конфигурация агрегата (Unit configuration)
[UNIT] SECTION OPTIONS
The unit file may include a [Unit] section, which carries generic
information about the unit that is not dependent on the type of
unit:
Description=
A short human readable title of the unit. This may be used by
systemd (and other UIs) as a user-visible label for the unit,
so this string should identify the unit rather than describe
it, despite the name. This string also shouldn't just repeat
the unit name. "Apache2 Web Server" is a good example. Bad
examples are "high-performance light-weight HTTP server" (too
generic) or "Apache2" (meaningless for people who do not know
Apache, duplicates the unit name). systemd may use this
string as a noun in status messages ("Starting
description...", "Started description.", "Reached target
description.", "Failed to start description."), so it should
be capitalized, and should not be a full sentence, or a
phrase with a continuous verb. Bad examples include "exiting
the container" or "updating the database once per day.".
Documentation=
A space-separated list of URIs referencing documentation for
this unit or its configuration. Accepted are only URIs of the
types "http://", "https://", "file:", "info:", "man:". For
more information about the syntax of these URIs, see uri(7).
The URIs should be listed in order of relevance, starting
with the most relevant. It is a good idea to first reference
documentation that explains what the unit's purpose is,
followed by how it is configured, followed by any other
related documentation. This option may be specified more than
once, in which case the specified list of URIs is merged. If
the empty string is assigned to this option, the list is
reset and all prior assignments will have no effect.
Wants=
Configures (weak) requirement dependencies on other units.
This option may be specified more than once or multiple
space-separated units may be specified in one option in which
case dependencies for all listed names will be created.
Dependencies of this type may also be configured outside of
the unit configuration file by adding a symlink to a .wants/
directory accompanying the unit file. For details, see above.
Units listed in this option will be started if the
configuring unit is. However, if the listed units fail to
start or cannot be added to the transaction, this has no
impact on the validity of the transaction as a whole, and
this unit will still be started. This is the recommended way
to hook the start-up of one unit to the start-up of another
unit.
Note that requirement dependencies do not influence the order
in which services are started or stopped. This has to be
configured independently with the After= or Before= options.
If unit foo.service pulls in unit bar.service as configured
with Wants= and no ordering is configured with After= or
Before=, then both units will be started simultaneously and
without any delay between them if foo.service is activated.
Requires=
Similar to Wants=, but declares a stronger requirement
dependency. Dependencies of this type may also be configured
by adding a symlink to a .requires/ directory accompanying
the unit file.
If this unit gets activated, the units listed will be
activated as well. If one of the other units fails to
activate, and an ordering dependency After= on the failing
unit is set, this unit will not be started. Besides, with or
without specifying After=, this unit will be stopped if one
of the other units is explicitly stopped.
Often, it is a better choice to use Wants= instead of
Requires= in order to achieve a system that is more robust
when dealing with failing services.
Note that this dependency type does not imply that the other
unit always has to be in active state when this unit is
running. Specifically: failing condition checks (such as
ConditionPathExists=, ConditionPathIsSymbolicLink=, ... — see
below) do not cause the start job of a unit with a Requires=
dependency on it to fail. Also, some unit types may
deactivate on their own (for example, a service process may
decide to exit cleanly, or a device may be unplugged by the
user), which is not propagated to units having a Requires=
dependency. Use the BindsTo= dependency type together with
After= to ensure that a unit may never be in active state
without a specific other unit also in active state (see
below).
Requisite=
Similar to Requires=. However, if the units listed here are
not started already, they will not be started and the
starting of this unit will fail immediately. Requisite= does
not imply an ordering dependency, even if both units are
started in the same transaction. Hence this setting should
usually be combined with After=, to ensure this unit is not
started before the other unit.
When Requisite=b.service is used on a.service, this
dependency will show as RequisiteOf=a.service in property
listing of b.service. RequisiteOf= dependency cannot be
specified directly.
BindsTo=
Configures requirement dependencies, very similar in style to
Requires=. However, this dependency type is stronger: in
addition to the effect of Requires= it declares that if the
unit bound to is stopped, this unit will be stopped too. This
means a unit bound to another unit that suddenly enters
inactive state will be stopped too. Units can suddenly,
unexpectedly enter inactive state for different reasons: the
main process of a service unit might terminate on its own
choice, the backing device of a device unit might be
unplugged or the mount point of a mount unit might be
unmounted without involvement of the system and service
manager.
