Reboot
Livepatch: Linux kernel updates without rebooting
Livepatch is a feature to do live kernel patching for Linux systems. It allows applying security updates without rebooting the system. Learn how it works!
Summary
If you run a Linux server, software patching is a task that will have to be performed on a regular basis. Although most programs can be auto-restarted with a tool like needrestart, there is one exception: the kernel.
Wouldn’t it be a nice if we could update the kernel without the mandatory reboot? Here is livepatch, the feature of the Linux kernel that makes it possible. Let’s discover how it works and if you can use it on your system.
How to check if your Arch Linux system needs a reboot
Want to check if a reboot of the system is needed on Arch Linux? Here is how that can be done including the relevant commands.
Summary
By default Arch will install the kernel in /boot with the name vmlinuz-linux. To determine if the system is running the latest kernel, we can compare the running kernel and the one on disk.
Running kernel
One way to determine the running kernel is with the uname command. By default installed and with the -r parameter it will provide the kernel release version.
# uname -r
3.17.4-1-ARCH
Kernel on disk
Checking the latest kernel on disk is almost as easy. In this case we have to analyze the /boot/vmlinuz-linux file, which is the default file name for the Linux kernel on Arch Linux.
Check for a required reboot on Debian and Ubuntu systems
Debian based systems, like Ubuntu, need sometimes a reboot as well. We have a look on determining if a required reboot is needed and due to what packages.
Summary
Administrators of Debian-based systems know they have to reboot their systems, just like any other Linux distribution. However, why is the reboot needed? Could we monitor for which systems need an actual reboot?
Required restart required?
This Ubuntu system needs a restart
Required reboot
Software can contain issues, which we call bugs. Most bugs are just annoying if you encounter them and can be fixed by upgrading to a newer version of the software. Other bugs are special in the way that they may leak sensitive data or allow unauthorized access to the software or system. These type of bugs are called vulnerabilities.