MKINITRAMFS(8) System Administration MKINITRAMFS(8)
NAME
mkinitramfs - low-level tool for generating an initramfs image
SYNOPSIS
mkinitramfs [option]... -o outfile [version]
mkinitramfs -h
DESCRIPTION
The mkinitramfs script generates an initramfs image. The initramfs is
a compressed cpio archive. The archive can be used on a different box
of the same arch with the corresponding Linux kernel. mkinitramfs is
meant for advanced usage. On your local box update-initramfs calls
mkinitramfs with the relevant parameters. update-initramfs keeps
sha1sum of generated initramfs. It takes care to generate backups and
eventually runs the bootloader.
At boot time, the kernel unpacks that archive into RAM disk, mounts and
uses it as initial root file system. All finding of the root device
happens in this early userspace.
OPTIONS
-c compress
Override the COMPRESS setting in initramfs.conf.
-d confdir
Set an alternate configuration directory.
-k Keep the temporary directory used to make the image.
-l compresslevel
Override the COMPRESSLEVEL setting in initramfs.conf.
-o outfile
Write the image to outfile.
-r root
Override the ROOT setting in initramfs.conf.
-v Set the verbose mode output.
version
Set the kernel version of the initramfs image (defaults to the
running kernel).
-h, --help
Display usage information and exit.
ENVIRONMENT
mkinitramfs honours the TMPDIR environment variable. If set, it uses
subdirectories in the given directory to create its temporary working
directories. Else it uses /var/tmp as default value for that purpose.
The given directory should be on a filesystem which allows the execu-
tion of files stored there, i.e. should not be mounted with the noexec
mount option.
If SOURCE_DATE_EPOCH is set, mkinitramfs attempts to generate a repro-
ducible initramfs image.
FILES
/etc/initramfs-tools/initramfs.conf
The default configuration file for the script. See
initramfs.conf(5) for a description of the available configura-
tion parameter.
/etc/initramfs-tools/modules
Specified modules will be put in the generated image and loaded
when the system boots. The format - one per line - is identical
to that of /etc/modules, which is described in modules(5).
/etc/initramfs-tools/conf.d
The conf.d directory allows one to hardcode bootargs at
initramfs build time via config snippets. This allows one to set
ROOT or RESUME. This is especially useful for bootloaders,
which do not pass an root bootarg.
/etc/initramfs-tools/DSDT.aml
If this file exists, it will be appended to the initramfs in a
way that causes it to be loaded by ACPI.
EXAMPLES
Create an initramfs for current running kernel:
mkinitramfs -o ~/tmp/initramfs-$(uname -r)
Create an initramfs for specific kernel and keep builddirs:
mkinitramfs -k -o ~/tmp/initramfs-2.6.21-686 2.6.21-686
Debug initramfs creation (check out written logfile)
sh -x mkinitramfs -o ~/tmp/initramfs-$(uname -r) 2> ~/tmp/log
AUTHOR
The initramfs-tools are written by Maximilian Attems <maks@debian.org>,
Jeff Bailey <jbailey@raspberryginger.com> and numerous others.
SEE ALSO
initramfs.conf(5), initramfs-tools(7), update-initramfs(8),
lsinitramfs(8), unmkinitramfs(8).
initramfs-tools 2018/07/18 MKINITRAMFS(8)
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