[howto] Gentoo Linux Livecd [last update 01/22/2007]

thedangerouscrew · Tux's lil' helper Joined: 03 Nov 2004 Posts: 110

might be to late but there is a light version of gnome in portage.

I can't tell you much about it though. I'm not a gnome fan

Aszrael · Posted: Fri Feb 03, 2006 8:47 am Post subject:

victorhooi · n00b Joined: 09 Sep 2005 Posts: 13

heya,

A truly great howto

, just a few small questions before I take the dive.

1. Tips for saving space
What sort of things can you do to cut down on size? What stuff is safe to remove? If you're not planning to compile anything, is there anything additional you could remove? (libraries, extraneous compiler fluff etc.)

Also, if you are planning to compile stuff booting from the CD (actually a fairly useful thing - Knoppix has this), what would I need to add? (e.g., basic devel libraries like Ncurses, zlib, libpng etc.)

2. Boot Options for Different WMs
Is it possible to start different window manager's via boot options? (Like Knoppix's "desktop=fluxbox|gnome|icewm|kde|lg3d|larswm" cheatcode, link)

3. Using Knoppix autoconfig/hwsetup
Any thoughts of using the autoconfig/hwesetup scripts from Knoppix/Kanotix? Or the wireless-card setup, or X setup scripts?

4.InitNG
Would there be any advantages to using InitNG? Any special caveats or notes to applying it to this LivecCD? Just a random idea... :wink:

Thanks,
Victor

Lepaca Kliffoth · Posted: Sun Feb 05, 2006 10:19 am Post subject:

thedangerouscrew · Tux's lil' helper Joined: 03 Nov 2004 Posts: 110

I must be missing something here

when I boot my livecd i get "no init found".
i went threw your howto a dozen times and I didn't find anything i did wrong.
so i tried switching the line in isolinux.cfg from linuxrc to /bin/sh and i still get the same error.
when it boots it says it loaded the initrd.

not sure what i did wrong, everything seems straight foward. any ideas would be great help.

btw I'm building a 64bit livecd

Lepaca Kliffoth · Posted: Tue Feb 07, 2006 8:58 am Post subject:

Can you please check again if you included in the kernel built-in support for ext2?
You should also check if in the kernel configuration you set the default initrd size big enough.
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thedangerouscrew · Tux's lil' helper Joined: 03 Nov 2004 Posts: 110

set the image size to 10mb could that be too big?

Lepaca Kliffoth · Posted: Tue Feb 07, 2006 8:34 pm Post subject:

Well it must be bigger than the actual initrd file size. If it still says init not found either you didn't make the linuxrc script executable or you didn't put it inside the initrd at all. It could help if you wrote down and posted the actual error message.
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thedangerouscrew · Tux's lil' helper Joined: 03 Nov 2004 Posts: 110

I scrapped my cd, but the error message pretty much says "no init found use the init= option"

I plan on taking another stab at it.

I wrote this script to create the initrd:

------------------------------------------------------------------------------------------------------------
#!/bin/sh

export LIVEDIR="/home/gentoo/livecd-project/livecd"

echo "creating initrd"
dd if=/dev/zero of=${LIVEDIR}/source/boot/isolinux/initrd bs=1M count=8
losetup /dev/loop0 ${LIVEDIR}/source/boot/isolinux/initrd
mkfs.ext2 /dev/loop0
mount /dev/loop0 initrd

echo "building base"
cd initrd
mkdir etc dev lib bin proc new cdrom static dynamic union sbin
touch linuxrc
chmod +x linuxrc
touch etc/mtab
touch etc/fstab
cd ${LIVEDIR}
cp -v source/bin/sh initrd/bin/
cp -v source/bin/cat initrd/bin/
cp -v source/bin/mount initrd/bin/
cp -v source/bin/umount initrd/bin/
cp -v source/bin/mkdir initrd/bin/
cp -v source/bin/chroot initrd/bin/
cp -v source/bin/tar initrd/bin/
cp -v source/sbin/pivot_root initrd/sbin/

echo "building libraries"
cp -v source/lib/libdl.so.2 initrd/lib/
cp -v source/lib/libc.so.6 initrd/lib/
cp -v source/lib64/ld-linux-x86-64.so.2 initrd/lib/
cp -v source/lib/libblkid.so.1 initrd/lib/
cp -v source/lib/libuuid.so.1 initrd/lib/
cp -v source/lib/libpthread.so.0 initrd/lib/

echo "creating devices"
mknod initrd/dev/console c 5 1
mknod initrd/dev/null c 1 3
mknod initrd/dev/hda b 3 0
mknod initrd/dev/hdb b 3 64
mknod initrd/dev/hdc b 22 0
mknod initrd/dev/hdd b 22 64
mknod initrd/dev/tty c 4 0
mknod initrd/dev/loop0 b 7 0
-----------------------------------------------------------------------------------------------------------------------

I was su to root when I built my cd

do you see anything wrong with it?

the more I think about it I wonder if I forgot to write my /etc/fstab

Lepaca Kliffoth · Posted: Wed Feb 08, 2006 8:00 am Post subject:

At that stage the fstab isn't used at all. Unless you didn't forget to "fill" the linuxrc script there's nothing wrong that I can find in your script. I trust you passed the init=/linuxrc option? You seem experienced enough to not make this mistakes. I don't know what could be wrong

Here's a checklist:

- support for ext2 in the kernel (initrd is formatted in ext2)
- default initrd size set big enough in the kernel config
- options "initrd=initrd init=/linuxrc root=/dev/ram0" added to the kernel commandline
- linuxrc must be executable

That's all as far as I know. Meet those 4 requirements and the initrd should work, then everything's up to the linuxrc script.
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thedangerouscrew · Tux's lil' helper Joined: 03 Nov 2004 Posts: 110

ok i tried making a few livecds and i still get the same error. I have gathered some more information.

things i know:

initrd gets loaded
initrd gets mounted
and dies sometime after that with a kernel panic and the generic no init found error

my guess is that unionfs is not ready for x86_64 yet

i'm going to put some echo coments in the linuxrc script so i can closer figure out where it dies probaly at unionfs
and the init it can't find is probally /sbin/init.

