Provided by: systemd-repart_256.5-2ubuntu3.1_amd64 
NAME
systemd-repart, systemd-repart.service - Automatically grow and add partitions
SYNOPSIS
systemd-repart [OPTIONS...] [[BLOCKDEVICE]...]
systemd-repart.service
DESCRIPTION
systemd-repart creates partition tables, and adds or grows partitions, based on the
configuration files described in repart.d(5).
systemd-repart is used when building OS images, and also when deploying images to
automatically adjust them, during boot, to the system they are running on. This way the
image can be minimal in size and may be augmented automatically at boot, taking possession
of the disk space available.
If invoked with no arguments, systemd-repart operates on the block device backing the root
file system partition of the running OS, thus adding and growing partitions of the booted
OS itself. When called in the initrd, it operates on the block device backing /sysroot/
instead, i.e. on the block device the system will soon transition into. If --image= is
used, it will operate on the specified device or image file. The systemd-repart.service
service is generally run at boot in the initrd, in order to augment the partition table of
the OS before its partitions are mounted.
systemd-repart operations are mostly incremental: it grows existing partitions or adds new
ones, but does not shrink, delete, or move existing partitions. The service is intended to
be run on every boot, but when it detects that the partition table already matches the
installed repart.d/*.conf configuration files, it executes no operation.
The following use cases are among those covered:
• The root partition may be grown to cover the whole available disk space.
• A /home/, swap, or /srv/ partition can be added.
• A second (or third, ...) root partition may be added, to cover A/B style setups where
a second version of the root file system is alternatingly used for implementing update
schemes. The deployed image would carry only a single partition ("A") but on first
boot a second partition ("B") for this purpose is automatically created.
The algorithm executed by systemd-repart is roughly as follows:
1. The repart.d/*.conf configuration files are loaded and parsed, and ordered by filename
(without the directory prefix). For each configuration file, drop-in files are loaded
from directories with same name as the configuration file with the suffix ".d" added.
2. The partition table on the block device is loaded and parsed, if present.
3. The existing partitions in the partition table are matched with the repart.d/*.conf
files by GPT partition type UUID. The first existing partition of a specific type is
assigned the first configuration file declaring the same type. The second existing
partition of a specific type is then assigned the second configuration file declaring
the same type, and so on. After this iterative assigning is complete, any existing
partitions that have no matching configuration file are considered "foreign" and left
as they are. And any configuration files for which no partition was matched are
treated as requests to create a partition.
4. Partitions that shall be created are now allocated on the disk, taking the size
constraints and weights declared in the configuration files into account. Free space
is used within the limits set by size and padding requests. In addition, existing
partitions that should be grown are grown. New partitions are always appended to the
end of the partition table, taking the first partition table slot whose index is
greater than the indexes of all existing partitions. Partitions are never reordered
and thus partition numbers remain stable. When partitions are created, they are placed
in the smallest area of free space that is large enough to satisfy the size and
padding limits. This means that partitions might have different order on disk than in
the partition table. Note that this allocation happens in memory only, the partition
table on disk is not updated yet.
5. All existing partitions for which configuration files exist and which currently have
no GPT partition label set will be assigned a label, either explicitly configured in
the configuration or — if that's missing — derived automatically from the partition
type. The same is done for all partitions that are newly created. These assignments
are done in memory only, too, the disk is not updated yet.
6. Similarly, all existing partitions for which configuration files exist and which
currently have an all-zero identifying UUID will be assigned a new UUID. This UUID is
cryptographically hashed from a common seed value together with the partition type
UUID (and a counter in case multiple partitions of the same type are defined), see
below. The same is done for all partitions that are created anew. These assignments
are done in memory only, too, the disk is not updated yet.
7. Similarly, if the disk's volume UUID is all zeroes it is also initialized, also
cryptographically hashed from the same common seed value. This is done in memory only
too.
8. The disk space assigned to new partitions (i.e. what was previously free space) is now
erased. Specifically, all file system signatures are removed, and if the device
supports it, the BLKDISCARD I/O control command is issued to inform the hardware that
the space is now empty. In addition any "padding" between partitions and at the end of
the device is similarly erased.
