Re: [blfs-dev] Thinking about a new LFS Live CD/iso

[Tim Tassonis]

On 05/25/16 20:37, Bruce Dubbs wrote:

Tim Tassonis wrote:

Hi Bruce

On 04/18/16 22:24, Bruce Dubbs wrote:

I've been thinking thinking about a new Live CD/Rescue CD based on LFS.
It would be much less ambitious than the old one that included an X
implementation.



If you are interested, I can send you my scripts to do all this, but
maybe
you already have a better solution for all the booting/root disk stuff in
place.


I've dropped the ball on this and am working on other things right now.
One issue I came across in my earlier review was the problem of writable
partitions from a CD/DVD.  It just seems like a kludge.  The old iso is
not capable of being loaded on a thumb drive without some modifications
and I haven't figured that out yet.

I then thought how the CD/DVD paradigm is so last decade.  I think it
would be much easier to produce an iso that targets a thumb drive only.
Users could then add packages as they see fit.

Comments?


A thumb drive solution of of course would be much easier, as you could 
get rid of all the initrd/squashfs stuff. You'd only need two partitions 
on the thumb drive, an iso boot partition which then would mount a 
regular ext4 partition on the same drive by partionid directly, without 
any need of indirection.


I could provide this alternative in the hint too, it's really the 
easiest case, requiring no initrd/squashfs/overlayfs magic.


Kind regards
Tim




   -- Bruce





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Re: [blfs-dev] Thinking about a new LFS Live CD/iso

[Paul J. Hentschel]

On 05/25/16 14:37, Bruce Dubbs wrote:


I then thought how the CD/DVD paradigm is so last decade.  I think it
would be much easier to produce an iso that targets a thumb drive only.
Users could then add packages as they see fit.

Comments?

  -- Bruce




From a user's perspective, I definitely like the idea of targeting a 
thumb drive instead of CD/DVD.


Paul
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Re: [blfs-dev] Thinking about a new LFS Live CD/iso

[Bruce Dubbs]

Tim Tassonis wrote:

Hi Bruce

On 04/18/16 22:24, Bruce Dubbs wrote:

I've been thinking thinking about a new Live CD/Rescue CD based on LFS.
It would be much less ambitious than the old one that included an X
implementation.

What I had in mind is a base LFS system with the following:

dhcpcd
wget
ssh/ssl
which
links
screen
mc
gptfdisk
gpm
LFS HTML
LFS sources tarball

What else?  Other possibilities:
unzip
subversion
git
wireless-tools
wpa-supplicant

   -- Bruce




I have created such a disk, mainly as a rescue disk.

I also added:

- bind, the client parts for nslookup
- net-tools, as I'm just more used to them
- llvm, mdadm, good if used on a system where lvm/RAID is used
- cpio
- pciutils
- parted


In order to create the cd, I also needed:
- libburn, libisoburn, libisofs
- squashfs
- syslinux/isolinux


My approach was to create a cd with isofs that runs a kernel with an
initramfs. The initramfs stuff is pretty identical to the blfs one.

Also on the CD, there is a squashfs file, containing all the stuff you
want on your live system.

In the initramfs's init, I mount the squashfs combined with an overlayfs,
to get a writable root partition, with the writable parts in a tmpfs. This
looks like this:

mknod /dev/loop0 b 7 0
mkdir /.root
mkdir /mnt
mkdir /mnt/gaia-ro
mkdir /mnt/gaia-rw
mount -t tmpfs tmpfs /mnt/gaia-rw
mkdir /mnt/gaia-rw/work
mkdir /mnt/gaia-rw/upper
mkdir /mnt/gaia
mount /gaiarule.sqf  /mnt/gaia-ro -t squashfs -o loop
mount -t overlay overlay
-olowerdir=/mnt/gaia-ro,upperdir=/mnt/gaia-rw/upper,workdir=/mnt/gaia-rw/work
/.root
exec switch_root /.root "$init" "$@"

If you are interested, I can send you my scripts to do all this, but maybe
you already have a better solution for all the booting/root disk stuff in
place.


I've dropped the ball on this and am working on other things right now. 
One issue I came across in my earlier review was the problem of writable 
partitions from a CD/DVD.  It just seems like a kludge.  The old iso is 
not capable of being loaded on a thumb drive without some modifications 
and I haven't figured that out yet.


I then thought how the CD/DVD paradigm is so last decade.  I think it 
would be much easier to produce an iso that targets a thumb drive only. 
Users could then add packages as they see fit.


Comments?

