On a Linux system, the initial ramdisk (initrd) is a small filesystem that is used to boot the system. It contains a minimal set of drivers and utilities needed to boot the system, such as the kernel, init, and other essential programs. The initrd is loaded into memory and used to mount the root filesystem and start the system's init process.
To rebuild the initrd on a Linux system, you will need to use the mkinitrd or dracut command. Both of these commands are used to create the initrd image and are usually included with most Linux distributions.
Here's a general outline of the steps you will need to follow to rebuild the initrd using mkinitrd or dracut:
Determine the version of the kernel you are using. You can do this by running the uname -r command.
Run the mkinitrd or dracut command, specifying the kernel version and any other options you want to use.
Here's an example of how to use mkinitrd to rebuild the initrd for the current kernel:
mkinitrd -v /boot/initrd-$(uname -r).img $(uname -r)
Here's an example of how to use dracut to rebuild the initrd for the current kernel:
dracut /boot/initrd-$(uname -r).img $(uname -r)
Once the initrd image has been rebuilt, update the boot loader configuration to use the new initrd image. This may involve modifying the /etc/grub.d/ or /etc/grub.cfg files, or using a tool like grub-mkconfig or grub2-mkconfig.
Reboot the system to use the new initrd image.
It's important to note that rebuilding the initrd may be necessary if you have installed new kernel modules or drivers that need to be included in the initrd image. Consult the mkinitrd and dracut documentation and online resources for more information on how to rebuild the initrd on a Linux system.