man > systemd-repart.service(8)

SYSTEMD-REPART(8)                          systemd-repart                          SYSTEMD-REPART(8)

NAME
       systemd-repart, systemd-repart.service - Automatically grow and add partitions

SYNOPSIS


       systemd-repart [OPTIONS...] [[BLOCKDEVICE]...]

       systemd-repart.service

DESCRIPTION
       systemd-repart grows and adds partitions to a partition table, based on the configuration
       files described in repart.d(5).

       If invoked with no arguments, it operates on the block device backing the root file system
       partition of the running OS, thus growing and adding partitions of the booted OS image
       itself. If --image= is used it will operate on the specified image file. 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. 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 (mostly) operates in a purely incremental mode: it only grows
       existing and adds new partitions; it 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.

       systemd-repart is intended to be used when deploying OS images, to automatically adjust them
       to the system they are running on, during first boot. This way the deployed image can be
       minimal in size and may be augmented automatically at boot when needed, taking possession of
       disk space available but not yet used. Specifically 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 looked for
           in directories with same name as the configuration file with a suffix ".d" added.

        2. The partition table already existing on the block device is loaded and parsed.

        3. The existing partitions in the partition table are matched up 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 left-over existing
           partitions that have no matching configuration file are considered "foreign" and left as
           they are. And any configuration files for which no partition currently exists are
           understood as a request to create such 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 exception to the normally strictly incremental operation, when called in a special
       "factory reset" mode, systemd-repart may also 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 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 to operate on. Instead of a block
       device node path a regular file may be specified too, in which case the command operates on
       it like it would if a loopback block device node was specified with the file attached. 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.

       --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...]
           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= [PARTITION...], --exclude-partitions= [PARTITION...]
           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= [PARTITION...]
           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.

       -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, 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 tree tree/etc 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).

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

systemd 255                                                                        SYSTEMD-REPART(8)