# systemd.unit

## NAME



           systemd.unit - Unit configuration
    


## SYNOPSIS



           _service_.service, _socket_.socket, _device_.device, _mount_.mount,
           _automount_.automount, _swap_.swap, _target_.target, _path_.path,
           _timer_.timer, _slice_.slice, _scope_.scope
    
       **System Unit Search Path**
               /etc/systemd/system.control/*
               /run/systemd/system.control/*
               /run/systemd/transient/*
               /run/systemd/generator.early/*
               /etc/systemd/system/*
               /etc/systemd/system.attached/*
               /run/systemd/system/*
               /run/systemd/system.attached/*
               /run/systemd/generator/*
               ...
               /usr/local/lib/systemd/system/*
               /usr/lib/systemd/system/*
               /run/systemd/generator.late/*
    
       **User Unit Search Path**
               ~/.config/systemd/user.control/*
               $XDG_RUNTIME_DIR/systemd/user.control/*
               $XDG_RUNTIME_DIR/systemd/transient/*
               $XDG_RUNTIME_DIR/systemd/generator.early/*
               ~/.config/systemd/user/*
               $XDG_CONFIG_DIRS/systemd/user/*
               /etc/systemd/user/*
               $XDG_RUNTIME_DIR/systemd/user/*
               /run/systemd/user/*
               $XDG_RUNTIME_DIR/systemd/generator/*
               $XDG_DATA_HOME/systemd/user/*
               $XDG_DATA_DIRS/systemd/user/*
               ...
               /usr/local/lib/systemd/user/*
               /usr/lib/systemd/user/*
               $XDG_RUNTIME_DIR/systemd/generator.late/*
    


## DESCRIPTION



           A unit file is a plain text ini-style file that encodes
           information about a service, a socket, a device, a mount point, an
           automount point, a swap file or partition, a start-up target, a
           watched file system path, a timer controlled and supervised by
           systemd(1), a resource management slice or a group of externally
           created processes. See systemd.syntax(7) for a general description
           of the syntax.
    
           This man page lists the common configuration options of all the
           unit types. These options need to be configured in the [Unit] or
           [Install] sections of the unit files.
    
           In addition to the generic [Unit] and [Install] sections described
           here, each unit may have a type-specific section, e.g. [Service]
           for a service unit. See the respective man pages for more
           information: systemd.service(5), systemd.socket(5),
           systemd.device(5), systemd.mount(5), systemd.automount(5),
           systemd.swap(5), systemd.target(5), systemd.path(5),
           systemd.timer(5), systemd.slice(5), systemd.scope(5).
    
           Unit files are loaded from a set of paths determined during
           compilation, described in the next section.
    
           Valid unit names consist of a "unit name prefix", and a suffix
           specifying the unit type which begins with a dot. The "unit name
           prefix" must consist of one or more valid characters (ASCII
           letters, digits, ":", "-", "_", ".", and "\"). The total length of
           the unit name including the suffix must not exceed 255 characters.
           The unit type suffix must be one of ".service", ".socket",
           ".device", ".mount", ".automount", ".swap", ".target", ".path",
           ".timer", ".slice", or ".scope".
    
           Unit names can be parameterized by a single argument called the
           "instance name". The unit is then constructed based on a "template
           file" which serves as the definition of multiple services or other
           units. A template unit must have a single "@" at the end of the
           unit name prefix (right before the type suffix). The name of the
           full unit is formed by inserting the instance name between "@" and
           the unit type suffix. In the unit file itself, the instance
           parameter may be referred to using "%i" and other specifiers, see
           below.
    
           Unit files may contain additional options on top of those listed
           here. If systemd encounters an unknown option, it will write a
           warning log message but continue loading the unit. If an option or
           section name is prefixed with **X-** , it is ignored completely by
           systemd. Options within an ignored section do not need the prefix.
           Applications may use this to include additional information in the
           unit files. To access those options, applications need to parse
           the unit files on their own.
    
           Units can be aliased (have an alternative name), by creating a
           symlink from the new name to the existing name in one of the unit
           search paths. For example, systemd-networkd.service has the alias
           dbus-org.freedesktop.network1.service, created during installation
           as a symlink, so when **systemd** is asked through D-Bus to load
           dbus-org.freedesktop.network1.service, it'll load
           systemd-networkd.service. As another example, default.target — the
           default system target started at boot — is commonly aliased to
           either multi-user.target or graphical.target to select what is
           started by default. Alias names may be used in commands like
           **disable** , **start** , **stop** , **status** , and similar, and in all unit
           dependency directives, including _Wants=_ , _Requires=_ , _Before=_ ,
           _After=_. Aliases cannot be used with the **preset** command.
    
           Aliases obey the following restrictions: a unit of a certain type
           (".service", ".socket", ...) can only be aliased by a name with
           the same type suffix. A plain unit (not a template or an
           instance), may only be aliased by a plain name. A template
           instance may only be aliased by another template instance, and the
           instance part must be identical. A template may be aliased by
           another template (in which case the alias applies to all instances
           of the template). As a special case, a template instance (e.g.
           "alias@inst.service") may be a symlink to different template (e.g.
           "template@inst.service"). In that case, just this specific
           instance is aliased, while other instances of the template (e.g.
           "alias@foo.service", "alias@bar.service") are not aliased. Those
           rules preserve the requirement that the instance (if any) is
           always uniquely defined for a given unit and all its aliases. The
           target of alias symlink must point to a valid unit file location,
           i.e. the symlink target name must match the symlink source name as
           described, and the destination path must be in one of the unit
           search paths, see UNIT FILE LOAD PATH section below for more
           details. Note that the target file might not exist, i.e. the
           symlink may be dangling.
    
           Unit files may specify aliases through the _Alias=_ directive in the
           [Install] section. When the unit is enabled, symlinks will be
           created for those names, and removed when the unit is disabled.
           For example, reboot.target specifies _Alias=ctrl-alt-del.target_ , so
           when enabled, the symlink /etc/systemd/system/ctrl-alt-del.target
           pointing to the reboot.target file will be created, and when
           Ctrl+Alt+Del is invoked, **systemd** will look for
           ctrl-alt-del.target, follow the symlink to reboot.target, and
           execute reboot.service as part of that target.  **systemd** does not
           look at the [Install] section at all during normal operation, so
           any directives in that section only have an effect through the
           symlinks created during enablement.
    
           Along with a unit file foo.service, the directory
           foo.service.wants/ may exist. All unit files symlinked from such a
           directory are implicitly added as dependencies of type _Wants=_ to
           the unit. Similar functionality exists for _Requires=_ type
           dependencies as well, the directory suffix is .requires/ in this
           case. This functionality is useful to hook units into the start-up
           of other units, without having to modify their unit files. For
           details about the semantics of _Wants=_ and _Requires=_ , see below.
           The preferred way to create symlinks in the .wants/ or .requires/
           directories is by specifying the dependency in [Install] section
           of the target unit, and creating the symlink in the file system
           with the **enable** or **preset** commands of systemctl(1). The target can
           be a normal unit (either plain or a specific instance of a
           template unit). In case when the source unit is a template, the
           target can also be a template, in which case the instance will be
           "propagated" to the target unit to form a valid unit instance. The
           target of symlinks in .wants/ or .requires/ must thus point to a
           valid unit file location, i.e. the symlink target name must
           satisfy the described requirements, and the destination path must
           be in one of the unit search paths, see UNIT FILE LOAD PATH
           section below for more details. Note that the target file might
           not exist, i.e. the symlink may be dangling.
    
