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NAME | SYNOPSIS | DESCRIPTION | [FEATURE] SECTION OPTIONS | SPECIFIERS | EXAMPLES | SEE ALSO | NOTES | COLOPHON |
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SYSUPDATE.FEATURES(5) sysupdate.features SYSUPDATE.FEATURES(5)
sysupdate.features - Definition Files for Optional Features
/etc/sysupdate.d/*.feature
/run/sysupdate.d/*.feature
/usr/local/lib/sysupdate.d/*.feature
/usr/lib/sysupdate.d/*.feature
"Optional Features" are functionality provided by
systemd-sysupdate(8), that allow a distribution to define sets of
sysupdate.d(5) transfer definitions that are intended to be
enabled or disabled by the system administrator.
When a feature is enabled, transfers belonging to it will be
considered when checking for and downloading updates, when
vacuuming, and in all other situations. In effect, transfers
belonging to a feature will always be updated in lock-step with
the rest of their target. This is the primary difference an
Optional Feature and a systemd-sysupdate(8) component. When a
feature is disabled, its transfers will not be considered when
checking for and downloading updates, but systemd-sysupdate will
still consider them while vacuuming and in other situations where
it needs to determine ownership over previously downloaded system
resources. systemd-sysupdate will clean up all instances of the
feature's transfers whenever it is disabled, effectively
uninstalling it.
Optional Features are described by sysupdate.d/*.feature files,
which are defined below. Transfers can declare that they belong to
a feature via the Features= setting. Feature definitions support
drop-in files, which are most commonly used to override the
Enabled= setting. They can also be masked to hide the availability
of the feature entirely.
Each *.feature file contains one section: [Feature].
This section defines general properties of this feature.
Description=
A short human-readable description of this feature. This may
be used as a label for this feature, so the string should
meaningfully identify the feature among the features available
in sysupdate.d/.
Added in version 257.
Documentation=
A user-presentable URL to documentation about this feature.
This setting supports specifier expansion; see below for
details on supported specifiers.
Added in version 257.
AppStream=
A URL to an AppStream catalog[1] XML file. This may be used by
software centers (such as GNOME Software or KDE Discover) to
present rich metadata about this feature. This includes
display names, changelogs, icons, and more. This setting
supports specifier expansion; see below for details on
supported specifiers.
Added in version 257.
Enabled=
Whether or not this feature is enabled. If unspecified, the
feature is disabled by default.
Added in version 257.
Specifiers may be used in the Documentation= and AppStream=
settings. The following expansions are understood:
Table 1. Specifiers available
┌───────────┬──────────────────┬────────────────────────┐
│ Specifier │ Meaning │ Details │
├───────────┼──────────────────┼────────────────────────┤
│ "%a" │ Architecture │ A short string │
│ │ │ identifying the │
│ │ │ architecture of │
│ │ │ the local system. │
│ │ │ A string such as │
│ │ │ x86, x86-64 or │
│ │ │ arm64. See the │
│ │ │ architectures │
│ │ │ defined for │
│ │ │ ConditionArchitecture= │
│ │ │ in systemd.unit(5) │
│ │ │ for a full list. │
├───────────┼──────────────────┼────────────────────────┤
│ "%A" │ Operating system │ The operating system │
│ │ image version │ image version │
│ │ │ identifier of the │
│ │ │ running system, as │
│ │ │ read from the │
│ │ │ IMAGE_VERSION= field │
│ │ │ of /etc/os-release. If │
│ │ │ not set, resolves to │
│ │ │ an empty string. See │
│ │ │ os-release(5) for more │
│ │ │ information. │
├───────────┼──────────────────┼────────────────────────┤
│ "%b" │ Boot ID │ The boot ID of the │
│ │ │ running system, │
│ │ │ formatted as string. │
│ │ │ See random(4) for more │
│ │ │ information. │
├───────────┼──────────────────┼────────────────────────┤
│ "%B" │ Operating system │ The operating system │
│ │ build ID │ build identifier of │
│ │ │ the running system, as │
│ │ │ read from the │
│ │ │ BUILD_ID= field of │
│ │ │ /etc/os-release. If │
│ │ │ not set, resolves to │
│ │ │ an empty string. See │
│ │ │ os-release(5) for more │
│ │ │ information. │