When used in conjunction with After= on the same unit the
behaviour of BindsTo= is even stronger. In this case, the
unit bound to strictly has to be in active state for this
unit to also be in active state. This not only means a unit
bound to another unit that suddenly enters inactive state,
but also one that is bound to another unit that gets skipped
due to a failed condition check (such as
ConditionPathExists=, ConditionPathIsSymbolicLink=, ... — see
below) will be stopped, should it be running. Hence, in many
cases it is best to combine BindsTo= with After=.
When BindsTo=b.service is used on a.service, this dependency
will show as BoundBy=a.service in property listing of
b.service. BoundBy= dependency cannot be specified directly.
PartOf=
Configures dependencies similar to Requires=, but limited to
stopping and restarting of units. When systemd stops or
restarts the units listed here, the action is propagated to
this unit. Note that this is a one-way dependency — changes
to this unit do not affect the listed units.
When PartOf=b.service is used on a.service, this dependency
will show as ConsistsOf=a.service in property listing of
b.service. ConsistsOf= dependency cannot be specified
directly.
Upholds=
Configures dependencies similar to Wants=, but as long as
this unit is up, all units listed in Upholds= are started
whenever found to be inactive or failed, and no job is queued
for them. While a Wants= dependency on another unit has a
one-time effect when this units started, a Upholds=
dependency on it has a continuous effect, constantly
restarting the unit if necessary. This is an alternative to
the Restart= setting of service units, to ensure they are
kept running whatever happens.
When Upholds=b.service is used on a.service, this dependency
will show as UpheldBy=a.service in the property listing of
b.service. The UpheldBy= dependency cannot be specified
directly.
Conflicts=
A space-separated list of unit names. Configures negative
requirement dependencies. If a unit has a Conflicts= setting
on another unit, starting the former will stop the latter and
vice versa.
Note that this setting does not imply an ordering dependency,
similarly to the Wants= and Requires= dependencies described
above. This means that to ensure that the conflicting unit is
stopped before the other unit is started, an After= or
Before= dependency must be declared. It doesn't matter which
of the two ordering dependencies is used, because stop jobs
are always ordered before start jobs, see the discussion in
Before=/After= below.
If unit A that conflicts with unit B is scheduled to be
started at the same time as B, the transaction will either
fail (in case both are required parts of the transaction) or
be modified to be fixed (in case one or both jobs are not a
required part of the transaction). In the latter case, the
job that is not required will be removed, or in case both are
not required, the unit that conflicts will be started and the
unit that is conflicted is stopped.
Before=, After=
These two settings expect a space-separated list of unit
names. They may be specified more than once, in which case
dependencies for all listed names are created.
Those two settings configure ordering dependencies between
units. If unit foo.service contains the setting
Before=bar.service and both units are being started,
bar.service's start-up is delayed until foo.service has
finished starting up. After= is the inverse of Before=, i.e.
while Before= ensures that the configured unit is started
before the listed unit begins starting up, After= ensures the
opposite, that the listed unit is fully started up before the
configured unit is started.
When two units with an ordering dependency between them are
shut down, the inverse of the start-up order is applied. I.e.
if a unit is configured with After= on another unit, the
former is stopped before the latter if both are shut down.
Given two units with any ordering dependency between them, if
one unit is shut down and the other is started up, the
shutdown is ordered before the start-up. It doesn't matter if
the ordering dependency is After= or Before=, in this case.
It also doesn't matter which of the two is shut down, as long
as one is shut down and the other is started up; the shutdown
is ordered before the start-up in all cases. If two units
have no ordering dependencies between them, they are shut
down or started up simultaneously, and no ordering takes
place. It depends on the unit type when precisely a unit has
finished starting up. Most importantly, for service units
start-up is considered completed for the purpose of
Before=/After= when all its configured start-up commands have
been invoked and they either failed or reported start-up
success. Note that this does includes ExecStartPost= (or
ExecStopPost= for the shutdown case).
Note that those settings are independent of and orthogonal to
the requirement dependencies as configured by Requires=,
Wants=, Requisite=, or BindsTo=. It is a common pattern to
include a unit name in both the After= and Wants= options, in
which case the unit listed will be started before the unit
that is configured with these options.
Note that Before= dependencies on device units have no effect
and are not supported. Devices generally become available as
a result of an external hotplug event, and systemd creates
the corresponding device unit without delay.
OnFailure=
A space-separated list of one or more units that are
activated when this unit enters the "failed" state. A service
unit using Restart= enters the failed state only after the
start limits are reached.