           Along with a unit file foo.service, a "drop-in" directory
           foo.service.d/ may exist. All files with the suffix ".conf" from
           this directory will be merged in the alphanumeric order and parsed
           after the main unit file itself has been parsed. This is useful to
           alter or add configuration settings for a unit, without having to
           modify unit files. Each drop-in file must contain appropriate
           section headers. For instantiated units, this logic will first
           look for the instance ".d/" subdirectory (e.g.
           "foo@bar.service.d/") and read its ".conf" files, followed by the
           template ".d/" subdirectory (e.g.  "foo@.service.d/") and the
           ".conf" files there. Moreover, for unit names containing dashes
           ("-"), the set of directories generated by repeatedly truncating
           the unit name after all dashes is searched too. Specifically, for
           a unit name foo-bar-baz.service not only the regular drop-in
           directory foo-bar-baz.service.d/ is searched but also both
           foo-bar-.service.d/ and foo-.service.d/. This is useful for
           defining common drop-ins for a set of related units, whose names
           begin with a common prefix. This scheme is particularly useful for
           mount, automount and slice units, whose systematic naming
           structure is built around dashes as component separators. Note
           that equally named drop-in files further down the prefix hierarchy
           override those further up, i.e.
           foo-bar-.service.d/10-override.conf overrides
           foo-.service.d/10-override.conf.
    
           In cases of unit aliases (described above), dropins for the
           aliased name and all aliases are loaded. In the example of
           default.target aliasing graphical.target, default.target.d/,
           default.target.wants/, default.target.requires/,
           graphical.target.d/, graphical.target.wants/,
           graphical.target.requires/ would all be read. For templates,
           dropins for the template, any template aliases, the template
           instance, and all alias instances are read. When just a specific
           template instance is aliased, then the dropins for the target
           template, the target template instance, and the alias template
           instance are read.
    
           In addition to /etc/systemd/system, the drop-in ".d/" directories
           for system services can be placed in /usr/lib/systemd/system or
           /run/systemd/system directories. Drop-in files in /etc/ take
           precedence over those in /run/ which in turn take precedence over
           those in /usr/lib/. Drop-in files under any of these directories
           take precedence over unit files wherever located. Multiple drop-in
           files with different names are applied in lexicographic order,
           regardless of which of the directories they reside in.
    
           Units also support a top-level drop-in with _type_.d/, where _type_
           may be e.g.  "service" or "socket", that allows altering or adding
           to the settings of all corresponding unit files on the system. The
           formatting and precedence of applying drop-in configurations
           follow what is defined above. Files in _type_.d/ have lower
           precedence compared to files in name-specific override
           directories. The usual rules apply: multiple drop-in files with
           different names are applied in lexicographic order, regardless of
           which of the directories they reside in, so a file in _type_.d/
           applies to a unit only if there are no drop-ins or masks with that
           name in directories with higher precedence. See Examples.
    
           Note that while systemd offers a flexible dependency system
           between units it is recommended to use this functionality only
           sparingly and instead rely on techniques such as bus-based or
           socket-based activation which make dependencies implicit,
           resulting in a both simpler and more flexible system.
    
           As mentioned above, a unit may be instantiated from a template
           file. This allows creation of multiple units from a single
           configuration file. If systemd looks for a unit configuration
           file, it will first search for the literal unit name in the file
           system. If that yields no success and the unit name contains an
           "@" character, systemd will look for a unit template that shares
           the same name but with the instance string (i.e. the part between
           the "@" character and the suffix) removed. Example: if a service
           getty@tty3.service is requested and no file by that name is found,
           systemd will look for getty@.service and instantiate a service
           from that configuration file if it is found.
    
           To refer to the instance string from within the configuration file
           you may use the special "%i" specifier in many of the
           configuration options. See below for details.
    
           If a unit file is empty (i.e. has the file size 0) or is symlinked
           to /dev/null, its configuration will not be loaded and it appears
           with a load state of "masked", and cannot be activated. Use this
           as an effective way to fully disable a unit, making it impossible
           to start it even manually.
    
           The unit file format is covered by the **Interface Portability and**
           **Stability Promise******[1].


## STRING ESCAPING FOR INCLUSION IN UNIT NAMES



           Sometimes it is useful to convert arbitrary strings into unit
           names. To facilitate this, a method of string escaping is used, in
           order to map strings containing arbitrary byte values (except **NUL**)
           into valid unit names and their restricted character set. A common
           special case are unit names that reflect paths to objects in the
           file system hierarchy. Example: a device unit dev-sda.device
           refers to a device with the device node /dev/sda in the file
           system.
    
           The escaping algorithm operates as follows: given a string, any
           "/" character is replaced by "-", and all other characters which
           are not ASCII alphanumerics, ":", "_" or "."  are replaced by
           C-style "\x2d" escapes. In addition, "."  is replaced with such a
           C-style escape when it would appear as the first character in the
           escaped string.
    
           When the input qualifies as absolute file system path, this
           algorithm is extended slightly: the path to the root directory "/"
           is encoded as single dash "-". In addition, any leading, trailing
           or duplicate "/" characters are removed from the string before
           transformation. Example: /foo//bar/baz/ becomes "foo-bar-baz".
    
           This escaping is fully reversible, as long as it is known whether
           the escaped string was a path (the unescaping results are
           different for paths and non-path strings). The systemd-escape(1)
           command may be used to apply and reverse escaping on arbitrary
           strings. Use **systemd-escape --path** to escape path strings, and
           **systemd-escape** without **--path** otherwise.
    


## AUTOMATIC DEPENDENCIES



       **Implicit Dependencies**
           A number of unit dependencies are implicitly established,
           depending on unit type and unit configuration. These implicit
           dependencies can make unit configuration file cleaner. For the
           implicit dependencies in each unit type, please refer to section
           "Implicit Dependencies" in respective man pages.
    
           For example, service units with _Type=dbus_ automatically acquire
           dependencies of type _Requires=_ and _After=_ on dbus.socket. See
           systemd.service(5) for details.
    
       **Default Dependencies**
           Default dependencies are similar to implicit dependencies, but can
           be turned on and off by setting _DefaultDependencies=_ to _yes_ (the
           default) and _no_ , while implicit dependencies are always in effect.
           See section "Default Dependencies" in respective man pages for the
           effect of enabling _DefaultDependencies=_ in each unit types.
    
           For example, target units will complement all configured
           dependencies of type _Wants=_ or _Requires=_ with dependencies of type
           _After=_. See systemd.target(5) for details. Note that this behavior
           can be opted out by setting _DefaultDependencies=no_ in the
           specified units, or it can be selectively overridden via an
           explicit _Before=_ dependency.
    


## UNIT FILE LOAD PATH



           Unit files are loaded from a set of paths determined during
           compilation, described in the two tables below. Unit files found
           in directories listed earlier override files with the same name in
           directories lower in the list [2].
    
           When the variable _$SYSTEMD_UNIT_PATH_ is set, the contents of this
           variable overrides the unit load path. If _$SYSTEMD_UNIT_PATH_ ends
           with an empty component (":"), the usual unit load path will be
           appended to the contents of the variable.
    
