Re: [gentoo-user] Re: Question about genkernel's default kernel config

[J. Roeleveld]

On Monday, August 15, 2016 04:32:29 AM Rich Freeman wrote:
> On Mon, Aug 15, 2016 at 4:10 AM, J. Roeleveld <joost@××××××××.org> wrote:
> > The ones created by genkernel or dracut always need a few iterations
> > before
> > they work semi-reliably and are not flexible enough.
> > I have 2 disks in my laptop. Both are encrypted using LUKS and the same
> > passphrase. Neither genkernel nor dracut have the intelligence to ask me
> > once and try the key on both, only asking for a 2nd key when the provided
> > one doesn't work for both.
> >
> > I ended up writing my own, which has proven more reliable and stable. The
> > reduced size also makes maintenance less of an issue.
>
> Nothing wrong with this if you know what you're doing.  Dracut is
> designed to be one-size-fits-all with a lot of logic to figure out
> what your system needs to boot.
>
> It is also somewhat dependent on a correct fstab.  Don't take that for
> granted: the kernel doesn't look at fstab at all when mounting root,
> and neither do most of the other tools, so if your root partition
> isn't correctly defined in fstab you might never know it and dracut
> will get confused.  If nothing else once it does have it correctly
> mounted it will read fstab and then mess it up when it re-mounts root
> per "your" instructions.

I understand what you're saying. Except in my case, that wasn't the cause.

> If you just need to tweak dracut behavior you may be better off with a
> dracut module.  They're just shell scripts and pretty simple to write.
> That lets you tweak something at some point during boot without having
> to build the entire thing yourself.

This actually had (or has, not bothered to check current status) a distinct 
lack of usable documentation. Looking for clear howto's on creating my own 
(embedded into the kernel) initramfs was a lot quicker.

> And since it uses udev it is fairly robust against things like adding
> a drive and now the kernel re-letters everything.

If I were using normal partitioning, I wouldn't need an initramfs.

> If you tweak it to use the same password for all drives I wouldn't be
> surprised if upstream accepts the patch...

If it were properly documented where it does this, I would be willing to try.
Right now, my init-script is 45 lines (including white-space)

My laptop has 2 disks. Both are fully encrypted (apart from a small /boot).
On top of the encrypted parts I have LVM, which contains my partitions.

It asks for a password, decrypts both drives, enables LVM, checks if it needs 
to resume from "suspend to disk", if not, mounts the partitions and boots. If 
it does need to resume, it simply resumes.
If it fails anywhere, it drops me into a busybox shell.

I can then simply "cat" the init script to see what commands I need to run to 
boot, replacing anything that is no longer valid.

With dracut and genkernel, the init-script is too convoluted to simply follow. 
Which means it is not allowed to fail.

--
Joost