├───────────┼──────────────────┼────────────────────────┤
│ "%H" │ Host name │ The hostname of the │
│ │ │ running system. │
├───────────┼──────────────────┼────────────────────────┤
│ "%l" │ Short host name │ The hostname of the │
│ │ │ running system, │
│ │ │ truncated at the first │
│ │ │ dot to remove any │
│ │ │ domain component. │
├───────────┼──────────────────┼────────────────────────┤
│ "%m" │ Machine ID │ The machine ID of the │
│ │ │ running system, │
│ │ │ formatted as string. │
│ │ │ See machine-id(5) for │
│ │ │ more information. │
├───────────┼──────────────────┼────────────────────────┤
│ "%M" │ Operating system │ The operating system │
│ │ image identifier │ image identifier of │
│ │ │ the running system, as │
│ │ │ read from the │
│ │ │ IMAGE_ID= field of │
│ │ │ /etc/os-release. If │
│ │ │ not set, resolves to │
│ │ │ an empty string. See │
│ │ │ os-release(5) for more │
│ │ │ information. │
├───────────┼──────────────────┼────────────────────────┤
│ "%o" │ Operating system │ The operating system │
│ │ ID │ identifier of the │
│ │ │ running system, as │
│ │ │ read from the ID= │
│ │ │ field of │
│ │ │ /etc/os-release. See │
│ │ │ os-release(5) for more │
│ │ │ information. │
├───────────┼──────────────────┼────────────────────────┤
│ "%v" │ Kernel release │ Identical to uname -r │
│ │ │ output. │
├───────────┼──────────────────┼────────────────────────┤
│ "%w" │ Operating system │ The operating system │
│ │ version ID │ version identifier of │
│ │ │ the running system, as │
│ │ │ read from the │
│ │ │ VERSION_ID= field of │
│ │ │ /etc/os-release. If │
│ │ │ not set, resolves to │
│ │ │ an empty string. See │
│ │ │ os-release(5) for more │
│ │ │ information. │
├───────────┼──────────────────┼────────────────────────┤
│ "%W" │ Operating system │ The operating system │
│ │ variant ID │ variant identifier of │
│ │ │ the running system, as │
│ │ │ read from the │
│ │ │ VARIANT_ID= field of │
│ │ │ /etc/os-release. If │
│ │ │ not set, resolves to │
│ │ │ an empty string. See │
│ │ │ os-release(5) for more │
│ │ │ information. │
├───────────┼──────────────────┼────────────────────────┤
│ "%T" │ Directory for │ This is either /tmp or │
│ │ temporary files │ the path "$TMPDIR", │
│ │ │ "$TEMP" or "$TMP" are │
│ │ │ set to. (Note that the │
│ │ │ directory may be │
│ │ │ specified without a │
│ │ │ trailing slash.) │
├───────────┼──────────────────┼────────────────────────┤
│ "%V" │ Directory for │ This is either │
│ │ larger and │ /var/tmp or the path │
│ │ persistent │ "$TMPDIR", "$TEMP" or │
│ │ temporary files │ "$TMP" are set to. │
│ │ │ (Note that the │
│ │ │ directory may be │
│ │ │ specified without a │
│ │ │ trailing slash.) │
├───────────┼──────────────────┼────────────────────────┤
│ "%%" │ Single percent │ Use "%%" in place of │
│ │ sign │ "%" to specify a │
│ │ │ single percent sign. │
└───────────┴──────────────────┴────────────────────────┘
Example 1. Development Tools for Image-Based OS
We'll use the hypothetical "foobarOS" described in sysupdate.d(5)
as our example base OS. The vast majority of foobarOS's users have
no need for a compiler, build system, debugger, and other such
development tools to be part of their OS. However, the developers
of foobarOS itself need this build tooling to be available. So,
foobarOS needs to provide a system extension image (see
systemd-sysext(8)) containing these development tools, and this
image must be updated in lock-step with the underlying base OS.
This is a great use case for an optional OS feature, so let's
define one:
# /usr/lib/sysupdate.d/devel.feature
[Feature]
Description=Development Tools
Documentation=https://developer.example.com/foobarOS/getting-started
Enabled=false
The above defines the "devel" feature, and disables it by default.
Now let's define a transfer that's associated with this feature:
# /usr/lib/sysupdate.d/50-devel.transfer
[Transfer]
Features=devel
ProtectVersion=%A
[Source]
Type=url-file
Path=https://download.example.com/
MatchPattern=foobarOS_@v_devel.raw.xz
[Target]
Type=regular-file
Path=/var/lib/extensions
MatchPattern=foobarOS_@v_devel.raw
Mode=0444
InstancesMax=2
With these two files, we have created a feature called "devel"
that, when enabled, will download and decompress the appropriate
version of "https://download.example.com/foobarOS_@v_devel.raw.xz"
into "/var/lib/extensions/foobarOS_@v_devel.raw" during each OS
update.