           **Table 1.  Load path when running in system mode (--system).**
           ┌───────────────────────────────┬──────────────────────────┐
           │ **Path** │ **Description** │
           ├───────────────────────────────┼──────────────────────────┤
           │ /etc/systemd/system.control   │ Persistent and transient │
           ├───────────────────────────────┤ configuration created    │
           │ /run/systemd/system.control   │ using the dbus API       │
           ├───────────────────────────────┼──────────────────────────┤
           │ /run/systemd/transient        │ Dynamic configuration    │
           │                               │ for transient units      │
           ├───────────────────────────────┼──────────────────────────┤
           │ /run/systemd/generator.early  │ Generated units with     │
           │                               │ high priority (see       │
           │                               │ _early-dir_ in             │
           │                               │ systemd.generator(7))    │
           ├───────────────────────────────┼──────────────────────────┤
           │ /etc/systemd/system           │ System units created by  │
           │                               │ the administrator        │
           ├───────────────────────────────┼──────────────────────────┤
           │ /run/systemd/system           │ Runtime units            │
           ├───────────────────────────────┼──────────────────────────┤
           │ /run/systemd/generator        │ Generated units with     │
           │                               │ medium priority (see     │
           │                               │ _normal-dir_ in            │
           │                               │ systemd.generator(7))    │
           ├───────────────────────────────┼──────────────────────────┤
           │ /usr/local/lib/systemd/system │ System units installed   │
           │                               │ by the administrator     │
           ├───────────────────────────────┼──────────────────────────┤
           │ /usr/lib/systemd/system       │ System units installed   │
           │                               │ by the distribution      │
           │                               │ package manager          │
           ├───────────────────────────────┼──────────────────────────┤
           │ /run/systemd/generator.late   │ Generated units with low │
           │                               │ priority (see _late-dir_   │
           │                               │ in systemd.generator(7)) │
           └───────────────────────────────┴──────────────────────────┘
    
           **Table 2.  Load path when running in user mode (--user).**
           ┌──────────────────────────────────────────┬──────────────────────────┐
           │ **Path** │ **Description** │
           ├──────────────────────────────────────────┼──────────────────────────┤
           │ $XDG_CONFIG_HOME/systemd/user.control    │ Persistent and transient │
           │ or                                       │ configuration created    │
           │ ~/.config/systemd/user.control           │ using the dbus API       │
           ├──────────────────────────────────────────┤ (_$XDG_CONFIG_HOME_ is     │
           │ $XDG_RUNTIME_DIR/systemd/user.control    │ used if set, ~/.config   │
           │                                          │ otherwise)               │
           ├──────────────────────────────────────────┼──────────────────────────┤
           │ $XDG_RUNTIME_DIR/systemd/transient       │ Dynamic configuration    │
           │                                          │ for transient units      │
           ├──────────────────────────────────────────┼──────────────────────────┤
           │ $XDG_RUNTIME_DIR/systemd/generator.early │ Generated units with     │
           │                                          │ high priority (see       │
           │                                          │ _early-dir_ in             │
           │                                          │ systemd.generator(7))    │
           ├──────────────────────────────────────────┼──────────────────────────┤
           │ $XDG_CONFIG_HOME/systemd/user or         │ User configuration       │
           │ $HOME/.config/systemd/user               │ (_$XDG_CONFIG_HOME_ is     │
           │                                          │ used if set, ~/.config   │
           │                                          │ otherwise)               │
           ├──────────────────────────────────────────┼──────────────────────────┤
           │ $XDG_CONFIG_DIRS/systemd/user or         │ Additional configuration │
           │ /etc/xdg/systemd/user                    │ directories as specified │
           │                                          │ by the XDG base          │
           │                                          │ directory specification  │
           │                                          │ (_$XDG_CONFIG_DIRS_ is     │
           │                                          │ used if set, /etc/xdg    │
           │                                          │ otherwise)               │
           ├──────────────────────────────────────────┼──────────────────────────┤
           │ /etc/systemd/user                        │ User units created by    │
           │                                          │ the administrator        │
           ├──────────────────────────────────────────┼──────────────────────────┤
           │ $XDG_RUNTIME_DIR/systemd/user            │ Runtime units (only used │
           │                                          │ when $XDG_RUNTIME_DIR is │
           │                                          │ set)                     │
           ├──────────────────────────────────────────┼──────────────────────────┤
           │ /run/systemd/user                        │ Runtime units            │
           ├──────────────────────────────────────────┼──────────────────────────┤
           │ $XDG_RUNTIME_DIR/systemd/generator       │ Generated units with     │
           │                                          │ medium priority (see     │
           │                                          │ _normal-dir_ in            │
           │                                          │ systemd.generator(7))    │
           ├──────────────────────────────────────────┼──────────────────────────┤
           │ $XDG_DATA_HOME/systemd/user or           │ Units of packages that   │
           │ $HOME/.local/share/systemd/user          │ have been installed in   │
           │                                          │ the home directory       │
           │                                          │ (_$XDG_DATA_HOME_ is used  │
           │                                          │ if set, ~/.local/share   │
           │                                          │ otherwise)               │
           ├──────────────────────────────────────────┼──────────────────────────┤
           │ $XDG_DATA_DIRS/systemd/user or           │ Additional data          │
           │ /usr/local/share/systemd/user and        │ directories as specified │
           │ /usr/share/systemd/user                  │ by the XDG base          │
           │                                          │ directory specification  │
           │                                          │ (_$XDG_DATA_DIRS_ is used  │
           │                                          │ if set, /usr/local/share │
           │                                          │ and /usr/share           │
           │                                          │ otherwise)               │
           ├──────────────────────────────────────────┼──────────────────────────┤
           │ $dir/systemd/user for each _$dir_ in       │ Additional locations for │
           │ _$XDG_DATA_DIRS_                           │ installed user units,    │
           │                                          │ one for each entry in    │
           │                                          │ _$XDG_DATA_DIRS_           │
           ├──────────────────────────────────────────┼──────────────────────────┤
           │ /usr/local/lib/systemd/user              │ User units installed by  │
           │                                          │ the administrator        │
           ├──────────────────────────────────────────┼──────────────────────────┤
           │ /usr/lib/systemd/user                    │ User units installed by  │
           │                                          │ the distribution package │
           │                                          │ manager                  │
           ├──────────────────────────────────────────┼──────────────────────────┤
           │ $XDG_RUNTIME_DIR/systemd/generator.late  │ Generated units with low │
           │                                          │ priority (see _late-dir_   │
           │                                          │ in systemd.generator(7)) │
           └──────────────────────────────────────────┴──────────────────────────┘
    
           The set of load paths for the user manager instance may be
           augmented or changed using various environment variables. And
           environment variables may in turn be set using environment
           generators, see systemd.environment-generator(7). In particular,
           _$XDG_DATA_HOME_ and _$XDG_DATA_DIRS_ may be easily set using
           systemd-environment-d-generator(8). Thus, directories listed here
           are just the defaults. To see the actual list that would be used
           based on compilation options and current environment use
    
               systemd-analyze --user unit-paths
    
           Moreover, additional units might be loaded into systemd from
           directories not on the unit load path by creating a symlink
           pointing to a unit file in the directories. You can use **systemctl**
           **link** for this; see systemctl(1). The file system where the linked
           unit files are located must be accessible when systemd is started
           (e.g. anything underneath /home/ or /var/ is not allowed, unless
           those directories are located on the root file system).
    
           It is important to distinguish "linked unit files" from "unit file
           aliases": any symlink where the symlink _target_ is within the unit
           load path becomes an alias: the source name and the target file
           name must satisfy specific constraints listed above in the
           discussion of aliases, but the symlink target does not have to
           exist, and in fact the symlink target path is not used, except to
           check whether the target is within the unit load path. In
           contrast, a symlink which goes outside of the unit load path
           signifies a linked unit file. The symlink is followed when loading
           the file, but the destination name is otherwise unused (and may
           even not be a valid unit file name). For example, symlinks
           /etc/systemd/system/alias1.service → service1.service,
           /etc/systemd/system/alias2.service →
           /usr/lib/systemd/service1.service,
           /etc/systemd/system/alias3.service →
           /etc/systemd/system/service1.service are all valid aliases and
           service1.service will have four names, even if the unit file is
           located at /run/systemd/system/service1.service. In contrast, a
           symlink /etc/systemd/system/link1.service → ../link1_service_file
           means that link1.service is a "linked unit" and the contents of
           /etc/systemd/link1_service_file provide its configuration.
    


