mounting .iso-file using grub command(s)

Rosika · 04-09-2019, 10:33 AM

Hi,

does anyone know whether it´s possible to mount an .iso-file which is located in my /home-partition, directly from grub2?
But not using the method of creating a menuentry in /etc/grub.d/40_custom . I´ve found some documentation referring to that.

What I´m looking for is a command sequence that I can enter in the grub-shell.

Thanks a lot in advance.

Greetings.
Rosika

yancek · 04-09-2019, 01:23 PM

THe link below is to the Grub2 manual and as you can see under the list of commands available, mount is not one of them. If you want to know if you can boot an iso directly from the Grub menu, the answer is yes. See the 2nd link below.

https://www.gnu.org/software/grub/manual/grub/grub.html

https://www.howtogeek.com/196933/how...ur-hard-drive/

Rosika · 04-10-2019, 07:24 AM

Hi yancek,

thanks for your answer.
So basically I have to create a menuentry in /etc/grub.d/40_custom. That´s what I wanted to know.
It´s a bit of a shame though, as I have to edit the respective file each time I want to swap ISOs.
Never mind.

One additional question:

Grub2, when using the command line, gives me

Code:

ls : /hd0) (hd0,msdos3) (hd0,msdos2) (hd0,msdos1) (hd1) (hd2) (hd2,msdos1) (fd0)

as available partitions.
So in /etc/grub.d/40_custom instead of

Code:

loopback loop (hd0,2)$isofile

I´d have to type

Code:

loopback loop (hd0,msdos2)$isofile

, right?

Gretings
Rosika

Rosika · 04-10-2019, 11:54 AM

Hi,

I tried it out and in fact you can boot into an .iso directly from grub by typing in commands. In my case:

Code:

 > set isofile="/home/rosika/Desktop/Dokumente/prov_bionic/zu_xubuntu/xubuntu-18.04.2-desktop-i386.iso"
 > loopback loop (hd0,msdos2)$isofile
 > linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=$isofile noprompt noeject 
 > initrd (loop)/casper/initrd  
 > boot

The final "boot"-command triggers it off.

The thus mounted xubuntu worked well. I tried it out as a live-system.

Yet when shutting it down I noticed in the shutdown-logs that there were 2 "failed"-messages. I believe they referred to
unmounting of something. Yet the shutdown proceeded without any difficulties.

When powering up my installed Lubuntu afterwards however I got a "Started file system check" message. And the check was done accordingly. After that my system booted normally.

My question is: Am I right in assuming that the two described phenomena are correlated?

Cheers
Rosika

yancek · 04-10-2019, 02:07 PM

Quote:

So basically I have to create a menuentry in /etc/grub.d/40_custom.

No. It depends upon what you want to do. If you want to boot and use the iso multiple times, that is the best method. If you want to boot it once for the prupose of installing it to a hard drive, better to just put the entry in grub.cfg. If you do this, don't update grub as it will remove the entry.

Yes, you can as you found just enter the complete menuentry on boot as you did. Just a lot of typing. As far as the error messages you got, I"m not sure without knowing the exact message.

Rosika · 04-11-2019, 06:17 AM

Thanks yancek for your reply.

Quote:

Yes, you can as you found just enter the complete menuentry on boot as you did. Just a lot of typing

Yes, you´re right. I found that out the hard way, too.

Quote:

If you want to boot it once for the prupose of installing it to a hard drive, better to just put the entry in grub.cfg. If you do this, don't update grub as it will remove the entry.

That´s a very useful info. Thanks a lot.

Yet after trying out mounting a xubuntu-iso from grub yesterday I´m expriencing another problem with my main system:

Just to clarify: My physical system is Lubuntu.

When I now run

Code:

sudo iftop -i wlxe4beed63ad6d

my ip-address is displayed correctly with DNS resolution off. But with DNS resolution on I get xubuntu as displayed name!!!!!!!

That´s only after yesterday´s experiment with mounting the xubuntu-iso from grub.

So do you have any ideas what could be amiss here?

Greetings.
Rosika

yancek · 04-11-2019, 07:01 AM

Quote:

So do you have any ideas what could be amiss here?

Not really. You turn DNS resolution off how, on Lubuntu? And run the command from Lubuntu/Xubuntu?

Rosika · 04-11-2019, 07:22 AM

Hi,

Quote:

You turn DNS resolution off how, on Lubuntu? And run the command from Lubuntu/Xubuntu?

I´m running the iftop-command from my Lubuntu main system. I can toggle resolution on/off by hitting the "n"-key.

Curious thing though:

I have two profiles for my WLAN-connection. One is with DHCP automatically, the other is a profile
with which I assign a defined ip-address.
But only using the first one gives me "xubuntu". The latter one gives me "rosika@rosika-Lenovo-H520e", as it used to be.
(And indeed, I used the first one with the xubuntu-iso.)

All of this leads me to believe that the issue is with the router......

Greetings.
Rosika