  -- Bruce


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Re: [blfs-dev] Thinking about a new LFS Live CD/iso

[Tim Tassonis]

On 04/19/16 02:54, Bruce Dubbs wrote:

Douglas R. Reno wrote:

This will take me a while.  I have not built a live-dd/iso before and
I'm just researching what is needed now.  I do think a hint would be
appropriate right now, but if everything works out, we might want to add
something to BLFS like the section on Firewalls or Certificates.



As I've done a live/rescue CD based on LFS/BLS and Douglas asked me 
directly about my approach, I thought I'd share how I went about it, and 
why. I'm sure some stuff could be simplified and would of course be glad 
to hear about it.


My goal was to create a rescue CD with everything needed on it, that 
looks like a regular LFS system, e.g. with a writable, ext4 root 
partition. To my knowledge, a kernel can


- either mount a root directly using root=/dev/sd.
- mount an initrd as temporary root using initrd=..

For directly mounting root read/write, there would have to be 
read/writable partition somewhere, which is not the case on a CD. That's 
why I went for the initrd approach.


To get a read/writable root partition, I went for the combined approach 
of squashfs/overlayfs. both natively supported by the kernel. The initrd 
init will mount the squashfs ro and then overlay a tmpfs memory 
filesystem to create the rw root partition.


Whithin the squashfs file, everything you want to use is contained, the 
initial ramdisk will only need the stuff to run the init script, mount 
the squashfs and the overlayfs, and not much else.



So, the sequence of things is:

1. Put everything you want to be on your live CD (including important 
directories, static device files) into a directory, with the right 
permissions etc. The


2. Pack this directory into a squashfs filesystem

3. Create an initrd containing the squashfs and an /init script that 
will mount the squashfs and overlay it with a tmpfs


4. Put isolinux, a kernel, the initrd and a config onto a iso.

5. Test the iso in qemu

6. Burn it on a cd


BLFS stuff you need to create the rescue disk

- cpio, to create the initramfs
- mkinitramfs, to create the initramfs, as in 
http://www.linuxfromscratch.org/blfs/view/svn/postlfs/initramfs.html

- libisoburn to create the image

Stuff outside BLFS you need:

- syslinux 6.03, from http://www.syslinux.org, to create the boot image
- squashfs 4.3 from http://squashfs.sourceforge.net/, to create the squashfs


If there is interest, I will gladly write up a hint, detailing all the 
steps on a working example.



Kind regards
Tim





















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Re: [blfs-dev] Thinking about a new LFS Live CD/iso

[akhiezer]

> From: Tim Tassonis <st...@decentral.ch>
> Date: Wed, 25 May 2016 15:27:01 +0200
> Subject: Re: [blfs-dev] Thinking about a new LFS Live CD/iso
>
> On 04/18/16 22:24, Bruce Dubbs wrote:
.
.
> - llvm, mdadm, good if used on a system where lvm/RAID is used


( - s/l// presumably.)




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Re: [blfs-dev] Thinking about a new LFS Live CD/iso

[Tim Tassonis]

Hi Bruce

On 04/18/16 22:24, Bruce Dubbs wrote:

I've been thinking thinking about a new Live CD/Rescue CD based on LFS.
It would be much less ambitious than the old one that included an X
implementation.

What I had in mind is a base LFS system with the following:

dhcpcd
wget
ssh/ssl
which
links
screen
mc
gptfdisk
gpm
LFS HTML
LFS sources tarball

What else?  Other possibilities:
unzip
subversion
git
wireless-tools
wpa-supplicant

   -- Bruce




I have created such a disk, mainly as a rescue disk.

I also added:

- bind, the client parts for nslookup
- net-tools, as I'm just more used to them
- llvm, mdadm, good if used on a system where lvm/RAID is used
- cpio
- pciutils
- parted


In order to create the cd, I also needed:
- libburn, libisoburn, libisofs
- squashfs
- syslinux/isolinux


My approach was to create a cd with isofs that runs a kernel with an 
initramfs. The initramfs stuff is pretty identical to the blfs one.


Also on the CD, there is a squashfs file, containing all the stuff you 
want on your live system.


In the initramfs's init, I mount the squashfs combined with an 
overlayfs, to get a writable root partition, with the writable parts in 
a tmpfs. This looks like this:


mknod /dev/loop0 b 7 0
mkdir /.root
mkdir /mnt
mkdir /mnt/gaia-ro
mkdir /mnt/gaia-rw
mount -t tmpfs tmpfs /mnt/gaia-rw
mkdir /mnt/gaia-rw/work
mkdir /mnt/gaia-rw/upper
mkdir /mnt/gaia
mount /gaiarule.sqf  /mnt/gaia-ro -t squashfs -o loop
mount -t overlay overlay 
-olowerdir=/mnt/gaia-ro,upperdir=/mnt/gaia-rw/upper,workdir=/mnt/gaia-rw/work 
/.root

exec switch_root /.root "$init" "$@"

If you are interested, I can send you my scripts to do all this, but 
maybe you already have a better solution for all the booting/root disk 
stuff in place.