The developers of foobarOS can enable the "devel" feature on their
workstations by creating the following drop-in:
# /etc/sysupdate.d/devel.feature.d/enable.conf
[Feature]
Enabled=true
Example 2. Proprietary Drivers
Suppose that many of foobarOS's users have a GPU manufactured by
the MVISUAL corporation. Due to lack of documentation and
difficulty in reverse-engineering the hardware, the open-source
drivers for MVISUAL GPUs are unable to make proper use of
available graphics and compute performance. MVISUAL provides a
redistributable proprietary driver for their cards, and foobarOS's
developers distribute them to address their users' needs.
MVISUAL's driver has a couple different parts that must be
installed for it to function: a UKI addon to configure the kernel
command-line, an initrd system extension image to add the MVISUAL
kernel module into the initrd, and a regular system extension
image to add the proprietary OpenGL and Vulkan userspace drivers.
All of these should be version-locked to the core OS.
Let's start by defining an optional feature named
"mvisual-driver":
# /usr/lib/sysupdate.d/mvisual-driver.feature
[Feature]
Description=MVISUAL Proprietary GPU Driver
Documentation=https://support.example.com/foobarOS/mvisual
AppStream=https://metadata.example.com/mvisual-driver-%A.xml.gz
Note that we define AppStream metadata for this feature, because
we want software centers to present it to end-users. Next, let's
define the corresponding transfers:
# /usr/lib/sysupdate.d/50-mvisual-userspace.transfer
[Transfer]
Features=mvisual-driver
ProtectVersion=%A
[Source]
Type=url-file
Path=https://download.example.com/
MatchPattern=foobarOS_@v_mvisual_userspace.raw.xz
[Target]
Type=regular-file
Path=/var/lib/extensions
MatchPattern=foobarOS_@v_mvisual.raw
Mode=0444
InstancesMax=2
# /usr/lib/sysupdate.d/70-mvisual-initrd.transfer
[Transfer]
Features=mvisual-driver
ProtectVersion=%A
[Source]
Type=url-file
Path=https://download.example.com/
MatchPattern=foobarOS_@v_mvisual_initrd.raw.xz
[Target]
Type=regular-file
Path=/EFI/Linux
PathRelativeTo=boot
MatchPattern=foobarOS_@v.efi.extra.d/foobarOS_mvisual.raw
Mode=0444
InstancesMax=2
# /usr/lib/sysupdate.d/90-mvisual-addon.transfer
[Transfer]
Features=mvisual-driver
ProtectVersion=%A
[Source]
Type=url-file
Path=https://download.example.com/
MatchPattern=foobarOS_@v_mvisual_addon.efi.xz
[Target]
Type=regular-file
Path=/EFI/Linux
PathRelativeTo=boot
MatchPattern=foobarOS_@v.efi.extra.d/foobarOS_mvisual.addon.efi
Mode=0444
InstancesMax=2
Example 3. Intersecting Features
Suppose that MVISUAL releases special tooling to help a
distribution developer troubleshoot crashes in their proprietary
driver. Let's define a transfer:
# /usr/lib/sysupdate.d/50-mvisual-debugger.transfer
[Transfer]
RequisiteFeatures=devel mvisual-driver
ProtectVersion=%A
[Source]
Type=url-file
Path=https://download.example.com/
MatchPattern=foobarOS_@v_devel.raw.xz
[Target]
Type=regular-file
Path=/var/lib/extensions
MatchPattern=foobarOS_@v_devel.raw
Mode=0444
InstancesMax=2
This transfer will be used only if both the "devel" and
"mvisual-driver" features are enabled.
systemd(1), systemd-sysupdate(8), sysupdate.d(5)
1. AppStream catalog
https://www.freedesktop.org/software/appstream/docs/chap-CatalogData.html
This page is part of the systemd (systemd system and service
manager) project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have a
bug report for this manual page, see
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.
This page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2025-08-11. (At that
time, the date of the most recent commit that was found in the
repository was 2025-08-11.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
systemd 258~rc2 SYSUPDATE.FEATURES(5)
Pages that refer to this page: updatectl(1), sysupdate.d(5), systemd.directives(7), systemd.index(7)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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