9. The new partition table is finally written to disk. The kernel is asked to reread the
partition table.
As an exception to the normal incremental operation, when called in a special "factory
reset" mode, systemd-repart may be used to erase existing partitions to reset an
installation back to vendor defaults. This mode of operation is used when either the
--factory-reset=yes switch is passed on the tool's command line, or the
systemd.factory_reset=yes option is specified on the kernel command line, or the
FactoryReset EFI variable (vendor UUID 8cf2644b-4b0b-428f-9387-6d876050dc67) is set to
"yes". It alters the algorithm above slightly: between the 3rd and the 4th step above any
partition marked explicitly via the FactoryReset= boolean is deleted, and the algorithm
restarted, thus immediately re-creating these partitions anew empty.
Note that systemd-repart by default only changes partition tables, it does not create or
resize any file systems within these partitions, unless the Format= configuration option
is specified. Also note that there are also separate mechanisms available for this
purpose, for example systemd-growfs(8) and systemd-makefs.
The UUIDs identifying the new partitions created (or assigned to existing partitions that
have no UUID yet), as well as the disk as a whole are hashed cryptographically from a
common seed value. This seed value is usually the machine-id(5) of the system, so that the
machine ID reproducibly determines the UUIDs assigned to all partitions. If the machine ID
cannot be read (or the user passes --seed=random, see below) the seed is generated
randomly instead, so that the partition UUIDs are also effectively random. The seed value
may also be set explicitly, formatted as UUID via the --seed= option. By hashing these
UUIDs from a common seed images prepared with this tool become reproducible and the result
of the algorithm above deterministic.
The positional argument should specify the block device or a regular file to operate on.
If --empty=create is specified, the specified path is created as regular file, which is
useful for generating disk images from scratch.
OPTIONS
The following options are understood:
--dry-run=
Takes a boolean. If this switch is not specified --dry-run=yes is the implied default.
Controls whether systemd-repart executes the requested re-partition operations or
whether it should only show what it would do. Unless --dry-run=no is specified
systemd-repart will not actually touch the device's partition table.
Added in version 245.
--empty=
Takes one of "refuse", "allow", "require", "force" or "create". Controls how to
operate on block devices that are entirely empty, i.e. carry no partition table/disk
label yet. If this switch is not specified the implied default is "refuse".
If "refuse" systemd-repart requires that the block device it shall operate on already
carries a partition table and refuses operation if none is found. If "allow" the
command will extend an existing partition table or create a new one if none exists. If
"require" the command will create a new partition table if none exists so far, and
refuse operation if one already exists. If "force" it will create a fresh partition
table unconditionally, erasing the disk fully in effect. If "force" no existing
partitions will be taken into account or survive the operation. Hence: use with care,
this is a great way to lose all your data. If "create" a new loopback file is create
under the path passed via the device node parameter, of the size indicated with
--size=, see below.
Added in version 245.
--discard=
Takes a boolean. If this switch is not specified --discard=yes is the implied default.
Controls whether to issue the BLKDISCARD I/O control command on the space taken up by
any added partitions or on the space in between them. Usually, it's a good idea to
issue this request since it tells the underlying hardware that the covered blocks
shall be considered empty, improving performance. If operating on a regular file
instead of a block device node, a sparse file is generated.
Added in version 245.
--size=
Takes a size in bytes, using the usual K, M, G, T suffixes, or the special value
"auto". If used the specified device node path must refer to a regular file, which is
then grown to the specified size if smaller, before any change is made to the
partition table. If specified as "auto" the minimal size for the disk image is
automatically determined (i.e. the minimal sizes of all partitions are summed up,
taking space for additional metadata into account). This switch is not supported if
the specified node is a block device. This switch has no effect if the file is already
as large as the specified size or larger. The specified size is implicitly rounded up
to multiples of 4096. When used with --empty=create this specifies the initial size of
the loopback file to create.
The --size=auto option takes the sizes of pre-existing partitions into account.
However, it does not accommodate for partition tables that are not tightly packed: the
configured partitions might still not fit into the backing device if empty space
exists between pre-existing partitions (or before the first partition) that cannot be
fully filled by partitions to grow or create.
