[SOLVED]Can we use our own kernels to produce an initramfs

rurouni_hou_ou

I have compiled vanilla kernels on another distro before and in the config I tell it to build an initramfs. It makes it and installs it to the system fine with the initramfs.

Although, when reading the section on installing the kernel in the installation guide, it tells me to use genkernel to generate one. Now I'll be frank, I don't want to use genkernel, I'd prefer to use one generated in my gentoo-sources config. Is it sane to use

John R. Graham · Posted: Tue Aug 26, 2014 8:02 pm Post subject:

You can use genkernel to build against your own kernel config. See the --oldconfig command line option and the corresponding OLDCONFIG option in /etc/genkernel.conf. Simple as that.

Furthermore, genkernel does use the installed kernel sources at the /usr/src/linux symlink location as the kernel to build, so, if you have gentoo-sources installed, that's what it uses. It's only the .config file that's by default ignored in favor of a genkernel-provided "kitchen sink" .config file.

- John
_________________
I can confirm that I have received between 0 and 499 National Security Letters.

rurouni_hou_ou · Posted: Tue Aug 26, 2014 8:21 pm Post subject:

So genkernel is used as a front-end for building a 'kitchen-sink' kernel, and it can be directed to use my config. So that means it would use the same initramfs settings as my config. So it is safe to ignore genkernel if I want to. Thanks, I've learnt about genkernel in more depth

The Doctor · Moderator Joined: 27 Jul 2010 Posts: 2678

I think a good question here would be why you want one. A custom kernel should be able to boot just fine without one.

And of course, there is no reason why you could roll one yourself to do exactly what you need and would not depend on the kernel version at all.
_________________
First things first, but not necessarily in that order.

Apologies if I take a while to respond. I'm currently working on the dematerialization circuit for my blue box.

rurouni_hou_ou · Posted: Tue Aug 26, 2014 9:27 pm Post subject:

The Doctor · Moderator Joined: 27 Jul 2010 Posts: 2678

No, that is fine. The only partition that might cause you problems is if /usr is a separate partition. Otherwise, your fine.
_________________
First things first, but not necessarily in that order.

Apologies if I take a while to respond. I'm currently working on the dematerialization circuit for my blue box.

NeddySeagoon · Posted: Tue Aug 26, 2014 9:33 pm Post subject:

rurouni_hou_ou,

Neither /boot nor /home are needed to boot.
That sounds odd because your boot loader reads /boot, not the kernel.

Provided everything needed to mount the root filesystem is built into the kernel you do not need an initrd.
Currently you only need an initrd if /usr is not on the root partition.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

rurouni_hou_ou · Posted: Tue Aug 26, 2014 9:39 pm Post subject:

I read somewhere that you needed an initramfs if you had stuff mounted on other partitions. What I did not realize and not do is that it is only for /usr. Thank you for the pointer. I clearly wasn't thinking about the requirements properly. Problem eliminated. Thanks :wink:

saellaven · l33t Joined: 23 Jul 2006 Posts: 646

NeddySeagoon · Posted: Wed Aug 27, 2014 4:03 pm Post subject:

saellaven,

I'm aware of that post by steveL.

I have everything except /boot in LVM on top of raid5, so I need an initrd to assemble the raid and start LVM before my root is even visible.
Going on to mount /usr is only a small addition to the initrd.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

saellaven · l33t Joined: 23 Jul 2006 Posts: 646