You know that feeling when everything goes well for a while … until it doesn’t ? been using Fedora Workstation 25 and quite satisfied with it, util one late evening when I decided to clean up old kernels and removed every last kernel available. Here’s how to restore a Fedora Workstation system after you’ve removed every kernel available \ud83d\ude42 this applies to a Fedora 25 on an EFI system and GRUB 2 – so 2017!<\/p>\n
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Normally, at this stage you’d boot the borked system with an USB stick and simply reinstall the kernel packages. This works fine on a Debian\/Ubuntu system, but Fedora seems to be a bit more annoying – after chrooting I’d get:<\/p>\n
\r\n[root@localhost-live ~]# yum -y --disablerepo='*' install kernel-*\r\nRedirecting to '\/usr\/bin\/dnf -y --disablerepo=* install kernel-4.10.8-200.fc25.x86_64.rpm kernel-core-4.10.8-200.fc25.x86_64.rpm kernel-headers-4.10.8-200.fc25.x86_64.rpm kernel-modules-4.10.8-200.fc25.x86_64.rpm' (see 'man yum2dnf')\r\n\r\nerror: Failed to initialize NSS library\r\nTraceback (most recent call last):\r\n File "\/usr\/bin\/dnf", line 57, in <module>\r\n from dnf.cli import main\r\n File "\/usr\/lib\/python3.5\/site-packages\/dnf\/__init__.py", line 31, in <module>\r\n import dnf.base\r\n File "\/usr\/lib\/python3.5\/site-packages\/dnf\/base.py", line 30, in <module>\r\n from dnf.yum import history\r\n File "\/usr\/lib\/python3.5\/site-packages\/dnf\/yum\/history.py", line 31, in <module>\r\n import dnf.rpm.miscutils\r\n File "\/usr\/lib\/python3.5\/site-packages\/dnf\/rpm\/__init__.py", line 22, in <module>\r\n from . import transaction\r\n File "\/usr\/lib\/python3.5\/site-packages\/dnf\/rpm\/transaction.py", line 14, in <module>\r\n import rpm\r\n File "\/usr\/lib64\/python3.5\/site-packages\/rpm\/__init__.py", line 39, in <module>\r\n from rpm.transaction import *\r\n File "\/usr\/lib64\/python3.5\/site-packages\/rpm\/transaction.py", line 5, in <module>\r\n from rpm._rpm import ts as TransactionSetCore\r\nImportError: cannot import name 'ts'\r\n<\/pre>\nWell, f*** you, I don’t remember my package manager needing a ton of Python dependencies to work ! a few more straces and copious amounts of cursing later, here’s the step by step solution:<\/p>\n
1. Boot from a Fedora Workstation 25 Live USB stick. Make sure you click the “Try” option to get your live USB stick mounted read-write, otherwise you won’t be able to install packages on the live USB stick. Make sure the system has network connectivity.<\/p>\n
2. Install the nscd package and its dependencies:<\/p>\n
\r\n# sudo su\r\n# dnf -y install nscd\r\n<\/pre>\n3. Start nscd (this is done in order to have the nscd socket available in chroot, rpm\/dnf won’t work without this – STUPID STUPID STUPID):<\/p>\n
\r\n# systemctl start nscd\r\n<\/pre>\nAfter this, a socket in \/var\/run\/named\/socket should exist.<\/p>\n
4. Prepare the chroot mount point and get inside the chroot:<\/p>\n
\r\n# mkdir \/mnt\/sysimage\r\n# mkdir \/mnt\/sysimage\/{boot,proc,run,sys,dev}\r\n# mount [your root partition] \/mnt\/sysimage\r\n# mount [your boot partition] \/mnt\/sysimage\/boot\r\n# mount --bind \/dev \/mnt\/sysimage\/dev\/\r\n# mount --bind \/sys \/mnt\/sysimage\/sys\/\r\n# mount --bind \/proc \/mnt\/sysimage\/proc\/\r\n# mount --bind \/var\/run \/mnt\/sysimage\/var\/run\r\n# cp \/etc\/resolv.conf \/mnt\/sysimage\/etc\/resolv.conf\r\n<\/pre>\n5. Reinstall the packages by downloading the kernel-* RPMs with wget and installing them manually OR with a “dnf -y reinstall kernel-*” (didn’t tried this one).<\/p>\n
6. Your Grub is now broken too, so we need to rescue it as well. At the GRUB console find your boot and root partitions with “ls” and then:<\/p>\n
\r\n> set prefix=(hdX,Y) \r\n> set root=(hdX,Z)\r\n> linuxefi \/boot\/vmlinuz-4.xxxxxx root=(hdX,Z)\r\n> initramfs \/boot\/initramfs-4.xxxxxx\r\n> boot\r\n<\/pre>\n7. After booting successfully, update GRUB with:<\/p>\n
\r\n# grub2-mkconfig -o \/boot\/efi\/EFI\/fedora\/grub.cfg\r\n<\/pre>\n","protected":false},"excerpt":{"rendered":"