Also note that the automatic size determination does not take files or directories
specified with CopyFiles= into account: operation might fail if the specified files or
directories require more disk space then the configured per-partition minimal size
limit.
Added in version 246.
--factory-reset=
Takes boolean. If this switch is not specified --factory=reset=no is the implied
default. Controls whether to operate in "factory reset" mode, see above. If set to
true this will remove all existing partitions marked with FactoryReset= set to yes
early while executing the re-partitioning algorithm. Use with care, this is a great
way to lose all your data. Note that partition files need to explicitly turn
FactoryReset= on, as the option defaults to off. If no partitions are marked for
factory reset this switch has no effect. Note that there are two other methods to
request factory reset operation: via the kernel command line and via an EFI variable,
see above.
Added in version 245.
--can-factory-reset
If this switch is specified the disk is not re-partitioned. Instead it is determined
if any existing partitions are marked with FactoryReset=. If there are the tool will
exit with exit status zero, otherwise non-zero. This switch may be used to quickly
determine whether the running system supports a factory reset mechanism built on
systemd-repart.
Added in version 245.
--root=
Takes a path to a directory to use as root file system when searching for
repart.d/*.conf files, for the machine ID file to use as seed and for the CopyFiles=
and CopyBlocks= source files and directories. By default when invoked on the regular
system this defaults to the host's root file system /. If invoked from the initrd this
defaults to /sysroot/, so that the tool operates on the configuration and machine ID
stored in the root file system later transitioned into itself.
See --copy-source= for a more restricted option that only affects CopyFiles=.
Added in version 245.
--image=
Takes a path to a disk image file or device to mount and use in a similar fashion to
--root=, see above.
Added in version 249.
--image-policy=policy
Takes an image policy string as argument, as per systemd.image-policy(7). The policy
is enforced when operating on the disk image specified via --image=, see above. If not
specified defaults to the "*" policy, i.e. all recognized file systems in the image
are used.
--seed=
Takes a UUID as argument or the special value random. If a UUID is specified the UUIDs
to assign to partitions and the partition table itself are derived via cryptographic
hashing from it. If not specified it is attempted to read the machine ID from the host
(or more precisely, the root directory configured via --root=) and use it as seed
instead, falling back to a randomized seed otherwise. Use --seed=random to force a
randomized seed. Explicitly specifying the seed may be used to generated strictly
reproducible partition tables.
Added in version 245.
--pretty=
Takes a boolean argument. If this switch is not specified, it defaults to on when
called from an interactive terminal and off otherwise. Controls whether to show a user
friendly table and graphic illustrating the changes applied.
Added in version 245.
--definitions=
Takes a file system path. If specified the *.conf files are read from the specified
directory instead of searching in /usr/lib/repart.d/*.conf, /etc/repart.d/*.conf,
/run/repart.d/*.conf.
This parameter can be specified multiple times.
Added in version 245.
--key-file=
Takes a file system path. Configures the encryption key to use when setting up LUKS2
volumes configured with the Encrypt=key-file setting in partition files. Should refer
to a regular file containing the key, or an AF_UNIX stream socket in the file system.
In the latter case a connection is made to it and the key read from it. If this switch
is not specified the empty key (i.e. zero length key) is used. This behaviour is
useful for setting up encrypted partitions during early first boot that receive their
user-supplied password only in a later setup step.
Added in version 247.
--private-key=
Takes a file system path. Configures the signing key to use when creating verity
signature partitions with the Verity=signature setting in partition files.
Added in version 252.
--private-key-source=
Takes one of "file", "engine" or "provider". In the latter two cases, it is followed
by the name of a provider or engine, separated by colon, that will be passed to
OpenSSL's "engine" or "provider" logic. Configures the signing mechanism to use when
creating verity signature partitions with the Verity=signature setting in partition
files.
Added in version 256.
--certificate=
Takes a file system path. Configures the PEM encoded X.509 certificate to use when
creating verity signature partitions with the Verity=signature setting in partition
files.
Added in version 252.