OnSuccess=
A space-separated list of one or more units that are
activated when this unit enters the "inactive" state.
PropagatesReloadTo=, ReloadPropagatedFrom=
A space-separated list of one or more units to which reload
requests from this unit shall be propagated to, or units from
which reload requests shall be propagated to this unit,
respectively. Issuing a reload request on a unit will
automatically also enqueue reload requests on all units that
are linked to it using these two settings.
PropagatesStopTo=, StopPropagatedFrom=
A space-separated list of one or more units to which stop
requests from this unit shall be propagated to, or units from
which stop requests shall be propagated to this unit,
respectively. Issuing a stop request on a unit will
automatically also enqueue stop requests on all units that
are linked to it using these two settings.
JoinsNamespaceOf=
For units that start processes (such as service units), lists
one or more other units whose network and/or temporary file
namespace to join. This only applies to unit types which
support the PrivateNetwork=, NetworkNamespacePath=,
PrivateIPC=, IPCNamespacePath=, and PrivateTmp= directives
(see systemd.exec(5) for details). If a unit that has this
setting set is started, its processes will see the same
/tmp/, /var/tmp/, IPC namespace and network namespace as one
listed unit that is started. If multiple listed units are
already started, it is not defined which namespace is joined.
Note that this setting only has an effect if
PrivateNetwork=/NetworkNamespacePath=,
PrivateIPC=/IPCNamespacePath= and/or PrivateTmp= is enabled
for both the unit that joins the namespace and the unit whose
namespace is joined.
RequiresMountsFor=
Takes a space-separated list of absolute paths. Automatically
adds dependencies of type Requires= and After= for all mount
units required to access the specified path.
Mount points marked with noauto are not mounted automatically
through local-fs.target, but are still honored for the
purposes of this option, i.e. they will be pulled in by this
unit.
OnFailureJobMode=
Takes a value of "fail", "replace", "replace-irreversibly",
"isolate", "flush", "ignore-dependencies" or
"ignore-requirements". Defaults to "replace". Specifies how
the units listed in OnFailure= will be enqueued. See
systemctl(1)'s --job-mode= option for details on the possible
values. If this is set to "isolate", only a single unit may
be listed in OnFailure=.
IgnoreOnIsolate=
Takes a boolean argument. If true, this unit will not be
stopped when isolating another unit. Defaults to false for
service, target, socket, timer, and path units, and true for
slice, scope, device, swap, mount, and automount units.
StopWhenUnneeded=
Takes a boolean argument. If true, this unit will be stopped
when it is no longer used. Note that, in order to minimize
the work to be executed, systemd will not stop units by
default unless they are conflicting with other units, or the
user explicitly requested their shut down. If this option is
set, a unit will be automatically cleaned up if no other
active unit requires it. Defaults to false.
RefuseManualStart=, RefuseManualStop=
Takes a boolean argument. If true, this unit can only be
activated or deactivated indirectly. In this case, explicit
start-up or termination requested by the user is denied,
however if it is started or stopped as a dependency of
another unit, start-up or termination will succeed. This is
mostly a safety feature to ensure that the user does not
accidentally activate units that are not intended to be
activated explicitly, and not accidentally deactivate units
that are not intended to be deactivated. These options
default to false.
AllowIsolate=
Takes a boolean argument. If true, this unit may be used with
the systemctl isolate command. Otherwise, this will be
refused. It probably is a good idea to leave this disabled
except for target units that shall be used similar to
runlevels in SysV init systems, just as a precaution to avoid
unusable system states. This option defaults to false.
DefaultDependencies=
Takes a boolean argument. If yes, (the default), a few
default dependencies will implicitly be created for the unit.
The actual dependencies created depend on the unit type. For
example, for service units, these dependencies ensure that
the service is started only after basic system initialization
is completed and is properly terminated on system shutdown.
See the respective man pages for details. Generally, only
services involved with early boot or late shutdown should set
this option to no. It is highly recommended to leave this
option enabled for the majority of common units. If set to
no, this option does not disable all implicit dependencies,
just non-essential ones.
CollectMode=
Tweaks the "garbage collection" algorithm for this unit.
