dracut image with squashfs root filesystem

Message

insane.awmn · Post by **insane.awmn** » Tue Mar 13, 2012 12:04 am

Hello everyone ,
I want to use plymooth so i want to boot my squashfs image with the dracut generated image,i tried some kerne boot l args but with no success .
The dracut ebuild has the module dmsquash-live but i cant find any documentation .

Can anyone help ?

devsk · Post by **devsk** » Thu Aug 16, 2012 4:03 am

Spooky weird. I asked the same question exactly one year before you...ok 1 year and few hours: http://forums.gentoo.org/viewtopic-p-6611051.html

And the spookier part is that nobody knows...

xaviermiller · Post by **xaviermiller** » Thu Aug 16, 2012 6:54 am

Hello,

Take a look at SystemRescueCD: they boot a Gentoo-based squashed image from CD/USB.

insane.awmn · Post by **insane.awmn** » Thu Aug 16, 2012 2:23 pm

i am booting with a squashfs image with the genkernel ,but i want to try dracut to take advantage the plymooth plugin.
I had try SystemRescueCD before ,and i think that use the genkernel scripts to mount the squashfs image.

devsk · Post by **devsk** » Thu Aug 16, 2012 3:56 pm

insane.awmn wrote:i am booting with a squashfs image with the genkernel ,but i want to try dracut to take advantage the plymooth plugin.
I had try SystemRescueCD before ,and i think that use the genkernel scripts to mount the squashfs image.

Same exact situation here. genkernel has quirks which are irritating.

insane.awmn · Post by **insane.awmn** » Thu Sep 13, 2012 8:37 pm

hello everyone ,

i tested a lot with dracut and finally, i got dracut to boot with the gentoo based squashfs image.
I will get all the infos and i will post where my example for everyone who interesting.

devsk · Post by **devsk** » Thu Sep 13, 2012 10:52 pm

insane.awmn wrote:hello everyone ,

i tested a lot with dracut and finally, i got dracut to boot with the gentoo based squashfs image.
I will get all the infos and i will post where my example for everyone who interesting.

That would be awesome! Thanks!

insane.awmn · Post by **insane.awmn** » Sat Sep 15, 2012 3:40 am

i emerge dracut with DRACUT_MODULES="plymouth dmsquash-live dm lvm" and USE flags="device-mapper "
and inside the chrooted system i run

#dracut -m "base lvm kernel-modules" -a "dmsquash-live" --filesystems "squashfs" -f

This is ganerate the initramfs in /boot

We must have a kernel with lvm support and the LVM kernel extension to permit snapshotting

outside of chrooted enviroment.
we have the directory /diskless/squashfs (contains the rootfs)
we make a folder name LiveOS indside of a folder LiveOS

#mkdir-p /diskless/LiveOS/LiveOS

then go to the directory LiveOS/LiveOS

#cd /diskless/LiveOS/LiveOS

we create an EXT3 image

#dd if=/dev/zero of=ext3fs.img bs=1M count=4096
#mkfs.ext3 ext3fs.img

we create a directory to mount the ext3fs.img

#mkdir -p /diskless/ext3

mount the ext3fs.img to directory
#cd /diskless
mount LiveOS/LiveOS/ext3fs.img ext3/
and then we copy the contents of squashfs-root to ext3 folder
#rsync -avHx squashfs/ --exclude='usr/src/*' ext3
umount the ext3fs.img of ext3/
#umount ext3
go outside of first LiveOS folder
#cd /diskless
make squashfs image
#mksquashfs LiveOS/ squashfs.img
I assume that we have a usb stick formated with fat32 ,and the label of that is " LABEL=live" ,with installed grub or grub2 (personaly i use grub2 with EFI,)
in the /boot folder of usb, we put the initramfs image generated by dracut ,and the kernel for the squashfs-root

the grub kernel command is like that:
/boot/vmlinux-3.3.8-gentoo root=live:LABEL=live ro rd.live.image
Also you can use UUID=aaaa-bbbb instead LABEL="label of usb"

At the usb stick we create the directory /LiveOS and we copy there the squashfs.img
lets assume that the usb is mounted at /mnt/usb
#mkdir /mnt/usb/LiveOS
# cp /diskless/squashfs.img /mnt/usb/LiveOS
if you want to take the advantage of plymouth ,just add in the kernel command the splash or rhgb
/boot/vmlinux-3.3.8-gentoo root=live:LABEL=live ro rd.live.image splash
devsk am waiting your results , i am facing problems with the plymouth (only when is enabled in kernel cmd ) at the shutdown-reboot ,i think that something go wrong with the plymouth-openrc-plugin

(and sorry for my poor english....)

devsk · Post by **devsk** » Sat Sep 15, 2012 3:50 am

So, the module dmsquash-live uses "LiveOS" for the directory at the USB top level and looks for squashfs.img inside to use as root file system?

insane.awmn · Post by **insane.awmn** » Tue Sep 18, 2012 2:51 pm

sorry for my late answer ....

yes...uses the LiveOS directory ,and the squashfs.img is a squashed ext3 image. Do you try it ?

devsk · Post by **devsk** » Wed Sep 19, 2012 2:53 am

insane.awmn wrote:sorry for my late answer ....

yes...uses the LiveOS directory ,and the squashfs.img is a squashed ext3 image. Do you try it ?

Not yet. I am busy with office work at this time and my genkernel setup is working fine across three machines I have (all three boot with the same squashfs image). I will be able to spend time on this in my next upgrade cycle. But thanks so much for posting the step by step guide. I appreciate it.

devsk · Post by **devsk** » Thu Sep 19, 2013 4:24 am

Gets more spooky. 1 year to the date of the last post I made, I still haven't tried this yet. I think its time I do.

jjonline · Post by **jjonline** » Fri Nov 01, 2013 9:28 am

I make and use livecd to boot,I meet same problem,i get the error of "empty or no root= argument".when i use root= such as root=/dev/sr0,then i can see the plymouth work,but dracut sent me a error of "/dev/mappper/live-rw not found",i google a lot,and i think maybe it is a problem of device-mapper or fstab?
I will focus on this.at last,please forgive my poor english.
2013/11/16
today i tried it again,i thought it is a problem about the dracut initramfs don't know how to switch to new root in squashfs image,maybe no squashfs module,but i gen it with dm-squashfs option,and it wasn't work,i will try it again.