Collection of IT learning resources
Download complete! Use 'dnf system-upgrade reboot' to start the upgrade.
To remove cached metadata and transaction use 'dnf system-upgrade clean'
The downloaded packages were saved in cache until the next successful transaction.
You can remove cached packages by executing 'dnf clean packages'
To boot an earlier kernel in Fedora, you can use one of the following methods:
Install the python3-dnf-plugins-extras-versionlock package by running the command sudo dnf install python3-dnf-plugins-extras-versionlock. Then add a version lock for the version desired by running the command sudo dnf versionlock add kernel-<version number>¹.
Identify the kernel to be set to boot by default by running the command grubby --info=ALL | grep '^title=' | sed 's/title=//'. Then use the following command to set the default kernel to boot: sudo grubby --set-default-index=<index number>¹.
(1) How to boot an earlier kernel on Fedora - Fedora Magazine. https://fedoramagazine.org/boot-earlier-kernel/. (2) Grub2: How to boot Fedora to an old kernel? - SysTutorials. https://www.systutorials.com/grub2-how-to-boot-fedora-to-an-old-kernel/. (3) Remove older versions of kernel from boot loader in Fedora. https://medium.com/@sulokit/remove-older-versions-of-kernel-from-boot-loader-in-fedora-ce97886e8caa. (4) Manually Upgrading the Kernel :: Fedora Docs. https://docs.fedoraproject.org/en-US/fedora/latest/system-administrators-guide/kernel-module-driver-configuration/Manually_Upgrading_the_Kernel/.
The index number is the number assigned to each kernel in the GRUB menu. You can view the index of any of the kernel listed by running the command grubby --info [kernel-filename] | grep index. For example, if you want to view the index of /boot/vmlinuz-4.18.0-80.11.2.el8_0.x86_64, you can run the command grubby --info /boot/vmlinuz-4.18.0-80.11.2.el8_0.x86_64 | grep index. The output will show you the index number of that kernel¹.
(1) How to Change the default kernel (boot from old kernel … - The Geek Diary. https://www.thegeekdiary.com/how-to-change-the-default-kernel-boot-from-old-kernel-in-centos-rhel-8/. (2) 12 practical grubby command examples (cheat sheet). https://www.golinuxcloud.com/grubby-command-examples/. (3) How to Set Default Entry for the Grub Menu | Baeldung on Linux. https://www.baeldung.com/linux/grub-set-default-entry. (4) Chapter 7. Making persistent changes to the GRUB boot loader. https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/managing_monitoring_and_updating_the_kernel/assembly_making-persistent-changes-to-the-grub-boot-loader_managing-monitoring-and-updating-the-kernel.
sudo groupadd docker
sudo usermod -aG docker $USER
newgrp docker
docker run hello-world