--tpm2-device=, --tpm2-pcrs=
Configures the TPM2 device and list of PCRs to use for LUKS2 volumes configured with
the Encrypt=tpm2 option. These options take the same parameters as the identically
named options to systemd-cryptenroll(1) and have the same effect on partitions where
TPM2 enrollment is requested.
Added in version 248.
--tpm2-device-key=PATH, --tpm2-seal-key-handle=HANDLE
Configures a TPM2 SRK key to bind encryption to. See systemd-cryptenroll(1) for
details on this option.
Added in version 255.
--tpm2-public-key=PATH, --tpm2-public-key-pcrs=PCR[+PCR...]
Configures a TPM2 signed PCR policy to bind encryption to. See systemd-cryptenroll(1)
for details on these two options.
Added in version 252.
--tpm2-pcrlock=PATH
Configures a TPM2 pcrlock policy to bind encryption to. See systemd-cryptenroll(1) for
details on this option.
Added in version 255.
--split=BOOL
Enables generation of split artifacts from partitions configured with SplitName=. If
enabled, for each partition with SplitName= set, a separate output file containing
just the contents of that partition is generated. The output filename consists of the
loopback filename suffixed with the name configured with SplitName=. If the loopback
filename ends with ".raw", the suffix is inserted before the ".raw" extension instead.
Note that --split is independent from --dry-run. Even if --dry-run is enabled, split
artifacts will still be generated from an existing image if --split is enabled.
Added in version 252.
--include-partitions=PARTITIONS, --exclude-partitions=PARTITIONS
These options specify which partition types systemd-repart should operate on. If
--include-partitions= is used, all partitions that aren't specified are excluded. If
--exclude-partitions= is used, all partitions that are specified are excluded. Both
options take a comma separated list of GPT partition type UUIDs or identifiers (see
Type= in repart.d(5)).
Added in version 253.
--defer-partitions=PARTITIONS
This option specifies for which partition types systemd-repart should defer. All
partitions that are deferred using this option are still taken into account when
calculating the sizes and offsets of other partitions, but aren't actually written to
the disk image. The net effect of this option is that if you run systemd-repart again
without this option, the missing partitions will be added as if they had not been
deferred the first time systemd-repart was executed.
Added in version 253.
--sector-size=BYTES
This option allows configuring the sector size of the image produced by
systemd-repart. It takes a value that is a power of "2" between "512" and "4096". This
option is useful when building images for disks that use a different sector size as
the disk on which the image is produced.
Added in version 253.
--architecture=ARCH
This option allows overriding the architecture used for architecture specific
partition types. For example, if set to "arm64" a partition type of "root-x86-64"
referenced in repart.d/ drop-ins will be patched dynamically to refer to "root-arm64"
instead. Takes one of "alpha", "arc", "arm", "arm64", "ia64", "loongarch64",
"mips-le", "mips64-le", "parisc", "ppc", "ppc64", "ppc64-le", "riscv32", "riscv64",
"s390", "s390x", "tilegx", "x86" or "x86-64".
Added in version 254.
--offline=BOOL
Instructs systemd-repart to build the image offline. Takes a boolean or "auto".
Defaults to "auto". If enabled, the image is built without using loop devices. This is
useful to build images unprivileged or when loop devices are not available. If
disabled, the image is always built using loop devices. If "auto", systemd-repart will
build the image online if possible and fall back to building the image offline if loop
devices are not available or cannot be accessed due to missing permissions.
Added in version 254.
--copy-from=IMAGE
Instructs systemd-repart to synthesize partition definitions from the partition table
in the given image. This option can be specified multiple times to synthesize
definitions from each of the given images. The generated definitions will copy the
partitions into the destination partition table. The copied partitions will have the
same size, metadata and contents but might have a different partition number and might
be located at a different offset in the destination partition table. These definitions
can be combined with partition definitions read from regular partition definition
files. The synthesized definitions take precedence over the definitions read from
partition definition files.
Added in version 255.
--copy-source=PATH, -s PATH
Specifies a source directory all CopyFiles= source paths shall be considered relative
to. This is similar to --root=, but exclusively applies to the CopyFiles= setting. If
--root= and --copy-source= are used in combination the former applies as usual, except
for CopyFiles= where the latter takes precedence.