## UNIT GARBAGE COLLECTION



           The system and service manager loads a unit's configuration
           automatically when a unit is referenced for the first time. It
           will automatically unload the unit configuration and state again
           when the unit is not needed anymore ("garbage collection"). A unit
           may be referenced through a number of different mechanisms:
    
            1. Another loaded unit references it with a dependency such as
               _After=_ , _Wants=_ , ...
    
            2. The unit is currently starting, running, reloading or
               stopping.
    
            3. The unit is currently in the **failed** state. (But see below.)
    
            4. A job for the unit is pending.
    
            5. The unit is pinned by an active IPC client program.
    
            6. The unit is a special "perpetual" unit that is always active
               and loaded. Examples for perpetual units are the root mount
               unit -.mount or the scope unit init.scope that the service
               manager itself lives in.
    
            7. The unit has running processes associated with it.
    
           The garbage collection logic may be altered with the _CollectMode=_
           option, which allows configuration whether automatic unloading of
           units that are in **failed** state is permissible, see below.
    
           Note that when a unit's configuration and state is unloaded, all
           execution results, such as exit codes, exit signals, resource
           consumption and other statistics are lost, except for what is
           stored in the log subsystem.
    
           Use **systemctl daemon-reload** or an equivalent command to reload
           unit configuration while the unit is already loaded. In this case,
           all configuration settings are flushed out and replaced with the
           new configuration (which however might not be in effect
           immediately), however all runtime state is saved/restored.
    


## [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 brief, meaningful, human-readable text identifying the unit.
               This may be used by **systemd**(and suitable UIs) as a
               user-visible label for the unit, so this string should
               identify the unit rather than just describe it, despite the
               name. This string also should not just repeat the unit name.
               "Apache HTTP Server" or "Postfix Mail Server" are good
               examples. Bad examples are "high-performance lightweight HTTP
               server" (too generic) or "Apache" (meaningless for people who
               do not know the Apache HTTP server project, 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 verb conjugated in the
               present continuous, or end in a full stop. Bad examples
               include "exiting the container", "updating the database once
               per day.", or "OpenSSH server second instance daemon".
    
               Added in version 201.
    
           _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.
    
               Added in version 201.
    
           _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.
    
               Added in version 201.
    
           _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 (or
               restarted) if one of the other units is explicitly stopped (or
               restarted).
    
               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).
    
               Added in version 201.
    
           _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.
    
               Added in version 201.
    
           _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 an
               unmet 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.
    
               Added in version 201.
    
           _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.
    
               Added in version 201.
    
           _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. The restart happens without delay, and usual per-unit
               rate-limit applies.
    
               When _Upholds=b.service_ is used on a.service, this dependency
               will show as _UpheldBy=a.service_ in the property listing of
               b.service.
    
               Added in version 249.
    
           _Conflicts=_
               A space-separated list of unit names. Configures negative
               requirement dependencies. If a unit has a _Conflicts=_
               requirement on a set of other units, then starting it will
               stop all of them and starting any of them will stop it.
    
               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 does not 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.
    
               Added in version 201.
    
           _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 does not matter if
               the ordering dependency is _After=_ or _Before=_ , in this case. It
               also does not 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 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.
    
               Added in version 201.
    
           _OnFailure=_
               A space-separated list of one or more units that are activated
               when this unit enters the "failed" state.
    
               Added in version 201.
    
           _OnSuccess=_
               A space-separated list of one or more units that are activated
               when this unit enters the "inactive" state.
    
               Added in version 249.
    
           _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.
    
               Added in version 201.
    
           _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.
    
               Added in version 249.
    
           _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. If this is specified on a unit (say,
               a.service has _JoinsNamespaceOf=b.service_), then the inverse
               dependency (_JoinsNamespaceOf=a.service_ for b.service) is
               implied. 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 and these do not share their namespace, then 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.
    
               Added in version 209.
    
           _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.
    
               Added in version 201.
    
           _WantsMountsFor=_
               Same as _RequiresMountsFor=_ , but adds dependencies of type
               _Wants=_ instead of _Requires=_.
    
               Added in version 256.
    
           _OnSuccessJobMode=_ , _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 _OnSuccess=_ /_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 _OnSuccess=_ /_OnFailure=_.
    
               Added in version 209.
    
           _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.
    
               Added in version 201.
    
           _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**.
    
               Added in version 201.
    
           _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**.
    
               Added in version 201.
    
           _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**.
    
               Added in version 201.
    
           _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.
    
               Added in version 201.
    
           _SurviveFinalKillSignal=_
               Takes a boolean argument. Defaults to **no**. If **yes** , processes
               belonging to this unit will not be sent the final "SIGTERM"
               and "SIGKILL" signals during the final phase of the system
               shutdown process. This functionality replaces the older
               mechanism that allowed a program to set "argv[0][0] = '@'" as
               described at **systemd and Storage Daemons for the Root File**
               **System******[3], which however continues to be supported.
    
               Added in version 255._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**.
    
               Added in version 236.
    
           _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** , **exit-force** , **soft-reboot** ,
               **soft-reboot-force** , **kexec** , **kexec-force** , **halt** , **halt-force** and
               **halt-immediate**. 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** ,
               **kexec** , **kexec-force** , **halt** , **halt-force** and **halt-immediate** have
               the effect of powering down the system, executing kexec, and
               halting the system respectively 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.
               **soft-reboot** will trigger a userspace reboot operation.
               **soft-reboot-force** does that too, but does not go through the
               shutdown transaction beforehand.
    
               Added in version 236.
    
           _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.
    
               Added in version 240.
    
           _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(7). The default is "infinity" (job timeouts
               disabled), except for device units where _JobRunningTimeoutSec=_
               defaults to _DefaultDeviceTimeoutSec=_.
    
               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.
    
               Added in version 201.
    
           _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 _FailureAction=_ /_SuccessAction=_. Defaults to
               **none**.
    
               _JobTimeoutRebootArgument=_ configures an optional reboot string
               to pass to the reboot(2) system call.
    
               Added in version 240.
    
           _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(7). The special
               value "infinity" can be used to limit the total number of
               start attempts, even if they happen at large time intervals.
               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.
    
               Added in version 229.
    
           _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**.
    
               Added in version 229.
    
           _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.
    
               Added in version 229.
    
           _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.
    
               Added in version 201.
    
       **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 does not 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 unmet
           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".
    
               Use systemd-analyze(1) for the complete list of known
               architectures.
    
               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.
    
               Added in version 201.
    
           _ConditionFirmware=_
               Check whether the system's firmware is of a certain type. The
               following values are possible:
    
               •   "uefi" matches systems with EFI.
    
               •   "device-tree" matches systems with a device tree.
    
               •   "device-tree-compatible(_value_)" matches systems with a
                   device tree that are compatible with "value".
    
               •   "smbios-field(_field operator value_)" matches systems with
                   a SMBIOS field containing a certain value.  _field_ is the
                   name of the SMBIOS field exposed as "sysfs" attribute file
                   below /sys/class/dmi/id/.  _operator_ is one of "<", "<=",
                   ">=", ">", "==", "<>" for version comparisons, "=" and
                   "!=" for literal string comparisons, or "$=", "!$=" for
                   shell-style glob comparisons.  _value_ is the expected value
                   of the SMBIOS field value (possibly containing shell style
                   globs in case "$="/"!$=" is used).
    
               Added in version 249.
    
           _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", "apple", "sre", "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.
    
               Added in version 244.
    
           _ConditionHost=_
               _ConditionHost=_ may be used to match against the hostname,
               machine ID, boot ID or product UUID 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 128bit ID or UUID, formatted as
               string. The latter is compared against machine ID, boot ID and
               the firmware product UUID if there is any. See machine-id(5)
               for details about the machine ID. The test may be negated by
               prepending an exclamation mark.
    
               Added in version 244.
    
           _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).
    
               Added in version 244.
    