Takes one of inactive or inactive-or-failed. If set to
inactive the unit will be unloaded if it is in the inactive
state and is not referenced by clients, jobs or other units —
however it is not unloaded if it is in the failed state. In
failed mode, failed units are not unloaded until the user
invoked systemctl reset-failed on them to reset the failed
state, or an equivalent command. This behaviour is altered if
this option is set to inactive-or-failed: in this case the
unit is unloaded even if the unit is in a failed state, and
thus an explicitly resetting of the failed state is not
necessary. Note that if this mode is used unit results (such
as exit codes, exit signals, consumed resources, ...) are
flushed out immediately after the unit completed, except for
what is stored in the logging subsystem. Defaults to
inactive.
FailureAction=, SuccessAction=
Configure the action to take when the unit stops and enters a
failed state or inactive state. Takes one of none, reboot,
reboot-force, reboot-immediate, poweroff, poweroff-force,
poweroff-immediate, exit, and exit-force. In system mode, all
options are allowed. In user mode, only none, exit, and
exit-force are allowed. Both options default to none.
If none is set, no action will be triggered. reboot causes a
reboot following the normal shutdown procedure (i.e.
equivalent to systemctl reboot). reboot-force causes a
forced reboot which will terminate all processes forcibly but
should cause no dirty file systems on reboot (i.e. equivalent
to systemctl reboot -f) and reboot-immediate causes immediate
execution of the reboot(2) system call, which might result in
data loss (i.e. equivalent to systemctl reboot -ff).
Similarly, poweroff, poweroff-force, poweroff-immediate have
the effect of powering down the system with similar
semantics. exit causes the manager to exit following the
normal shutdown procedure, and exit-force causes it terminate
without shutting down services. When exit or exit-force is
used by default the exit status of the main process of the
unit (if this applies) is returned from the service manager.
However, this may be overridden with
FailureActionExitStatus=/SuccessActionExitStatus=, see below.
FailureActionExitStatus=, SuccessActionExitStatus=
Controls the exit status to propagate back to an invoking
container manager (in case of a system service) or service
manager (in case of a user manager) when the
FailureAction=/SuccessAction= are set to exit or exit-force
and the action is triggered. By default the exit status of
the main process of the triggering unit (if this applies) is
propagated. Takes a value in the range 0...255 or the empty
string to request default behaviour.
JobTimeoutSec=, JobRunningTimeoutSec=
JobTimeoutSec= specifies a timeout for the whole job that
starts running when the job is queued. JobRunningTimeoutSec=
specifies a timeout that starts running when the queued job
is actually started. If either limit is reached, the job will
be cancelled, the unit however will not change state or even
enter the "failed" mode.
Both settings take a time span with the default unit of
seconds, but other units may be specified, see
systemd.time(5). The default is "infinity" (job timeouts
disabled), except for device units where
JobRunningTimeoutSec= defaults to DefaultTimeoutStartSec=.
Note: these timeouts are independent from any unit-specific
timeouts (for example, the timeout set with TimeoutStartSec=
in service units). The job timeout has no effect on the unit
itself. Or in other words: unit-specific timeouts are useful
to abort unit state changes, and revert them. The job timeout
set with this option however is useful to abort only the job
waiting for the unit state to change.
JobTimeoutAction=, JobTimeoutRebootArgument=
JobTimeoutAction= optionally configures an additional action
to take when the timeout is hit, see description of
JobTimeoutSec= and JobRunningTimeoutSec= above. It takes the
same values as StartLimitAction=. Defaults to none.
JobTimeoutRebootArgument= configures an optional reboot
string to pass to the reboot(2) system call.
StartLimitIntervalSec=interval, StartLimitBurst=burst
Configure unit start rate limiting. Units which are started
more than burst times within an interval time span are not
permitted to start any more. Use StartLimitIntervalSec= to
configure the checking interval and StartLimitBurst= to
configure how many starts per interval are allowed.
interval is a time span with the default unit of seconds, but
other units may be specified, see systemd.time(5). Defaults
to DefaultStartLimitIntervalSec= in manager configuration
file, and may be set to 0 to disable any kind of rate
limiting. burst is a number and defaults to
DefaultStartLimitBurst= in manager configuration file.
These configuration options are particularly useful in
conjunction with the service setting Restart= (see
systemd.service(5)); however, they apply to all kinds of
starts (including manual), not just those triggered by the
Restart= logic.
Note that units which are configured for Restart=, and which
reach the start limit are not attempted to be restarted
anymore; however, they may still be restarted manually or
from a timer or socket at a later point, after the interval
has passed. From that point on, the restart logic is
activated again. systemctl reset-failed will cause the
restart rate counter for a service to be flushed, which is
useful if the administrator wants to manually start a unit
and the start limit interferes with that. Rate-limiting is
enforced after any unit condition checks are executed, and
hence unit activations with failing conditions do not count
towards the rate limit.
