Re: [gentoo-user] Re: kernel choices for booting gentoo as guest in vbox vm

[David Haller]

Hello,

On Thu, 01 Feb 2018, Harry Putnam wrote:
>I did get a screenshot but it is very limited showing only a couple
>dozen lines of the boot messages. (attached at the end.)

Still helps: device 8,65 is /dev/sde1. Check on that ;) E.g. in the
fstab inside the initrd ... And keeping the initrd up-to-date is one
thing genkernel makes easy BTW ;)

Check your bootloader config! Check your initrd. Check your fstab (and
regenerate your initrd if changes concern the root- or resume-device).

>I've never used genkernel, but from what I understand it builds
>everything + the kitchen sink.. so should get the right drivers
>hopefully.

Actually no, you can quite easily configure it to just the tedious
work.

Currently I use this:

1. install new kernel sources (in my case vanilla-sources)
2. copy over old config from last source tree, /boot/, /proc/config.gz
   whatever
3. run 'make oldconfig'
4. optionally note down some new options and then checkup on them using
   'make menuconfig' and searching for the noted options
   it's this step I want to be able to do why I configured genkernel as
   I did (see below)
5. run 'genkernel --kerneldir=. all', but note config below!
6. check /boot/ and /boot/grub*/ if all went right
7. recompile neccessary out-of-tree drivers like e.g.
   x11-drivers/nvidia
8. done

If I just reconfigure, I start at step 4, change the localversion too
in menuconfig. If something breaks, I run 'make clean', save config
and run 'make mrproper' restore config, etc.

==== delcomments /etc/genkernel.conf ====[1]
OLDCONFIG="no"
MENUCONFIG="no"
CLEAN="no"
MRPROPER="no"
MOUNTBOOT="yes"
SYMLINK="yes"
SAVE_CONFIG="yes"
USECOLOR="yes"
LVM="no"
LUKS="no"
GPG="no"
DMRAID="no"
BUSYBOX="yes"
MDADM="no"
MULTIPATH="no"
ISCSI="no"
E2FSPROGS="yes"
ZFS="no"
BTRFS="no"
FIRMWARE="no"
FIRMWARE_DIR="/lib/firmware"
FIRMWARE_FILES=""
DISKLABEL="yes"
BOOTLOADER="grub"
SPLASH="no"
DOKEYMAPAUTO="no"
KEYMAP="0"
GK_SHARE="${GK_SHARE:-/usr/share/genkernel}"
CACHE_DIR="/var/cache/genkernel"
DISTDIR="${GK_SHARE}/distfiles"
LOGFILE="/var/log/genkernel.log"
LOGLEVEL=5
DEFAULT_KERNEL_SOURCE="/usr/src/linux"
BUSYBOX_APPLETS="[ ash sh mount uname echo cut cat mdev switch_root findfs umount unxz xz cpio fsck fdisk halt insmod less lzop makedevs modinfo modprobe reboot"
RAMDISKMODULES="0"
COMPRESS_INITRD="yes"
COMPRESS_INITRD_TYPE="gzip"
WRAP_INITRD=no
====

Of course you must adapt the options for your needs, esp. those for
the initrd if you boot from e.g. a md-device and some such.

I don't actually use the generated initrd, but having them in /boot
with less that 3MB in my case is ok and might come in handy when
something fails.

For me, this has worked nicely the last years. Esp. generating the
grub1 entries and handling the symlinks to the current and last
kernel, initrd and System.map works flawlessly[2].

HTH,
-dnh

[1] delcomments does just that, omit shell-style comments and empty
    lines
====
#!/bin/sed -f
/^[[:space:]]*#/d
/^[[:space:]]*$/d
====

[2] ok, if you manually prune versions from the middle, you'll need to
    set the .old symlinks back to an older version (or the current?),
    haven't checked that yet, but setting it to the previous remaining
    version works nicely.

    I still haven't checked too, if you could have this setup:

====
[options omitted]

title=Gentoo current kernel
  root (hd0,1)
  kernel /boot/kernel OPTIONS...
  [initrd /boot/initramfs]

title=Gentoo old kernel
  root (hd0,1)
  kernel /boot/kernel.old OPTIONS...
  [initrd /boot/initramfs.old]

### <<=== HERE

title=Gentoo Linux (4.15.0-dnh1)
  root (hd0,1)
  kernel /boot/kernel-genkernel-x86_64-4.15.0-dnh1 OPTIONS...
  [initrd /boot/initramfs-genkernel-x86_64-4.15.0-dnh1]

title=Gentoo Linux (4.14.15-dnh1)
  root (hd0,1)
  kernel /boot/kernel-genkernel-x86_64-4.14.15-dnh1 OPTIONS...
  [initrd /boot/initramfs-genkernel-x86_64-4.14.15-dnh1]
...
====

and that new versioned entries would be put at the "HERE" or at the top.

I marked the 'initrd' stuff as optional with the [], as I don't use
an initrd.

And maybe some other boot options (e.g. for another distro or Winders)
sprinkled in at some location.

Anyway, generally genkernel is a great help and occasionally
pruning/reordering entries in the grub1 /boot/grub/menu.lst is easy,
just delete/move stuff around with $EDITOR :)

I never understood why grub2 chucked out the major advantage grub1 had
over lilo: not needing to re-install the boot-sector / stage1 of the
bootloader after every change to the config... Beats me still today.
Which is why I continue to use grub1, which can do all I need (and
more) just nicely. Thank you very much.

-- 
Too bloated to crash, it can only bounce gently into the limits set by
the laws of physics and stop, wobbling slightly.            -- unknown