INITRAMFS.CONF(5) File Formats Manual INITRAMFS.CONF(5)
NAME
initramfs.conf - configuration file for mkinitramfs
DESCRIPTION
The behaviour of mkinitramfs can be modified by its configuration file.
Each line in the file can be a configuration variable, a blank line, or
a comment. The value of an variable is assigned by an statement of the
form: name=[value]
Configuration options can be broken out into configuration snippets and
placed in individual files in the /etc/initramfs-tools/conf.d directory.
Files in this directory are always read after the main configuration
file, so you can override the settings in the main config file without
editing it directly.
GENERAL VARIABLES
MODULES
Specifies the modules for the initramfs image.
Modules listed in /etc/initramfs-tools/modules and
/usr/share/initramfs-tools/modules.d/* are always included in the
initramfs, and are loaded early in the boot process.
list doesn't load any additional modules at boot time, other than
those listed in the above files.
most adds most file system, all ata, sata, scsi and usb drivers.
dep tries to guess which modules are necessary for the running
box and only adds those modules.
netboot adds the base and network modules, but skips block de-
vices.
The default setting is most.
BUSYBOX
Include busybox utilities for the boot scripts. If set to 'n'
mkinitramfs will build an initramfs without busybox. Beware that
many boot scripts need busybox utilities.
KEYMAP
If set to 'y', the console keymap will be loaded during the
initramfs stage. The keymap will anyway be loaded by the
initscripts later, and the packages that might need input will
normally set this variable automatically, so there should nor-
mally be no need to set this.
COMPRESS
Specifies the compression method used for the initramfs image.
mkinitramfs will default to gzip if the kernel lacks support
(CONFIG_RD) or the corresponding userspace utility is not
present.
COMPRESSLEVEL
Specifies the compression level used for the initramfs image.
mkinitramfs will default to 9 for lz4, 9 for zstd, and the
builtin defaults for all others.
UMASK Set the umask value of the generated initramfs file. Useful to
not disclose eventual keys.
BOOT Allows one to use an nfs drive as the root of the drive. The de-
fault is to boot from local media (hard drive, USB stick). Set
to nfs for an NFS root share.
RUNSIZE
The size of the /run tmpfs mount point in bytes (suffixes are
supported) or as percentage of your physical RAM. This parameter
is used as the value of the size mount option to tmpfs. See
https://www.kernel.org/doc/Documentation/filesystems/tmpfs.txt
for details. Can be overridden by an optional initramfs.runsize=
bootarg. The default is 10%.
VARIABLES FOR LOCAL BOOT
RESUME
Specifies the device used for suspend-to-disk (hibernation),
which the initramfs code should attempt to resume from. If this
is not defined or is set to auto, mkinitramfs will automatically
select the largest available swap partition. Set it to none to
disable resume from disk.
FSTYPE
Specifies the filesystem type(s) to support, separated by commas.
If this is not defined or is set to auto, mkinitramfs will auto-
matically detect the current root and /usr filesystem types.
VARIABLES FOR NFS BOOT
DEVICE
Specifies the default network interface to use, like eth0. The
ip or BOOTIF bootargs may override this.
ROOT Allows optional root bootarg hardcoding, when no root bootarg can
be passed. A root bootarg overrides that special setting.
NFSROOT
Defaults to auto in order to pick up value from DHCP server.
Otherwise you need to specify HOST:MOUNT.
FILES
/etc/initramfs-tools/initramfs.conf
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).
initramfs-tools 2018/07/18 INITRAMFS.CONF(5)
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