           _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. The argument must be a list of (potentially quoted)
               expressions. Each expression starts with one of "=" or "!="
               for string comparisons, "<", "<=", "==", "<>", ">=", ">" for
               version comparisons, or "$=", "!$=" for a shell-style glob
               match. If no operator is specified, "$=" is implied.
    
               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.
    
               Added in version 244.
    
           _ConditionVersion=_
               _ConditionVersion=_ may be used to check whether a software
               version matches a certain expression, or if prefixed with the
               exclamation mark, does not match. The first argument is the
               software whose version has to be checked. Currently "kernel",
               "systemd" and "glibc" are supported. If this argument is
               omitted, "kernel" is implied. The second argument must be a
               list of (potentially quoted) expressions. Each expression
               starts with one of "=" or "!=" for string comparisons, "<",
               "<=", "==", "<>", ">=", ">" for version comparisons, or "$=",
               "!$=" for a shell-style glob match. If no operator is
               specified, "$=" is implied.
    
               Added in version 258.
    
           _ConditionCredential=_
               _ConditionCredential=_ may be used to check whether a credential
               by the specified name was passed into the service manager. See
               **System and Service Credentials******[4] for details about
               credentials. If used in services for the system service
               manager this may be used to conditionalize services based on
               system credentials passed in. If used in services for the
               per-user service manager this may be used to conditionalize
               services based on credentials passed into the unit@.service
               service instance belonging to the user. The argument must be a
               valid credential name.
    
               Added in version 252._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.
    
               Added in version 246.
    
           _ConditionSecurity=_
               _ConditionSecurity=_ may be used to check whether the given
               security technology is enabled on the system. Currently, the
               following values are recognized:
    
               **Table 3. Recognized security technologies**
               ┌─────────────────┬─────────────────────────┐
               │ **Value** │ **Description** │
               ├─────────────────┼─────────────────────────┤
               │ selinux         │ SELinux MAC             │
               ├─────────────────┼─────────────────────────┤
               │ apparmor        │ AppArmor MAC            │
               ├─────────────────┼─────────────────────────┤
               │ tomoyo          │ Tomoyo MAC              │
               ├─────────────────┼─────────────────────────┤
               │ smack           │ SMACK MAC               │
               ├─────────────────┼─────────────────────────┤
               │ ima             │ Integrity Measurement   │
               │                 │ Architecture (IMA)      │
               ├─────────────────┼─────────────────────────┤
               │ audit           │ Linux Audit Framework   │
               ├─────────────────┼─────────────────────────┤
               │ uefi-secureboot │ UEFI SecureBoot         │
               ├─────────────────┼─────────────────────────┤
               │ tpm2            │ Trusted Platform Module │
               │                 │ 2.0 (TPM2)              │
               ├─────────────────┼─────────────────────────┤
               │ cvm             │ Confidential virtual    │
               │                 │ machine (SEV/TDX)       │
               ├─────────────────┼─────────────────────────┤
               │ measured-uki    │ Unified Kernel Image    │
               │                 │ with PCR 11             │
               │                 │ Measurements, as per    │
               │                 │ systemd-stub(7). Added  │
               │                 │ in version 255.         │
               └─────────────────┴─────────────────────────┘
    
               The test may be negated by prepending an exclamation mark.
    
               Added in version 244.
    
           _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.
    
               Added in version 244.
    
           _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.
    
               Added in version 244.
    
           _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.
    
               Added in version 244.
    
           _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/ was unpopulated
               when the system started booting (for details, see "First Boot
               Semantics" in machine-id(5)). First Boot is considered
               finished (this condition will evaluate as false) after the
               manager has finished the startup phase.
    
               This condition 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.
    
               Note that the service manager itself will perform setup steps
               during First Boot: it will initialize machine-id(5) and preset
               all units, enabling or disabling them according to the
               systemd.preset(5) settings. Additional setup may be performed
               via units with _ConditionFirstBoot=yes_.
    
               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.
    
               Added in version 244.
    
           _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.
    
               Added in version 244.
    
           _ConditionPathExistsGlob=_
               _ConditionPathExistsGlob=_ is similar to _ConditionPathExists=_ ,
               but checks for the existence of at least one file or directory
               matching the specified globbing pattern.
    
               Added in version 244.
    
           _ConditionPathIsDirectory=_
               _ConditionPathIsDirectory=_ is similar to _ConditionPathExists=_
               but verifies that a certain path exists and is a directory.
    
               Added in version 244.
    
           _ConditionPathIsSymbolicLink=_
               _ConditionPathIsSymbolicLink=_ is similar to
               _ConditionPathExists=_ but verifies that a certain path exists
               and is a symbolic link.
    
               Added in version 244.
    
           _ConditionPathIsMountPoint=_
               _ConditionPathIsMountPoint=_ is similar to _ConditionPathExists=_
               but verifies that a certain path exists and is a mount point.
    
               Added in version 244.
    
           _ConditionPathIsReadWrite=_
               _ConditionPathIsReadWrite=_ is similar to _ConditionPathExists=_
               but verifies that the underlying file system is readable and
               writable (i.e. not mounted read-only).
    
               Added in version 244.
    
           _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.
    
               Added in version 246.
    
           _ConditionDirectoryNotEmpty=_
               _ConditionDirectoryNotEmpty=_ is similar to _ConditionPathExists=_
               but verifies that a certain path exists and is a non-empty
               directory.
    
               Added in version 244.
    
           _ConditionFileNotEmpty=_
               _ConditionFileNotEmpty=_ is similar to _ConditionPathExists=_ but
               verifies that a certain path exists and refers to a regular
               file with a non-zero size.
    
               Added in version 244.
    
           _ConditionFileIsExecutable=_
               _ConditionFileIsExecutable=_ is similar to _ConditionPathExists=_
               but verifies that a certain path exists, is a regular file,
               and marked executable.
    
               Added in version 244.
    
           _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.
    
               Added in version 244.
    
           _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".
    
               Added in version 244.
    
           _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", "io",
               "memory", 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. Note
               that legacy or hybrid hierarchies have been deprecated. See
               systemd(1) for more information.
    
               Added in version 244.
    
           _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 "<",
               "<=", "=" (or "=="), "!=" (or "<>"), ">=", ">". 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.
    
               Added in version 244.
    
           _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 "<", "<=", "=" (or "=="),
               "!=" (or "<>"), ">=", ">". 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.
    
               Added in version 244.
    
           _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".
    
               Added in version 248.
    
           _ConditionOSRelease=_
               Verify that a specific "key=value" pair is set in the host's
               os-release(5).
    
               Other than exact string matching (with "=" and "!="), relative
               comparisons are supported for versioned parameters (e.g.
               "VERSION_ID"; with "<", "<=", "==", "<>", ">=", ">"), and
               shell-style wildcard comparisons ("*", "?", "[]") are
               supported with the "$=" (match) and "!$=" (non-match).
    
               If the given key is not found in the file, the match is done
               against an empty value.
    
               Added in version 249.
    
           _ConditionMemoryPressure=_ , _ConditionCPUPressure=_ ,
           _ConditionIOPressure=_
               Verify that the overall system (memory, CPU or IO) pressure is
               below or equal to a threshold. This setting takes a threshold
               value as argument. It can be specified as a simple percentage
               value, suffixed with "%", in which case the pressure will be
               measured as an average over the last five minutes before the
               attempt to start the unit is performed. Alternatively, the
               average timespan can also be specified using "/" as a
               separator, for example: "10%/1min". The supported timespans
               match what the kernel provides, and are limited to "10sec",
               "1min" and "5min". The "full" PSI will be checked first, and
               if not found "some" will be checked. For more details, see the
               documentation on **PSI (Pressure Stall Information)******[5].
    
