https://lesitedefrancois.be/en/tags/dracut/Recent content in Dracut on Le Site de FrançoisHugo -- gohugo.ioen© 2026 Françoishttps://lesitedefrancois.be/en/security/initramfs/Mon, 01 Jan 0001 00:00:00 +0000https://lesitedefrancois.be/en/security/initramfs/<p><strong>initramfs (initial RAM filesystem)</strong> is the temporary root filesystem the Linux kernel mounts immediately after loading itself and before switching to the machine’s real root. The bootloader — <strong>GRUB</strong>, <strong>systemd-boot</strong>, or firmware loading a <strong>UKI</strong> — passes a compressed <strong>cpio</strong> image (historically called an <em>initrd</em>, though modern Linux always unpacks it as an initramfs into <strong>tmpfs</strong>, not a separate ramdisk block device). The kernel extracts this archive into an in-memory tree, executes <code>/init</code> as pid 1, and that early userspace environment is responsible for everything the bare kernel cannot yet do: loading storage and filesystem kernel modules, bringing up networking, discovering and unlocking <strong>LUKS</strong> volumes, activating <strong>LVM</strong> or multipath devices, mounting the true root partition, and finally calling <code>switch_root</code> (or <code>pivot_root</code>) to hand control to the installed system’s init — typically <strong>systemd</strong> on current distributions. If the initramfs fails, the boot stops before userspace on the real root ever starts; if it succeeds, it is discarded and its memory reclaimed once the pivot completes.</p>