When a unit is unloaded due to the garbage collection logic
(see above) its rate limit counters are flushed out too. This
means that configuring start rate limiting for a unit that is
not referenced continuously has no effect.
This setting does not apply to slice, target, device, and
scope units, since they are unit types whose activation may
either never fail, or may succeed only a single time.
StartLimitAction=
Configure an additional action to take if the rate limit
configured with StartLimitIntervalSec= and StartLimitBurst=
is hit. Takes the same values as the
FailureAction=/SuccessAction= settings. If none is set,
hitting the rate limit will trigger no action except that the
start will not be permitted. Defaults to none.
RebootArgument=
Configure the optional argument for the reboot(2) system call
if StartLimitAction= or FailureAction= is a reboot action.
This works just like the optional argument to systemctl
reboot command.
SourcePath=
A path to a configuration file this unit has been generated
from. This is primarily useful for implementation of
generator tools that convert configuration from an external
configuration file format into native unit files. This
functionality should not be used in normal units.
Conditions and Asserts
Unit files may also include a number of Condition...= and
Assert...= settings. Before the unit is started, systemd will
verify that the specified conditions and asserts are true. If
not, the starting of the unit will be (mostly silently) skipped
(in case of conditions), or aborted with an error message (in
case of asserts). Failing conditions or asserts will not result
in the unit being moved into the "failed" state. The conditions
and asserts are checked at the time the queued start job is to be
executed. The ordering dependencies are still respected, so other
units are still pulled in and ordered as if this unit was
successfully activated, and the conditions and asserts are
executed the precise moment the unit would normally start and
thus can validate system state after the units ordered before
completed initialization. Use condition expressions for skipping
units that do not apply to the local system, for example because
the kernel or runtime environment doesn't require their
functionality.
If multiple conditions are specified, the unit will be executed
if all of them apply (i.e. a logical AND is applied). Condition
checks can use a pipe symbol ("|") after the equals sign
("Condition...=|..."), which causes the condition to become a
triggering condition. If at least one triggering condition is
defined for a unit, then the unit will be started if at least one
of the triggering conditions of the unit applies and all of the
regular (i.e. non-triggering) conditions apply. If you prefix an
argument with the pipe symbol and an exclamation mark, the pipe
symbol must be passed first, the exclamation second. If any of
these options is assigned the empty string, the list of
conditions is reset completely, all previous condition settings
(of any kind) will have no effect.
The AssertArchitecture=, AssertVirtualization=, ... options are
similar to conditions but cause the start job to fail (instead of
being skipped). The failed check is logged. Units with failed
conditions are considered to be in a clean state and will be
garbage collected if they are not referenced. This means that
when queried, the condition failure may or may not show up in the
state of the unit.
Note that neither assertion nor condition expressions result in
unit state changes. Also note that both are checked at the time
the job is to be executed, i.e. long after depending jobs and it
itself were queued. Thus, neither condition nor assertion
expressions are suitable for conditionalizing unit dependencies.
The condition verb of systemd-analyze(1) can be used to test
condition and assert expressions.
Except for ConditionPathIsSymbolicLink=, all path checks follow
symlinks.
ConditionArchitecture=
Check whether the system is running on a specific
architecture. Takes one of "x86", "x86-64", "ppc", "ppc-le",
"ppc64", "ppc64-le", "ia64", "parisc", "parisc64", "s390",
"s390x", "sparc", "sparc64", "mips", "mips-le", "mips64",
"mips64-le", "alpha", "arm", "arm-be", "arm64", "arm64-be",
"sh", "sh64", "m68k", "tilegx", "cris", "arc", "arc-be", or
"native".
The architecture is determined from the information returned
by uname(2) and is thus subject to personality(2). Note that
a Personality= setting in the same unit file has no effect on
this condition. A special architecture name "native" is
mapped to the architecture the system manager itself is
compiled for. The test may be negated by prepending an
exclamation mark.
ConditionFirmware=
Check whether the system's firmware is of a certain type.
Possible values are: "uefi" (for systems with EFI),
"device-tree" (for systems with a device tree) and
"device-tree-compatible(xyz)" (for systems with a device tree
that is compatible to "xyz").