               Optionally, the threshold value can be prefixed with the slice
               unit under which the pressure will be checked, followed by a
               ":". If the slice unit is not specified, the overall system
               pressure will be measured, instead of a particular cgroup's.
    
               Added in version 250._ConditionKernelModuleLoaded=_
               Test whether the specified kernel module has been loaded and
               is already fully initialized.
    
               Added in version 258.
    
           _AssertArchitecture=_ , _AssertVirtualization=_ , _AssertHost=_ ,
           _AssertKernelCommandLine=_ , _AssertKernelVersion=_ , _AssertVersion=_ ,
           _AssertCredential=_ , _AssertEnvironment=_ , _AssertSecurity=_ ,
           _AssertCapability=_ , _AssertACPower=_ , _AssertNeedsUpdate=_ ,
           _AssertFirstBoot=_ , _AssertPathExists=_ , _AssertPathExistsGlob=_ ,
           _AssertPathIsDirectory=_ , _AssertPathIsSymbolicLink=_ ,
           _AssertPathIsMountPoint=_ , _AssertPathIsReadWrite=_ ,
           _AssertPathIsEncrypted=_ , _AssertDirectoryNotEmpty=_ ,
           _AssertFileNotEmpty=_ , _AssertFileIsExecutable=_ , _AssertUser=_ ,
           _AssertGroup=_ , _AssertControlGroupController=_ , _AssertMemory=_ ,
           _AssertCPUs=_ , _AssertCPUFeature=_ , _AssertOSRelease=_ ,
           _AssertMemoryPressure=_ , _AssertCPUPressure=_ , _AssertIOPressure=_ ,
           _AssertKernelModuleLoaded=_
               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.
    
               Added in version 218.
    


## MAPPING OF UNIT PROPERTIES TO THEIR INVERSES



           Unit settings that create a relationship with a second unit
           usually show up in properties of both units, for example in
           **systemctl show** output. In some cases the name of the property is
           the same as the name of the configuration setting, but not always.
           This table lists the properties that are shown on two units which
           are connected through some dependency, and shows which property on
           "source" unit corresponds to which property on the "target" unit.
    
           **Table 4.  Forward and reverse unit properties**
           ┌───────────────────────┬───────────────────────┬───────────────────────────────┐
           │ **"Forward"** │ **"Reverse"** │ **Where used** │
           │ **property** │ **property** │                               │
           ├───────────────────────┼───────────────────────┼───────────────────────────────┤
           │ _Before=_               │ _After=_                │                               │
           ├───────────────────────┼───────────────────────┤ [Unit] section                │
           │ _After=_                │ _Before=_               │                               │
           ├───────────────────────┼───────────────────────┼────────────────┬──────────────┤
           │ _Requires=_             │ _RequiredBy=_           │ [Unit] section │ [Install]    │
           │                       │                       │                │ section      │
           ├───────────────────────┼───────────────────────┼────────────────┼──────────────┤
           │ _Wants=_                │ _WantedBy=_             │ [Unit] section │ [Install]    │
           │                       │                       │                │ section      │
           ├───────────────────────┼───────────────────────┼────────────────┼──────────────┤
           │ _Upholds=_              │ _UpheldBy=_             │ [Unit] section │ [Install]    │
           │                       │                       │                │ section      │
           ├───────────────────────┼───────────────────────┼────────────────┼──────────────┤
           │ _PartOf=_               │ _ConsistsOf=_           │ [Unit] section │ an automatic │
           │                       │                       │                │ property     │
           ├───────────────────────┼───────────────────────┼────────────────┼──────────────┤
           │ _BindsTo=_              │ _BoundBy=_              │ [Unit] section │ an automatic │
           │                       │                       │                │ property     │
           ├───────────────────────┼───────────────────────┼────────────────┼──────────────┤
           │ _Requisite=_            │ _RequisiteOf=_          │ [Unit] section │ an automatic │
           │                       │                       │                │ property     │
           ├───────────────────────┼───────────────────────┼────────────────┼──────────────┤
           │ _Conflicts=_            │ _ConflictedBy=_         │ [Unit] section │ an automatic │
           │                       │                       │                │ property     │
           ├───────────────────────┼───────────────────────┼────────────────┴──────────────┤
           │ _Triggers=_             │ _TriggeredBy=_          │ Automatic properties, see     │
           │                       │                       │ notes below                   │
           ├───────────────────────┼───────────────────────┼───────────────────────────────┤
           │ _PropagatesReloadTo=_   │ _ReloadPropagatedFrom=_ │                               │
           ├───────────────────────┼───────────────────────┤ [Unit] section                │
           │ _ReloadPropagatedFrom=_ │ _PropagatesReloadTo=_   │                               │
           ├───────────────────────┼───────────────────────┼───────────────────────────────┤
           │ _PropagatesStopTo=_     │ _StopPropagatedFrom=_   │                               │
           ├───────────────────────┼───────────────────────┤ [Unit] section                │
           │ _StopPropagatedFrom=_   │ _PropagatesStopTo=_     │                               │
           ├───────────────────────┼───────────────────────┼────────────────┬──────────────┤
           │ _Following=_            │ n/a                   │ An automatic   │              │
           │                       │                       │ property       │              │
           └───────────────────────┴───────────────────────┴────────────────┴──────────────┘
    
           Note: _WantedBy=_ , _RequiredBy=_ , and _UpheldBy=_ are used in the
           [Install] section to create symlinks in .wants/, .requires/, and
           .upholds/ directories. They cannot be used directly as a unit
           configuration setting.
    
           Note: _ConsistsOf=_ , _BoundBy=_ , _RequisiteOf=_ , _ConflictedBy=_ are
           created implicitly along with their reverses and cannot be
           specified directly.
    
           Note: _Triggers=_ is created implicitly between a socket, path unit,
           or an automount unit, and the unit they activate. By default, a
           unit with the same name is triggered, but this can be overridden
           using _Sockets=_ , _Service=_ , and _Unit=_ settings. See
           systemd.service(5), systemd.socket(5), systemd.path(5), and
           systemd.automount(5) for details.  _TriggeredBy=_ is created
           implicitly on the triggered unit.
    
           Note: _Following=_ is used to group device aliases and points to the
           "primary" device unit that systemd is using to track device state,
           usually corresponding to a sysfs path. It does not show up in the
           "target" unit.
    


## [INSTALL] SECTION OPTIONS



           Unit files may include an [Install] section, which carries
           installation information for the unit. This section is not
           interpreted by systemd(1) during runtime; it is used by the **enable**
           and **disable** commands of the systemctl(1) tool during installation
           of a unit.
    
           _Alias=_
               A space-separated list of additional names this unit shall be
               installed under. The names listed here must have the same
               suffix (i.e. type) as the unit filename. This option may be
               specified more than once, in which case all listed names are
               used. At installation time, **systemctl enable** will create
               symlinks from these names to the unit filename. Note that not
               all unit types support such alias names, and this setting is
               not supported for them. Specifically, mount, slice, swap, and
               automount units do not support aliasing.
    
               Added in version 201.
    
           _WantedBy=_ , _RequiredBy=_ , _UpheldBy=_
               This option may be used more than once, or a space-separated
               list of unit names may be given. A symbolic link is created in
               the .wants/, .requires/, or .upholds/ directory of each of the
               listed units when this unit is installed by **systemctl enable**.
               This has the effect of a dependency of type _Wants=_ , _Requires=_ ,
               or _Upholds=_ being added from the listed unit to the current
               unit. See the description of the mentioned dependency types in
               the [Unit] section for details.
    