Added in version 255.
--make-ddi=TYPE
Takes one of "sysext", "confext" or "portable". Generates a Discoverable Disk Image
(DDI) for a system extension (sysext, see systemd-sysext(8) for details),
configuration extension (confext) or portable service[1]. The generated image will
consist of a signed Verity "erofs" file system as root partition. In this mode of
operation the partition definitions in /usr/lib/repart.d/*.conf and related
directories are not read, and --definitions= is not supported, as appropriate
definitions for the selected DDI class will be chosen automatically.
Must be used in conjunction with --copy-source= to specify the file hierarchy to
populate the DDI with. The specified directory should contain an etc/ subdirectory if
"confext" is selected. If "sysext" is selected it should contain either a usr/ or opt/
directory, or both. If "portable" is used a full OS file hierarchy can be provided.
This option implies --empty=create, --size=auto and --seed=random (the latter two can
be overridden).
The private key and certificate for signing the DDI must be specified via the
--private-key= and --certificate= switches.
Added in version 255.
-S, -C, -P
Shortcuts for --make-ddi=sysext, --make-ddi=confext, --make-ddi=portable,
respectively.
Added in version 255.
--generate-fstab=PATH
Specifies a path where to write fstab entries for the mountpoints configured with
MountPoint= in the root directory specified with --copy-source= or --root= or in the
host's root directory if neither is specified. Disabled by default.
Added in version 256.
--generate-crypttab=PATH
Specifies a path where to write crypttab entries for the encrypted volumes configured
with EncryptedVolume= in the root directory specified with --copy-source= or --root=
or in the host's root directory if neither is specified. Disabled by default.
Added in version 256.
-h, --help
Print a short help text and exit.
--version
Print a short version string and exit.
--no-pager
Do not pipe output into a pager.
--no-legend
Do not print the legend, i.e. column headers and the footer with hints.
--json=MODE
Shows output formatted as JSON. Expects one of "short" (for the shortest possible
output without any redundant whitespace or line breaks), "pretty" (for a pretty
version of the same, with indentation and line breaks) or "off" (to turn off JSON
output, the default).
EXIT STATUS
On success, 0 is returned, and a non-zero failure code otherwise.
EXAMPLE
Example 1. Generate a configuration extension image
The following creates a configuration extension DDI (confext) for an /etc/motd update:
mkdir -p tree/etc/extension-release.d
echo "Hello World" >tree/etc/motd
cat >tree/etc/extension-release.d/extension-release.my-motd <<EOF
ID=fedora
VERSION_ID=38
IMAGE_ID=my-motd
IMAGE_VERSION=7
EOF
systemd-repart -C \
--private-key=privkey.pem \
--certificate=cert.crt \
-s tree/ \
/var/lib/confexts/my-motd.confext.raw
systemd-confext refresh
The DDI generated that way may be applied to the system with systemd-confext(1).
Example 2. Generate a system extension image and sign it via PKCS11
The following creates a system extension DDI (sysext) for an /usr/foo update and signs it
with a hardware token via PKCS11.
mkdir -p tree/usr/lib/extension-release.d
echo "Hello World" >tree/usr/foo
cat >tree/usr/lib/extension-release.d/extension-release.my-foo <<EOF
ID=fedora
VERSION_ID=38
IMAGE_ID=my-foo
IMAGE_VERSION=7
EOF
systemd-repart --make-ddi=sysext \
--private-key-source=engine:pkcs11 \
--private-key="pkcs11:model=PKCS%2315%20emulated;manufacturer=piv_II;serial=0123456789abcdef;token=Some%20Cert" \
--certificate=cert.crt \
-s tree/ \
/var/lib/extensions/my-foo.sysext.raw
systemd-sysext refresh
The DDI generated that way may be applied to the system with systemd-sysext(1).
SEE ALSO
systemd(1), repart.d(5), machine-id(5), systemd-cryptenroll(1), portablectl(1), systemd-
sysext(8)
NOTES
1. portable service
https://systemd.io/PORTABLE_SERVICES