Provided by: systemd-container_257.4-1ubuntu3.2_amd64 
NAME
sysupdate.features - Definition Files for Optional Features
SYNOPSIS
/etc/sysupdate.d/*.feature
/run/sysupdate.d/*.feature
/usr/local/lib/sysupdate.d/*.feature
/usr/lib/sysupdate.d/*.feature
DESCRIPTION
"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 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 out to
hide the availability of the feature entirely.
Each *.feature file contains one section: [Feature].
[FEATURE] SECTION OPTIONS
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,
chagnelogs, 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
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 image │ The operating system image │
│ │ version │ 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 build ID │ The operating system 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 image │ The operating system image │
│ │ identifier │ 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 ID │ The operating system │
│ │ │ 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 version ID │ The operating system 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 variant ID │ The operating system 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 temporary │ This is either /tmp or the │
│ │ files │ path "$TMPDIR", "$TEMP" or │
│ │ │ "$TMP" are set to. (Note │
│ │ │ that the directory may be │
│ │ │ specified without a trailing │
│ │ │ slash.) │
├───────────┼─────────────────────────────┼──────────────────────────────┤
│ "%V" │ Directory for larger and │ This is either /var/tmp or │
│ │ persistent temporary files │ the path "$TMPDIR", "$TEMP" │
│ │ │ or "$TMP" are set to. (Note │
│ │ │ that the directory may be │
│ │ │ specified without a trailing │
│ │ │ slash.) │
├───────────┼─────────────────────────────┼──────────────────────────────┤
│ "%%" │ Single percent sign │ Use "%%" in place of "%" to │
│ │ │ specify a single percent │
│ │ │ sign. │
└───────────┴─────────────────────────────┴──────────────────────────────┘
EXAMPLES
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 a 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.
SEE ALSO
systemd(1), systemd-sysupdate(8), sysupdate.d(5)
NOTES
1. AppStream catalog
https://www.freedesktop.org/software/appstream/docs/chap-CatalogData.html
systemd 257.4 SYSUPDATE.FEATURES(5)