Dracut

Dracut #

Used to create a new initrd or to change the initrd.

Linux manual online voor dracut

Fedore: dracut problems Fedore: grub2

onder Linux #

lsinitrd
dracut -force # maak generic initramfs

Summary of dracut kernel command line options

A selection of the most common debugging related dracut options: rd.shell

Drop to a shell, if the initramfs fails. rd.debug

Set -x for the dracut shell.

rd.break=[cmdline|pre-udev|pre-trigger|initqueue|pre-mount|mount|pre-pivot|cleanup]

Set udev to loglevel info rd.udev.debug

Set udev to loglevel debug

wat kan je allemaal doen #

With rd.break you can stop on several levels in the initrd/initramfs e.g.: rd.break=mount
Now is / gemount mounted on /sysroot as read only
no sys proc dev
no /boot

So what to do?

mount -o remount,rw /sysroot
mount --bind /sys /sysroot/sys
mount --bind /proc /sysroot/proc
mount --bind /dev /sysroot/dev
blkid om te zien waar /boot is
mount /dev/sdax /sysroot/boot
chroot /sysroot

Now you can use dracut to build a new initrd. dracut foobar.img

You can also adjust /etc/default/grub or passwd

This can be used when starting and stop in boot menu.

grub #

See blog rescue a non booting grub

Stop booting in menu and press ‘c’

Now you are in: grub>

There is also a grub rescue mode who is limited in use.

grub> set pager=1

grub> ls
(hd0) (hd0,msdos2) (hd0,msdos1)

grub> ls (hd0,1)
grub> cat (hd0,1)/etc/issue
grub> ls (hd0,gpt2)/

booting from grub #

Some systems do not use prefix /boot

grub> set root=(hd0,1)
grub> linux /boot/vmlinuz-3.13.0-29-generic root=/dev/sda1
grub> initrd /boot/initrd.img-3.13.0-29-generic
grub> boot

In grub-rescue things are used lke this:

grub rescue> set prefix=(hd0,1)/boot/grub
grub rescue> set root=(hd0,1)
grub rescue> insmod normal
grub rescue> normal
grub rescue> insmod linux
grub rescue> linux /boot/vmlinuz-3.13.0-29-generic root=/dev/sda1
grub rescue> initrd /boot/initrd.img-3.13.0-29-generic
grub rescue> boot

Making Permanent Repairs #

See: How do it use ip command

When you have successfully booted your system, run these commands to fix GRUB permanently:

$ update-grub

netwerk activeren #

$ ip a add 192.168.192.91/24 dev eth0
$ ip link set dev eth0 up
$ ip route add default via 192.168.192.1 dev eth0

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