NAME
mkinitramfs - low-level tool for generating an initramfs image
SYNOPSIS
mkinitramfs [-c compress] [-d confdir] [-k] -o outfile [-r root] [-v]
[version]
mkinitramfs [--supported-host-version= hversion]
mkinitramfs [--supported-target-version= tversion]
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.
-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).
--supported-host-version=hversion
This option queries if mkinitramfs can create ramdisks on a
running kernel of version hversion.
--supported-target-version=tversion
This option queries if mkinitramfs can create ramdisks for
kernel version tversion.
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 /tmp as default value for that purpose. The
given directory should be on a filesystem which allows the execution of
files stored there, i.e. should not be mounted with the noexec mount
option.
FILES
/etc/initramfs-tools/initramfs.conf
The default configuration file for the script. See
initramfs.conf(5) for a description of the available
configuration 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 to hardcode bootargs at initramfs
build time via config snippets. This allows 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(8), update-initramfs(8).