ConditionVirtualization=
Check whether the system is executed in a virtualized
environment and optionally test whether it is a specific
implementation. Takes either boolean value to check if being
executed in any virtualized environment, or one of "vm" and
"container" to test against a generic type of virtualization
solution, or one of "qemu", "kvm", "amazon", "zvm", "vmware",
"microsoft", "oracle", "powervm", "xen", "bochs", "uml",
"bhyve", "qnx", "openvz", "lxc", "lxc-libvirt",
"systemd-nspawn", "docker", "podman", "rkt", "wsl", "proot",
"pouch", "acrn" to test against a specific implementation, or
"private-users" to check whether we are running in a user
namespace. See systemd-detect-virt(1) for a full list of
known virtualization technologies and their identifiers. If
multiple virtualization technologies are nested, only the
innermost is considered. The test may be negated by
prepending an exclamation mark.
ConditionHost=
ConditionHost= may be used to match against the hostname or
machine ID of the host. This either takes a hostname string
(optionally with shell style globs) which is tested against
the locally set hostname as returned by gethostname(2), or a
machine ID formatted as string (see machine-id(5)). The test
may be negated by prepending an exclamation mark.
ConditionKernelCommandLine=
ConditionKernelCommandLine= may be used to check whether a
specific kernel command line option is set (or if prefixed
with the exclamation mark — unset). The argument must either
be a single word, or an assignment (i.e. two words, separated
by "="). In the former case the kernel command line is
searched for the word appearing as is, or as left hand side
of an assignment. In the latter case, the exact assignment is
looked for with right and left hand side matching. This
operates on the kernel command line communicated to userspace
via /proc/cmdline, except when the service manager is invoked
as payload of a container manager, in which case the command
line of PID 1 is used instead (i.e. /proc/1/cmdline).
ConditionKernelVersion=
ConditionKernelVersion= may be used to check whether the
kernel version (as reported by uname -r) matches a certain
expression (or if prefixed with the exclamation mark does not
match it). The argument must be a list of (potentially
quoted) expressions. For each of the expressions, if it
starts with one of "<", "<=", "=", "!=", ">=", ">" a relative
version comparison is done, otherwise the specified string is
matched with shell-style globs.
Note that using the kernel version string is an unreliable
way to determine which features are supported by a kernel,
because of the widespread practice of backporting drivers,
features, and fixes from newer upstream kernels into older
versions provided by distributions. Hence, this check is
inherently unportable and should not be used for units which
may be used on different distributions.
ConditionEnvironment=
ConditionEnvironment= may be used to check whether a specific
environment variable is set (or if prefixed with the
exclamation mark — unset) in the service manager's
environment block. The argument may be a single word, to
check if the variable with this name is defined in the
environment block, or an assignment ("name=value"), to check
if the variable with this exact value is defined. Note that
the environment block of the service manager itself is
checked, i.e. not any variables defined with Environment= or
EnvironmentFile=, as described above. This is particularly
useful when the service manager runs inside a containerized
environment or as per-user service manager, in order to check
for variables passed in by the enclosing container manager or
PAM.
ConditionSecurity=
ConditionSecurity= may be used to check whether the given
security technology is enabled on the system. Currently, the
recognized values are "selinux", "apparmor", "tomoyo", "ima",
"smack", "audit", "uefi-secureboot" and "tpm2". The test may
be negated by prepending an exclamation mark.
ConditionCapability=
Check whether the given capability exists in the capability
bounding set of the service manager (i.e. this does not check
whether capability is actually available in the permitted or
effective sets, see capabilities(7) for details). Pass a
capability name such as "CAP_MKNOD", possibly prefixed with
an exclamation mark to negate the check.
ConditionACPower=
Check whether the system has AC power, or is exclusively
battery powered at the time of activation of the unit. This
takes a boolean argument. If set to "true", the condition
will hold only if at least one AC connector of the system is
connected to a power source, or if no AC connectors are
known. Conversely, if set to "false", the condition will hold
only if there is at least one AC connector known and all AC
connectors are disconnected from a power source.
ConditionNeedsUpdate=
Takes one of /var/ or /etc/ as argument, possibly prefixed
with a "!" (to invert the condition). This condition may be
used to conditionalize units on whether the specified
directory requires an update because /usr/'s modification
time is newer than the stamp file .updated in the specified
directory. This is useful to implement offline updates of the
vendor operating system resources in /usr/ that require
updating of /etc/ or /var/ on the next following boot. Units
making use of this condition should order themselves before
systemd-update-done.service(8), to make sure they run before
the stamp file's modification time gets reset indicating a
completed update.