               In case of template units listing non template units, the
               listing unit must have _DefaultInstance=_ set, or **systemctl**
               **enable** must be called with an instance name. The instance
               (default or specified) will be added to the .wants/,
               .requires/, or .upholds/ list of the listed unit. For example,
               **WantedBy=getty.target** in a service getty@.service will result
               in **systemctl enable getty@tty2.service** creating a
               getty.target.wants/getty@tty2.service link to getty@.service.
               This also applies to listing specific instances of templated
               units: this specific instance will gain the dependency. A
               template unit may also list a template unit, in which case a
               generic dependency will be added where each instance of the
               listing unit will have a dependency on an instance of the
               listed template with the same instance value. For example,
               **WantedBy=container@.target** in a service monitor@.service will
               result in **systemctl enable monitor@.service** creating a
               container@.target.wants/monitor@.service link to
               monitor@.service, which applies to all instances of
               container@.target.
    
               Added in version 201.
    
           _Also=_
               Additional units to install/deinstall when this unit is
               installed/deinstalled. If the user requests
               installation/deinstallation of a unit with this option
               configured, **systemctl enable** and **systemctl disable** will
               automatically install/uninstall units listed in this option as
               well.
    
               This option may be used more than once, or a space-separated
               list of unit names may be given.
    
               Added in version 201.
    
           _DefaultInstance=_
               In template unit files, this specifies for which instance the
               unit shall be enabled if the template is enabled without any
               explicitly set instance. This option has no effect in
               non-template unit files. The specified string must be usable
               as instance identifier.
    
               Added in version 215.
    
           The following specifiers are interpreted in the Install section:
           %a, %b, %B, %g, %G, %H, %i, %j, %l, %m, %n, %N, %o, %p, %u, %U,
           %v, %w, %W, %%. For their meaning see the next section.
    


## SPECIFIERS



           Many settings resolve specifiers which may be used to write
           generic unit files referring to runtime or unit parameters that
           are replaced when the unit files are loaded. Specifiers must be
           known and resolvable for the setting to be valid. The following
           specifiers are understood:
    
           **Table 5. Specifiers available in unit files**
           ┌───────────┬────────────────────┬──────────────────────────┐
           │ **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=_   │
           │           │                    │ above 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.             │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%C"      │ Cache directory    │ This is either           │
           │           │ root               │ /var/cache (for the      │
           │           │                    │ system manager) or the   │
           │           │                    │ path "$XDG_CACHE_HOME"   │
           │           │                    │ resolves to (for user    │
           │           │                    │ managers).               │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%d"      │ Credentials        │ This is the value of     │
           │           │ directory          │ the                      │
           │           │                    │ "$CREDENTIALS_DIRECTORY" │
           │           │                    │ environment variable     │
           │           │                    │ if available. See        │
           │           │                    │ section "Credentials"    │
           │           │                    │ in systemd.exec(5) for   │
           │           │                    │ more information.        │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%D"      │ Shared data        │ This is either           │
           │           │ directory          │ /usr/share/ (for the     │
           │           │                    │ system manager) or the   │
           │           │                    │ path "$XDG_DATA_HOME"    │
           │           │                    │ resolves to (for user    │
           │           │                    │ managers).               │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%E"      │ Configuration      │ This is either /etc/     │
           │           │ directory root     │ (for the system manager) │
           │           │                    │ or the path              │
           │           │                    │ "$XDG_CONFIG_HOME"       │
           │           │                    │ resolves to (for user    │
           │           │                    │ managers).               │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%f"      │ Unescaped filename │ This is either the       │
           │           │                    │ unescaped instance name  │
           │           │                    │ (if applicable) with /   │
           │           │                    │ prepended (if            │
           │           │                    │ applicable), or the      │
           │           │                    │ unescaped prefix name    │
           │           │                    │ prepended with /. This   │
           │           │                    │ implements unescaping    │
           │           │                    │ according to the rules   │
           │           │                    │ for escaping absolute    │
           │           │                    │ file system paths        │
           │           │                    │ discussed above.         │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%g"      │ User group         │ This is the name of the  │
           │           │                    │ group running the        │
           │           │                    │ service manager          │
           │           │                    │ instance. In case of the │
           │           │                    │ system manager this      │
           │           │                    │ resolves to "root".      │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%G"      │ User GID           │ This is the numeric GID  │
           │           │                    │ of the user running the  │
           │           │                    │ service manager          │
           │           │                    │ instance. In case of the │
           │           │                    │ system manager this      │
           │           │                    │ resolves to "0".         │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%h"      │ User home          │ This is the home         │
           │           │ directory          │ directory of the _user_    │
           │           │                    │ _running the service_      │
           │           │                    │ _manager instance_. In     │
           │           │                    │ case of the system       │
           │           │                    │ manager this resolves to │
           │           │                    │ "/root".                 │
           │           │                    │                          │
           │           │                    │ Note that this setting   │
           │           │                    │ is _not_ influenced by the │
           │           │                    │ _User=_ setting            │
           │           │                    │ configurable in the      │
           │           │                    │ [Service] section of the │
           │           │                    │ service unit.            │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%H"      │ Host name          │ The hostname of the      │
           │           │                    │ running system at the    │
           │           │                    │ point in time the unit   │
           │           │                    │ configuration is loaded. │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%i"      │ Instance name      │ For instantiated units   │
           │           │                    │ this is the string       │
           │           │                    │ between the first "@"    │
           │           │                    │ character and the type   │
           │           │                    │ suffix. Empty for        │
           │           │                    │ non-instantiated units.  │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%I"      │ Unescaped instance │ Same as "%i", but with   │
           │           │ name               │ escaping undone.         │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%j"      │ Final component of │ This is the string       │
           │           │ the prefix         │ between the last "-" and │
           │           │                    │ the end of the prefix    │
           │           │                    │ name. If there is no     │
           │           │                    │ "-", this is the same as │
           │           │                    │ "%p".                    │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%J"      │ Unescaped final    │ Same as "%j", but with   │
           │           │ component of the   │ escaping undone.         │
           │           │ prefix             │                          │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%l"      │ Short host name    │ The hostname of the      │
           │           │                    │ running system at the    │
           │           │                    │ point in time the unit   │
           │           │                    │ configuration is loaded, │
           │           │                    │ truncated at the first   │
           │           │                    │ dot to remove any domain │
           │           │                    │ component.               │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%L"      │ Log directory root │ This is either /var/log  │
           │           │                    │ (for the system manager) │
           │           │                    │ or the path              │
           │           │                    │ _$XDG_STATE_HOME_ resolves │
           │           │                    │ to with /log appended    │
           │           │                    │ (for user managers).     │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%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.             │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%n"      │ Full unit name     │                          │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%N"      │ Full unit name     │ Same as "%n", but with   │
           │           │                    │ the type suffix removed. │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%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.             │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%p"      │ Prefix name        │ For instantiated units,  │
           │           │                    │ this refers to the       │
           │           │                    │ string before the first  │
           │           │                    │ "@" character of the     │
           │           │                    │ unit name. For           │
           │           │                    │ non-instantiated units,  │
           │           │                    │ same as "%N".            │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%P"      │ Unescaped prefix   │ Same as "%p", but with   │
           │           │ name               │ escaping undone.         │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%q"      │ Pretty host name   │ The pretty hostname of   │
           │           │                    │ the running system at    │
           │           │                    │ the point in time the    │
           │           │                    │ unit configuration is    │
           │           │                    │ loaded, as read from the │
           │           │                    │ _PRETTY_HOSTNAME=_ field   │
           │           │                    │ of /etc/machine-info. If │
           │           │                    │ not set, resolves to the │
           │           │                    │ short hostname. See      │
           │           │                    │ machine-info(5) for more │
           │           │                    │ information.             │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%s"      │ User shell         │ This is the shell of the │
           │           │                    │ user running the service │
           │           │                    │ manager instance.        │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%S"      │ State directory    │ This is either /var/lib  │
           │           │ root               │ (for the system manager) │
           │           │                    │ or the path              │
           │           │                    │ _$XDG_STATE_HOME_ resolves │
           │           │                    │ to (for user managers).  │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%t"      │ Runtime directory  │ This is either /run/     │
           │           │ root               │ (for the system manager) │
           │           │                    │ or the path              │
           │           │                    │ "$XDG_RUNTIME_DIR"       │
           │           │                    │ resolves to (for user    │
           │           │                    │ managers).               │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%T"      │ Directory for      │ This is either /tmp or   │
           │           │ temporary files    │ the path "$TMPDIR",      │
           │           │                    │ "$TEMP" or "$TMP" are    │
           │           │                    │ set to. (Note that the   │
           │           │                    │ directory may be         │
           │           │                    │ specified without a      │
           │           │                    │ trailing slash.)         │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%u"      │ User name          │ This is the name of the  │
           │           │                    │ _user running the service_ │
           │           │                    │ _manager instance_. In     │
           │           │                    │ case of the system       │
           │           │                    │ manager this resolves to │
           │           │                    │ "root".                  │
           │           │                    │                          │
           │           │                    │ Note that this setting   │
           │           │                    │ is _not_ influenced by the │
           │           │                    │ _User=_ setting            │
           │           │                    │ configurable in the      │
           │           │                    │ [Service] section of the │
           │           │                    │ service unit.            │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%U"      │ User UID           │ This is the numeric UID  │
           │           │                    │ of the _user running the_  │
           │           │                    │ _service manager_          │
           │           │                    │ _instance_. In case of the │
           │           │                    │ system manager this      │
           │           │                    │ resolves to "0".         │
           │           │                    │                          │
           │           │                    │ Note that this setting   │
           │           │                    │ is _not_ influenced by the │
           │           │                    │ _User=_ setting            │
           │           │                    │ configurable in the      │
           │           │                    │ [Service] section of the │
           │           │                    │ service unit.            │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%v"      │ Kernel release     │ Identical to **uname -r** │
           │           │                    │ output.                  │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%V"      │ Directory for      │ This is either /var/tmp  │
           │           │ larger and         │ or the path "$TMPDIR",   │
           │           │ persistent         │ "$TEMP" or "$TMP" are    │
           │           │ temporary files    │ set to. (Note that the   │
           │           │                    │ directory may be         │
           │           │                    │ specified without a      │
           │           │                    │ trailing slash.)         │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%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.             │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%y"      │ The path to the    │ This is the path where   │
           │           │ fragment           │ the main part of the     │
           │           │                    │ unit file is located.    │
           │           │                    │ For linked unit files,   │
           │           │                    │ the real path outside of │
           │           │                    │ the unit search          │
           │           │                    │ directories is used. For │
           │           │                    │ units that do not have a │
           │           │                    │ fragment file, this      │
           │           │                    │ specifier will raise an  │
           │           │                    │ error.                   │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%Y"      │ The directory of   │ This is the directory    │
           │           │ the fragment       │ part of "%y".            │
           ├───────────┼────────────────────┼──────────────────────────┤
           │ "%%"      │ Single percent     │ Use "%%" in place of "%" │
           │           │ sign               │ to specify a single      │
           │           │                    │ percent sign.            │
           └───────────┴────────────────────┴──────────────────────────┘
    