Kind regards
Tim







--
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Tim Tassonis
Dennlerstasse 36
8047 Zürich

st...@decentral.ch
+41 79 229 36 17
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Re: [blfs-dev] Thinking about a new LFS Live CD/iso

[Bruce Dubbs]

Douglas R. Reno wrote:

On Mon, Apr 18, 2016 at 5:51 PM, Bruce Dubbs  wrote:


Douglas R. Reno wrote:



I have had that idea for a long time actually. I would add stuff like



pciutils, usbutils, hdparm, sg3_utils, ntfs-3g, parted, etc. to make it a
more complete testing/rescue platform



Seems reasonable.

[snip]

I think that

unzip, subversion, git, wireless-tools, and wpa-supplicant would be
useful,



Will the LiveCD need an initramfs to boot?




No, but the kernel will be fairly large.  It is not intended to support
everything though.  Just a typical x86_64 based system starting to a
virtual screen.

OK, that makes sense. If you decide to script the build, can you send me a

copy of the files? I would like to make a systemd adaptation just to prove
that it can be done (that would include the systemd book and sources, as
well as the kernel options necessary for it and systemd itself... could be
used for reading the journal of a failed system and recovering it).


This will take me a while.  I have not built a live-dd/iso before and I'm 
just researching what is needed now.  I do think a hint would be 
appropriate right now, but if everything works out, we might want to add 
something to BLFS like the section on Firewalls or Certificates.


  -- Bruce


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Re: [blfs-dev] Thinking about a new LFS Live CD/iso

[Douglas R. Reno]

On Mon, Apr 18, 2016 at 3:24 PM, Bruce Dubbs  wrote:

> I've been thinking thinking about a new Live CD/Rescue CD based on LFS. It
> would be much less ambitious than the old one that included an X
> implementation.
>
> What I had in mind is a base LFS system with the following:
>
> dhcpcd
> wget
> ssh/ssl
> which
> links
> screen
> mc
> gptfdisk
> gpm
> LFS HTML
> LFS sources tarball
>
> What else?  Other possibilities:
> unzip
> subversion
> git
> wireless-tools
> wpa-supplicant
>
>   -- Bruce
>
> I have had that idea for a long time actually. I would add stuff like
pciutils, usbutils, hdparm, sg3_utils, ntfs-3g, parted, etc. to make it a
more complete testing/rescue platform (and the ntfs-3g comes from my
personal experience, since I use it regularly because I have a copy of my
sources on a USB External Hard Drive that I copy over when needed on a new
system).  The pciutils and usbutils could be used to aid the user in
knowing what to enable in the kernel before building it. I think that
unzip, subversion, git, wireless-tools, and wpa-supplicant would be useful,
however I would also add a copy of the latest jhalfs snapshot into that as
well. It wouldn't be a bad idea to add all of the other filesystem programs
that we have into the book into the LiveCD as well, as those could help
recover a broken filesystem. If anyone uses MD RAID or LVM, I can see
adding those utilities to the LiveCD helping them rescue a system. If a
person is trying to determine whether or not their system is running too
hot, lm_sensors could help out there. smartmontools would be incredibly
useful as well, seeing as it could allow a person to run a test on their
hard drive and/or find out whether or not the SMART data is reporting that
it is failing. Might want to add Sudo as well, seeing as jhalfs needs it.

Another thing... were you going to use OpenSSL or GnuTLS for wget? If I
remember correctly, we had some problems with OpenSSL and Wget, and that is
why the book recommends GnuTLS.

Will the LiveCD need an initramfs to boot?

This is a great idea!

Douglas R. Reno
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[blfs-dev] Thinking about a new LFS Live CD/iso

[Bruce Dubbs]

I've been thinking thinking about a new Live CD/Rescue CD based on LFS. 
It would be much less ambitious than the old one that included an X 
implementation.


What I had in mind is a base LFS system with the following:

dhcpcd
wget
ssh/ssl
which
links
screen
mc
gptfdisk
gpm
LFS HTML
LFS sources tarball

What else?  Other possibilities:
unzip
subversion
git
wireless-tools
wpa-supplicant

  -- Bruce

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