On Tue, 2022-03-01 at 14:37 -0700, Chris Murphy wrote:
Summary----------
Most all Fedora variants (except Cloud) have a GRUB menu entry
containing the word "rescue". This kernel+initramfs pair are never
updated for the life of a Fedora installation. And they quickly
become
stale as a Fedora installation ages. This kernel's modules are
eventually deleted, and if selected at boot time, the typical user
experience is a dracut shell.
Basic background-------------
(skip this section if you know how it works)
During a new installation, a single kernel version is installed. e.g.
vmlinuz-5.17.0-0.rc4.96.fc36.x86_64 which is then duplicated as e.g.
vmlinuz-0-rescue-3a86878de5d649a983916543ece7bb7e.
Each of those (identical) kernels has an initramfs file:
initramfs-5.17.0-0.rc4.96.fc36.x86_64.img
initramfs-0-rescue-3a86878de5d649a983916543ece7bb7e.img
The sole difference is the first one is a smaller host-only
initramfs,
the second one is a larger no host-only initramfs created with
`dracut
-N`. The bigger one just contains a bunch of extra kernel modules and
dracut scripts, ostensibly to make it more likely to boot a system
with some change in hardware that the host-only initramfs doesn't
contain. The size of this rescue initramfs is around 100 MiB, with
the
common day to day "host only" initramfs being around 33 MiB. [1]
As the system is updated, additional kernel versions are installed.
dnf.conf contains installonly_limit=3, which results in a maximum of
three kernel versions being installed at a time. Once a fourth kernel
is installed, the first kernel and its modules are removed from
/usr/lib/modules. The rescue kernel+initramfs pair are never updated
or upgraded, even during system upgrades.
Hello,
I found this email on google , thank you for this "basic background"
lesson .
He also have bug report about this [1], in resume we can regenerate
rescue entry just by delete /boot/*-0-rescue-* files and reinstall the
kernel .
But isn't missing inst.rescue boot option [2] ?
I also recently did a scratch to fix this bug [3]
Best regards,
[1]
https://bugzilla.redhat.com/show_bug.cgi?id=1768132
https://bugzilla.redhat.com/show_bug.cgi?id=1768132#c35
[2]
https://github.com/rhinstaller/anaconda/blob/master/docs/boot-options.rst...
[3]
https://src.fedoraproject.org/fork/sergiomb/rpms/dracut/blob/rawhide/f/00...
--
Sérgio M. B.