systemd-sysupdate, systemd-sysupdate.service, systemd-sysupdate.timer, systemd-sysupdate-reboot.service, systemd-sysupdate-reboot.timer — Automatically Update OS or Other Resources
systemd-sysupdate atomically updates the host OS, container images, portable service images or other sources, based on the transfer configuration files described in sysupdate.d(5).
This tool implements file, directory, or partition based update schemes, supporting multiple parallel installed versions of specific resources in an A/B (or even: A/B/C, A/B/C/D/, …) style. A/B updating means that when one version of a resource is currently being used, the next version can be downloaded, unpacked, and prepared in an entirely separate location, independently of the first, and — once complete — be activated, swapping the roles so that it becomes the used one and the previously used one becomes the one that is replaced by the next update, and so on. The resources to update are defined in transfer files, one for each resource to be updated. For example, resources that may be updated with this tool could be: a root file system partition, a matching Verity partition plus one kernel image. The combination of the three would be considered a complete OS update.
The tool updates partitions, files or directory trees always in whole, and operates with at least two versions of each of these resources: the current version, plus the next version: the one that is being updated to, and which is initially incomplete as the downloaded data is written to it; plus optionally more versions. Once the download of a newer version is complete it becomes the current version, releasing the version previously considered current for deletion/replacement/updating.
When installing new versions the tool will directly download, decompress, unpack and write the new version into the destination. This is done in a robust fashion so that an incomplete download can be recognized on next invocation, and flushed out before a new attempt is initiated.
Note that when writing updates to a partition, the partition has to exist already, as systemd-sysupdate will not automatically create new partitions. Use a tool such as systemd-repart(8) to automatically create additional partitions to be used with systemd-sysupdate on boot.
The tool can both be used on the running OS, to update the OS in "online" state from within itself,
and on "offline" disk images, to update them from the outside based on transfer files
embedded in the disk images. For the latter, see
--image= below. The latter is
particularly interesting to update container images or portable service images.
systemd-sysupdate.service system service will automatically update the
host OS based on the installed transfer files. It is triggered in regular intervals via
will automatically reboot the system after a new version is installed. It is triggered via
systemd-sysupdate-reboot.timer. The two services are separate from each other as it
is typically advisable to download updates regularly while the system is up, but delay reboots until the
appropriate time (i.e. typically at night). The two sets of service/timer units may be enabled
For details about transfer files and examples see sysupdate.d(5).
The following commands are understood:
If invoked without an argument, enumerates downloadable and installed versions, and shows a summarizing table with the discovered versions and their properties, including whether there's a newer candidate version to update to. If a version argument is specified, shows details about the specific version, including the individual files that need to be transferred to acquire the version.
If no command is explicitly specified this command is implied.
Checks if there's a new version available. This internally enumerates downloadable and installed versions and returns exit status 0 if there's a new version to update to, non-zero otherwise. If there is a new version to update to, its version identifier is written to standard output.
Installs (updates to) the specified version, or if none is specified to the newest version available. If the version is already installed or no newer version available, no operation is executed.
If a new version to install/update to is found, old installed versions are deleted until at
least one new version can be installed, as configured via
via the available partition slots of the right type. This implicit operation can also be invoked
explicitly via the vacuum command described below.
Deletes old installed versions until the limits configured via
met again. Normally, it should not be necessary to invoke this command explicitly, since it is
implicitly invoked whenever a new update is initiated.
Checks whether a newer version of the OS is installed than the one currently
running. Returns zero if so, non-zero otherwise. This compares the newest installed version's
identifier with the OS image version as reported by the
IMAGE_VERSION= field in
/etc/os-release. If the former is newer than the latter, an update was
apparently completed but not activated (i.e. rebooted into) yet.
Similar to the
pending command but immediately reboots in case a
newer version of the OS has been installed than the one currently running. This operation can be done
implicitly together with the update command, after a completed update via the
--reboot switch, see below. This command will execute no operation (and return
success) if no update has been installed, and thus the system was not rebooted.
Lists components that can be updated. This enumerates the
/usr/lib/sysupdate.*.d/ directories that contain transfer files. This command is
useful to list possible parameters for
--component= (see below).
The following options are understood:
Selects the component to update. Takes a component name as argument. This has the
effect of slightly altering the search logic for transfer files. If this switch is not used, the
transfer files are loaded from
this switch is used, the specified component name is used to alter the directories to look in to be
/usr/lib/sysupdate., each time with
string replaced with the specified
Use the components command to list available components to update. This enumerates the directories matching this naming rule.
Components may be used to define a separate set of transfer files for different components of
the OS that shall be updated separately. Do not use this concept for resources that shall always be
updated together in a synchronous fashion. Simply define multiple transfer files within the same
sysupdate.d/ directory for these cases.
This option may not be combined with
A path to a directory. If specified, the transfer
are read from this directory instead of
This option may not be combined with
Takes a path to a directory to use as root file system when searching for
Takes a path to a disk image file or device to mount and use in a similar fashion to
--root=, see above. If this is used and partition resources are updated this is done
inside the specified disk image.
Takes an image policy string as argument, as per
policy is enforced when operating on the disk image specified via
above. If not specified defaults to the "
*" policy, i.e. all recognized file systems
in the image are used.
Takes a decimal integer greater than or equal to 2. Controls how many versions to
keep at any time. This option may also be configured inside the transfer files, via the
InstancesMax= setting, see
Takes a boolean argument, defaults to yes. This may be used to specify whether the newly updated resource versions shall be synchronized to disk when appropriate (i.e. after the download is complete, before it is finalized, and again after finalization). This should not be turned off, except to improve runtime performance in testing environments.
Takes a boolean argument, defaults to yes. Controls whether to cryptographically verify downloads. Do not turn this off, except in testing environments.
When used in combination with the update command and a new version is installed, automatically reboots the system immediately afterwards.
Do not pipe output into a pager.
Do not print the legend, i.e. column headers and the footer with hints.
Shows output formatted as JSON. Expects one of "
short" (for the
shortest possible output without any redundant whitespace or line breaks), "
(for a pretty version of the same, with indentation and line breaks) or "
off" (to turn
off JSON output, the default).
On success, 0 is returned, a non-zero failure code otherwise.