If the systemd.condition-needs-update= option is specified on
the kernel command line (taking a boolean), it will override
the result of this condition check, taking precedence over
any file modification time checks. If the kernel command line
option is used, systemd-update-done.service will not have
immediate effect on any following ConditionNeedsUpdate=
checks, until the system is rebooted where the kernel command
line option is not specified anymore.
Note that to make this scheme effective, the timestamp of
/usr/ should be explicitly updated after its contents are
modified. The kernel will automatically update modification
timestamp on a directory only when immediate children of a
directory are modified; an modification of nested files will
not automatically result in mtime of /usr/ being updated.
Also note that if the update method includes a call to
execute appropriate post-update steps itself, it should not
touch the timestamp of /usr/. In a typical distribution
packaging scheme, packages will do any required update steps
as part of the installation or upgrade, to make package
contents immediately usable. ConditionNeedsUpdate= should be
used with other update mechanisms where such an immediate
update does not happen.
ConditionFirstBoot=
Takes a boolean argument. This condition may be used to
conditionalize units on whether the system is booting up for
the first time. This roughly means that /etc/ is unpopulated
(for details, see "First Boot Semantics" in machine-id(5)).
This may be used to populate /etc/ on the first boot after
factory reset, or when a new system instance boots up for the
first time.
For robustness, units with ConditionFirstBoot=yes should
order themselves before first-boot-complete.target and pull
in this passive target with Wants=. This ensures that in a
case of an aborted first boot, these units will be re-run
during the next system startup.
If the systemd.condition-first-boot= option is specified on
the kernel command line (taking a boolean), it will override
the result of this condition check, taking precedence over
/etc/machine-id existence checks.
ConditionPathExists=
Check for the existence of a file. If the specified absolute
path name does not exist, the condition will fail. If the
absolute path name passed to ConditionPathExists= is prefixed
with an exclamation mark ("!"), the test is negated, and the
unit is only started if the path does not exist.
ConditionPathExistsGlob=
ConditionPathExistsGlob= is similar to ConditionPathExists=,
but checks for the existence of at least one file or
directory matching the specified globbing pattern.
ConditionPathIsDirectory=
ConditionPathIsDirectory= is similar to ConditionPathExists=
but verifies that a certain path exists and is a directory.
ConditionPathIsSymbolicLink=
ConditionPathIsSymbolicLink= is similar to
ConditionPathExists= but verifies that a certain path exists
and is a symbolic link.
ConditionPathIsMountPoint=
ConditionPathIsMountPoint= is similar to ConditionPathExists=
but verifies that a certain path exists and is a mount point.
ConditionPathIsReadWrite=
ConditionPathIsReadWrite= is similar to ConditionPathExists=
but verifies that the underlying file system is readable and
writable (i.e. not mounted read-only).
ConditionPathIsEncrypted=
ConditionPathIsEncrypted= is similar to ConditionPathExists=
but verifies that the underlying file system's backing block
device is encrypted using dm-crypt/LUKS. Note that this check
does not cover ext4 per-directory encryption, and only
detects block level encryption. Moreover, if the specified
path resides on a file system on top of a loopback block
device, only encryption above the loopback device is
detected. It is not detected whether the file system backing
the loopback block device is encrypted.
ConditionDirectoryNotEmpty=
ConditionDirectoryNotEmpty= is similar to
ConditionPathExists= but verifies that a certain path exists
and is a non-empty directory.
ConditionFileNotEmpty=
ConditionFileNotEmpty= is similar to ConditionPathExists= but
verifies that a certain path exists and refers to a regular
file with a non-zero size.
ConditionFileIsExecutable=
ConditionFileIsExecutable= is similar to ConditionPathExists=
but verifies that a certain path exists, is a regular file,
and marked executable.
ConditionUser=
ConditionUser= takes a numeric "UID", a UNIX user name, or
the special value "@system". This condition may be used to
check whether the service manager is running as the given
user. The special value "@system" can be used to check if the
user id is within the system user range. This option is not
useful for system services, as the system manager exclusively
runs as the root user, and thus the test result is constant.
ConditionGroup=
ConditionGroup= is similar to ConditionUser= but verifies
that the service manager's real or effective group, or any of
its auxiliary groups, match the specified group or GID. This
setting does not support the special value "@system".
