INITRAMFS.CONF(5)

🎀 INITRAMFS.CONF(5) 🎀

✨ NAME ✨

okay so this page is all about initramfs.conf, the config file for mkinitramfs 💖 it's basically the settings menu for building your initramfs 🧚

🌸 DESCRIPTION 🌸

bestie, mkinitramfs can totally be customized through its config file, and it's giving main character energy 💅

every line in the file is one of three things: a config variable, a blank line, or a comment. variables get set with a statement that looks like name=[value] 🫶

you can also split your settings into little snippets and drop them in individual files inside /etc/initramfs-tools/conf.d. these get read after the main config file, so you can override stuff without even touching the main file ✨ iconic behavior, no cap 🔥

🌈 GENERAL VARIABLES 🌈

💜 MODULES

• MODULES — this decides which modules go in the initramfs image 🦋
  • list — loads no extra modules at boot, other than the ones in /etc/initramfs-tools/modules and /usr/share/initramfs-tools/modules.d/* (those are always included and loaded early in boot, fr fr)
  • most — adds most file system drivers, plus all ata, sata, scsi and usb drivers 💖
  • dep — tries to guess which modules the running machine actually needs, and only adds those 🧠
  • netboot — adds the base and network modules but skips block devices 🌐
  • the default is most 🍓

🫧 BUSYBOX

• BUSYBOX — includes busybox utilities for the boot scripts 🧸 if you set it to n, mkinitramfs builds an initramfs without busybox. > bestie be careful, lots of boot scripts need those busybox utilities 💀

🗜️ COMPRESS

• COMPRESS — picks the compression method for the initramfs image 🎁 if the kernel doesn't support it (CONFIG_RD) or the matching userspace utility isn't installed, mkinitramfs falls back to gzip 😭

📦 COMPRESSLEVEL

• COMPRESSLEVEL — sets the compression level for the initramfs image 💪 the defaults are 9 for lz4, 9 for zstd, and the builtin defaults for everything else ✨

🔐 UMASK

• UMASK — sets the umask value of the generated initramfs file 🙈 super useful so eventual keys don't get exposed 🔑

🌐 BOOT

• BOOT — lets you boot from an nfs drive as the root 🌙 the default is to boot from local media (hard drive, USB stick) 💾 set it to nfs for an NFS root share 🫶

🧩 RUNSIZE

• RUNSIZE — the size of the /run tmpfs mount point 🎀 you can give it in bytes (suffixes work too) or as a percentage of your physical RAM 📏 it gets used as the value of the size mount option to tmpfs. for the deep dive, check https://www.kernel.org/doc/Documentation/filesystems/tmpfs.txt 📖 you can override it with the optional initramfs.runsize= bootarg 🚀 the default is 10% 💅

🔥 VARIABLES FOR LOCAL BOOT 🔥

💤 RESUME

• RESUME — the device used for suspend-to-disk (hibernation), which the initramfs should try to resume from 🌙 if it's not defined or it's set to auto, mkinitramfs automatically picks the largest available swap partition 🫧 set it to none to turn off resume from disk 🚫

🗂️ FSTYPE

• FSTYPE — the filesystem type(s) to support, separated by commas 📁 if it's not defined or it's set to auto, mkinitramfs detects the current root and /usr filesystem types on its own 🧚

🌍 VARIABLES FOR NFS BOOT 🌍

🦋 DEVICE

• DEVICE — the default network interface to use, like eth0 🔌 the ip or BOOTIF bootargs can override this 💖

🎀 VLAN

• VLAN — sets up the VLAN tag id, e.g. VLAN=eth0.1:eth0 🏷️ the vlan bootarg can override this ✨

🍓 ROOT

• ROOT — lets you hardcode the root bootarg when no root bootarg can be passed 🫶 a real root bootarg always beats this special setting 👑

🛰️ NFSROOT

• NFSROOT — defaults to auto, which picks up the value from the DHCP server 🌈 otherwise you need to specify it as HOST:MOUNT 📡

📂 FILES 📂

• /etc/initramfs-tools/initramfs.conf — the main config file, where all the magic starts 🪄

💌 AUTHOR 💌

the initramfs-tools are written by Maximilian Attems <maks@debian.org>, Jeff Bailey <jbailey@raspberryginger.com> and numerous others 🫶 loosely based on mkinitrd.conf by Herbert Xu 🌸

👀 SEE ALSO 👀

initramfs-tools(7), mkinitramfs(8), update-initramfs(8) ✨

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bestie that's the whole tea ☕💖 initramfs-tools · 2018/07/18 · INITRAMFS.CONF(5) 🦋 stay gorgeous, stay bootable 💅🌈