
set root='hd1,msdos3'
loopback loop (hd1,msdos3)/black-lab-702-x86_64.iso
linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=/black-lab-702-x86_64.iso
initrd (loop)/casper/initrd.gz
}

You would need to change the set root line to the correct partition and put the exact name of the iso. If that doesn't work, you should be able to loop mount black lab and then copy the directories/files from that mount point to the / of your CentOS directory and boot it. I tried this and it booted with no problem.

Quote:

menuentry "Blacklab" {
insmod part_msdos
insmod ext2
set root='hd1,msdos3'
linux /casper/vmlinuz boot=casper file=/cdrom/preseed/custom.seed quiet splash --
initrd /casper/initrd.gz
}

Ztcoracat · 03-17-2016, 07:59 PM

I was finally able to view the grub.cfg file-

Code:

menuentry 'CentOS Linux, with Linux 0-rescue-84da9de2297e494a9a67e135e79bf1fc' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-0-rescue-84da9de2297e494a9a67e135e79bf1fc-advanced-4f9c4f4e-fe63-4c0e-87cc-e17dea438df4' {
	load_video
	insmod gzio
	insmod part_msdos
	insmod xfs
	set root='hd0,msdos1'
	if [ x$feature_platform_search_hint = xy ]; then
	  search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos1 --hint-efi=hd0,msdos1 --hint-baremetal=ahci0,msdos1 --hint='hd0,msdos1'  41d972b5-1780-4093-8d06-36cc0dd63503
	else
	  search --no-floppy --fs-uuid --set=root 41d972b5-1780-4093-8d06-36cc0dd63503
	fi
	linux16 /vmlinuz-0-rescue-84da9de2297e494a9a67e135e79bf1fc root=UUID=4f9c4f4e-fe63-4c0e-87cc-e17dea438df4 ro rd.lvm.lv=cl/root vconsole.font=latarcyrheb-sun16 crashkernel=auto  vconsole.keymap=us rd.lvm.lv=cl/swap rhgb quiet
	initrd16 /initramfs-0-rescue-84da9de2297e494a9a67e135e79bf1fc.img
}

### END /etc/grub.d/10_linux ###

### BEGIN /etc/grub.d/20_linux_xen ###
### END /etc/grub.d/20_linux_xen ###

### BEGIN /etc/grub.d/20_ppc_terminfo ###
### END /etc/grub.d/20_ppc_terminfo ###

### BEGIN /etc/grub.d/30_os-prober ###
### END /etc/grub.d/30_os-prober ###

### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
### END /etc/grub.d/40_custom ###

I have something to tend to bb later.