Re: [gentoo-user] Re: installation failure

[Alan McKinnon]

On 17/08/2015 14:07, jfmxl wrote:
> On 2015-08-17 17:20, Martin Vaeth wrote:
>> jfmxl <jfmxl@×××.ORG> wrote:
>>> I wrote a coupla days ago, using the guest interface at the website ...
>>
>> I do not know what you mean by "guest interface".
>> One right place for your support question would be the
>> gentoo forum "Installing Gentoo":
>> https://forums.gentoo.org/viewforum-f-14.html
>>
>
> Thanks for the speedy reply. I got to the 'wrong' place by clicking the
> link to under 'Where to go from here'
> at https://wiki.gentoo.org/wiki/Handbook:AMD64/Installation/Finalizing
> after the machine failed to boot. That led me to
> https://www.gentoo.org/get-involved/mailing-lists/, where the big,
> purple, and welcome 'Post to Gentoo User'
> button caught my eye. It looked inviting, and so I used it.
>
>>> but the kernel failed to mount root.
>>
>> This can have many reasons. More informations are needed.
>> According to this:
>>
>>> looked at /etc/fstab, but found a /dev/ram0 and a
>>> /proc and nothing like what I'd entered ...
>>
>> you are probably using an initrd which you must have built and entered
>> into grub (or grub2?) somewhere. Are you perhaps using genkernel to build
>> such an initrd?
>
>
> https://wiki.gentoo.org/wiki/Handbook:AMD64/Installation/Kernel#Optional:_Building_an_initramfs
>
>
>    To install an initramfs, install sys-kernel/genkernel first, then
> have it generate an initramfs:
>    root #emerge genkernel
>    root #genkernel --install initramfs
>
> So yes, that's what I did, apparently. I was working from one enormously
> long Handbook, and the one I find now is broken into sections, but it
> looks generally the same.  I remembered

Both versions are the same. You can read the handbook as one long page,
or as separate chapters. Same thing either way.

I'm not sure why you are bothering with an initrd to be honest. You are
installing to a qemu guest so the odds are excellent it has one
partition in that file-based disk. You are building Gentoo which is
always done from scratch and has no need of one-size-must-fit-all which
are required for binary distro installers. And you don't seem to be
using exotic boot scenarios either (like LVM on RAID, or booting off
btrfs in a raid configuration.

So hence the question: You have none of the valid reasons why initrds
were introduced, so why are you using one? Just dispense with the entire
thing and take the much simpler route: hard-code into your install
everything it needs to boot. Remember, Gentoo is built from scratch each
time, it has no need to be generic and find out what it's running on
each time it boots, you can simply tell it.

Compile into your kernel (not as modules) each driver you need to boot:

- your hardware chipset
- all the FS types you think you'll use for /

Then:

- keep /usr on the same partition as / (you likely will do this anyway)
- configure your boot loader with a "root=" parameter specifying where
your / is located (do this inside the chroot)

And follow the handbook for everything else.

If you are not already 100% familiar with what kernel module does what,
and what needs to be compiled in, you may end up repeating the booting
off the install CD, mounting the disks, chroot into / process more than
once. Don't lose heart! The learning experience is well worth the
effort, and besides almost every Gentooer goes through this anyway. I
myself have used Gentoo for 10+ years and my most recent manual install
required chrooting FOUR times before I got it right, I was trying to be
clever and short-cut the install process. That never works :-)

genkernel is know to be problematic. List user are in recent times
reporting issues with it that ought not to happen. Other users who use
dracut instead are reporting a much happier experience than with
genkernel. I suppose the handbook needs updating.

....


> Well, I pushed the big friendly purple button and sent off my plea for
> help, and waited and waited, and still have not seen my original post
> appear on this list. You should remove that button if no one bothers to
> moderate the posts it generates. The people who push it get their first
> impression of the 'community' when they are in trouble and are ignored.
> You know what they say about first impressions. Get rid of that button!
> Or read and moderate the posts it generates.

Your original post will not appear, you were not subscribed when you
clicked the button. You need to subscribe first, otherwise the list
rejects the post. All the button does is launch a mailto: link; in a
perfect world the web page would grey out the purple button if you are
not subscribed, but in the real world that page likely has no way to
know if you are or not. Perhaps the page too could be made more obvious
what the requirements are.


All of which highlights something you need to know about Gentoo: arund
here, we start by assuming you know what you are doing mostly and can
think logically. So very little effort is put into detailing every
detail of every step so you never get it wrong. This isn't Apple or
Ubuntu and we're not interested in delivering the perfect
user-experience that fills you with awe, wonder and takes you to
Nirvana. We are interested in giving you tools so you can build what YOU
want. We sorta assume you are comfortable with figuring tools out before
you use them. End result: you get exactly what you want but sometimes
the instructions seem to assume too much, or be a bit vague in places. I
like this, to me it's a wonderful trade-off.


-- 
Alan McKinnon
alan.mckinnon@×××××.com