ConditionControlGroupController=
Check whether given cgroup controllers (e.g. "cpu") are
available for use on the system or whether the legacy v1
cgroup or the modern v2 cgroup hierarchy is used.
Multiple controllers may be passed with a space separating
them; in this case the condition will only pass if all listed
controllers are available for use. Controllers unknown to
systemd are ignored. Valid controllers are "cpu", "cpuacct",
"io", "blkio", "memory", "devices", and "pids". Even if
available in the kernel, a particular controller may not be
available if it was disabled on the kernel command line with
cgroup_disable=controller.
Alternatively, two special strings "v1" and "v2" may be
specified (without any controller names). "v2" will pass if
the unified v2 cgroup hierarchy is used, and "v1" will pass
if the legacy v1 hierarchy or the hybrid hierarchy are used
(see the discussion of systemd.unified_cgroup_hierarchy and
systemd.legacy_systemd_cgroup_controller in
systemd.service(5) for more information).
ConditionMemory=
Verify that the specified amount of system memory is
available to the current system. Takes a memory size in bytes
as argument, optionally prefixed with a comparison operator
"<", "<=", "=", "!=", ">=", ">". On bare-metal systems
compares the amount of physical memory in the system with the
specified size, adhering to the specified comparison
operator. In containers compares the amount of memory
assigned to the container instead.
ConditionCPUs=
Verify that the specified number of CPUs is available to the
current system. Takes a number of CPUs as argument,
optionally prefixed with a comparison operator "<", "<=",
"=", "!=", ">=", ">". Compares the number of CPUs in the CPU
affinity mask configured of the service manager itself with
the specified number, adhering to the specified comparison
operator. On physical systems the number of CPUs in the
affinity mask of the service manager usually matches the
number of physical CPUs, but in special and virtual
environments might differ. In particular, in containers the
affinity mask usually matches the number of CPUs assigned to
the container and not the physically available ones.
ConditionCPUFeature=
Verify that a given CPU feature is available via the "CPUID"
instruction. This condition only does something on i386 and
x86-64 processors. On other processors it is assumed that the
CPU does not support the given feature. It checks the leaves
"1", "7", "0x80000001", and "0x80000007". Valid values are:
"fpu", "vme", "de", "pse", "tsc", "msr", "pae", "mce", "cx8",
"apic", "sep", "mtrr", "pge", "mca", "cmov", "pat", "pse36",
"clflush", "mmx", "fxsr", "sse", "sse2", "ht", "pni",
"pclmul", "monitor", "ssse3", "fma3", "cx16", "sse4_1",
"sse4_2", "movbe", "popcnt", "aes", "xsave", "osxsave",
"avx", "f16c", "rdrand", "bmi1", "avx2", "bmi2", "rdseed",
"adx", "sha_ni", "syscall", "rdtscp", "lm", "lahf_lm", "abm",
"constant_tsc".
ConditionOSRelease=
Verify that a specific "key=value" pair is set in the host's
os-release(5).
Other than exact matching with "=", and "!=", relative
comparisons are supported for versioned parameters (e.g.
"VERSION_ID"). The comparator can be one of "<", "<=", "=",
"!=", ">=" and ">".
AssertArchitecture=, AssertVirtualization=, AssertHost=,
AssertKernelCommandLine=, AssertKernelVersion=,
AssertEnvironment=, AssertSecurity=, AssertCapability=,
AssertACPower=, AssertNeedsUpdate=, AssertFirstBoot=,
AssertPathExists=, AssertPathExistsGlob=, AssertPathIsDirectory=,
AssertPathIsSymbolicLink=, AssertPathIsMountPoint=,
AssertPathIsReadWrite=, AssertPathIsEncrypted=,
AssertDirectoryNotEmpty=, AssertFileNotEmpty=,
AssertFileIsExecutable=, AssertUser=, AssertGroup=,
AssertControlGroupController=, AssertMemory=, AssertCPUs=,
AssertOSRelease=
Similar to the ConditionArchitecture=,
ConditionVirtualization=, ..., condition settings described
above, these settings add assertion checks to the start-up of
the unit. However, unlike the conditions settings, any
assertion setting that is not met results in failure of the
start job (which means this is logged loudly). Note that
hitting a configured assertion does not cause the unit to
enter the "failed" state (or in fact result in any state
change of the unit), it affects only the job queued for it.
Use assertion expressions for units that cannot operate when
specific requirements are not met, and when this is something
the administrator or user should look into.