Lepaca Kliffoth · Posted: Sun Feb 12, 2006 12:25 am Post subject:

I'm afraid you're alone on that

I'd really like to help and I hate not being able to.
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thedangerouscrew · Tux's lil' helper Joined: 03 Nov 2004 Posts: 110

just an update

I was wrong it's my initrd. I don't know what i'm doing wrong but I'm making bad initrds.
i tried the dummies version and i still get the same error. If I do a "genkernel initrd"
i can successfully make a live cd without unionfs. i noticed that genkernels initrd is a zipped file
where the ones i make are not. Is the initrd we make here supposed to turn out as a zipped file?
will isolinux and grub only handle zipped initrd?

i do know that my kernel is ok.

any input would be greatly appreciated

thanks

Lepaca Kliffoth · Posted: Tue Feb 14, 2006 12:07 am Post subject:

Genkernel generates an initramfs. That's not the same as an initrd, it's some kind of archive, I think a gzipped cpio archive. I don't know how to make them.
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westboy21 · Posted: Mon Feb 27, 2006 6:43 am Post subject:

Ok, your guide has been wonderful explained up to a certain point. You mention in the guide that you must move /boot into $LIVECD outside of $LIVECD/source. Ok that's cool, but then you say to create the initrd file inside of $LIVECD/source/boot/isolinux/ ... I'm sure this is just a technicality.

My problem at this point, is that I'm getting a kernel panic.

westboy21 · Posted: Mon Feb 27, 2006 7:15 am Post subject:

Well, I found the source of my frustrations. It seems I'd copied over binaries into the ramdisk from my x86_64 installation. Ooops. Guess I better pay attention next time.

Thanks for again for the guide.

Lepaca Kliffoth · Posted: Mon Feb 27, 2006 7:12 pm Post subject:

thedangerouscrew · Tux's lil' helper Joined: 03 Nov 2004 Posts: 110

I figured out my problem with my initrd. when making an initrd for a x86_64 live cd
you need to make a symlink lib64 that points to lib. It took me a while to figure this out and
I feel stupid for not figuring it out sooner. :oops:

Lepaca Kliffoth · Posted: Sat Mar 04, 2006 11:14 pm Post subject:

Thanks thedangerouscrew, I'll put a notice about it somewhere in the guide next time I update (hopefully tomorrow).
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bud1979 · Posted: Tue Mar 14, 2006 4:43 am Post subject:

Hello everyone,

First off thanks for a great guide. I have a bootable CD but have a question I was hoping to get some clarification on.

1. If i umount the /dev directory before i build the cd, I am unable to fully boot the disk. It complains about /dev not having all needed devices. If i add all the devices from my /dev directory to it I can then boot the cd. Any reason for that?

Please let me know if i need to post more information.

I am using qemu to boot the iso, if that matters.

Thanks

Lepaca Kliffoth · Posted: Tue Mar 14, 2006 7:01 am Post subject:

bud1979 · Posted: Wed Mar 15, 2006 12:22 am Post subject:

Ok,

Tried two different ways now. Once with nothing in /dev when cd was made and again with null and console only. Either one does not allow a working boot and comes up with the error of:

Your system seems to be missing critical device files in /dev!
Although you may be running udev or devfs, the root partition is missing
these required files.

One thing I did notice when booting without the files in /dev is that Normally it says Starting Init!--- but without the files in /dev it starts our on hardware detection after about a min or so of hanging on "Found livecd". I installed the new udev 0.86. Is there configuration that I need to do on it as the documentation does not say anthing about it.

Thanks again for the help.

Lepaca Kliffoth · Posted: Wed Mar 15, 2006 11:52 am Post subject:

As far as I know there's no need of any particular udev config to make the boot process work. If you still have problems booting the cd then just fill dev with devices by mounting sys and running udevstart from inside the chroot. It won't create any problem since they will be overwritten at runtime but just to be sure try running the livecd on as many pcs as you can. I don't have anything more to say on this matter, maybe someone else who knows more?
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DVSoftware · n00b Joined: 22 Mar 2006 Posts: 4

hello, i have just burned my first successful livecd ISO (errm... made a mistake with linuxrc not executable)

it works correctly, but... (why always have to be "but"?)

1. ehci-hcd and ohci-hcd are not modprobed on boot causing usb devices being not detected
2. my sound don't work (i'm sure i did compiled kernel module but i'll check, i'm writing this from livecd)
3. my screen resolution is wrong (i get 1280x1024 instead of widescreen 1680x1050 - it's not autodetected by knoppix's app - so is there anything i can do about it? ubuntu detects it for example)

other than that it's working fine
i'm planing to create simple hard disk installation script that will copy entire dvd to hard disk, adding portage and needed stuff