## EXAMPLES



           **Example 1. Allowing units to be enabled**
    
           The following snippet (highlighted) allows a unit (e.g.
           foo.service) to be enabled via **systemctl enable** :
    
               [Unit]
               Description=Foo
    
               [Service]
               ExecStart=/usr/sbin/foo-daemon
    
               _[Install]_
               _WantedBy=multi-user.target_
    
           After running **systemctl enable** , a symlink
           /etc/systemd/system/multi-user.target.wants/foo.service linking to
           the actual unit will be created. It tells systemd to pull in the
           unit when starting multi-user.target. The inverse **systemctl**
           **disable** will remove that symlink again.
    
           **Example 2. Overriding vendor settings**
    
           There are two methods of overriding vendor settings in unit files:
           copying the unit file from /usr/lib/systemd/system to
           /etc/systemd/system and modifying the chosen settings.
           Alternatively, one can create a directory named _unit_.d/ within
           /etc/systemd/system and place a drop-in file _name_.conf there that
           only changes the specific settings one is interested in. Note that
           multiple such drop-in files are read if present, processed in
           lexicographic order of their filename.
    
           The advantage of the first method is that one easily overrides the
           complete unit, the vendor unit is not parsed at all anymore. It
           has the disadvantage that improvements to the unit file by the
           vendor are not automatically incorporated on updates.
    
           The advantage of the second method is that one only overrides the
           settings one specifically wants, where updates to the unit by the
           vendor automatically apply. This has the disadvantage that some
           future updates by the vendor might be incompatible with the local
           changes.
    
           This also applies for user instances of systemd, but with
           different locations for the unit files. See the section on unit
           load paths for further details.
    
           Suppose there is a vendor-supplied unit
           /usr/lib/systemd/system/httpd.service with the following contents:
    
               [Unit]
               Description=Some HTTP Server
               After=remote-fs.target sqldb.service
               Requires=sqldb.service
               AssertPathExists=/srv/webserver
    
               [Service]
               Type=notify
               ExecStart=/usr/sbin/some-fancy-httpd-server
               Nice=5
    
               [Install]
               WantedBy=multi-user.target
    
           Now one wants to change some settings as an administrator:
           firstly, in the local setup, /srv/webserver might not exist,
           because the HTTP server is configured to use /srv/www instead.
           Secondly, the local configuration makes the HTTP server also
           depend on a memory cache service, memcached.service, that should
           be pulled in (_Requires=_) and also be ordered appropriately
           (_After=_). Thirdly, in order to harden the service a bit more, the
           administrator would like to set the _PrivateTmp=_ setting (see
           systemd.exec(5) for details). And lastly, the administrator would
           like to reset the niceness of the service to its default value of
           0.
    
           The first possibility is to copy the unit file to
           /etc/systemd/system/httpd.service and change the chosen settings:
    
               [Unit]
               Description=Some HTTP Server
               After=remote-fs.target sqldb.service _memcached.service_
               Requires=sqldb.service _memcached.service_
               AssertPathExists=_/srv/www_
    
               [Service]
               Type=notify
               ExecStart=/usr/sbin/some-fancy-httpd-server
               _Nice=0_
               _PrivateTmp=yes_
    
               [Install]
               WantedBy=multi-user.target
    
           Alternatively, the administrator could create a drop-in file
           /etc/systemd/system/httpd.service.d/local.conf with the following
           contents:
    
               [Unit]
               After=memcached.service
               Requires=memcached.service
               # Reset all assertions and then re-add the condition we want
               AssertPathExists=
               AssertPathExists=/srv/www
    
               [Service]
               Nice=0
               PrivateTmp=yes
    
           Note that for drop-in files, if one wants to remove entries from a
           setting that is parsed as a list (and is not a dependency), such
           as _AssertPathExists=_ (or e.g.  _ExecStart=_ in service units), one
           needs to first clear the list before re-adding all entries except
           the one that is to be removed. Dependencies (_After=_ , etc.) cannot
           be reset to an empty list, so dependencies can only be added in
           drop-ins. If you want to remove dependencies, you have to override
           the entire unit.
    
           **Example 3. Top level drop-ins with template units**
    
           Top level per-type drop-ins can be used to change some aspect of
           all units of a particular type. For example, by creating the
           /etc/systemd/system/service.d/ directory with a drop-in file, the
           contents of the drop-in file can be applied to all service units.
           We can take this further by having the top-level drop-in
           instantiate a secondary helper unit. Consider for example the
           following set of units and drop-in files where we install an
           _OnFailure=_ dependency for all service units.
    
           /etc/systemd/system/failure-handler@.service:
    
               [Unit]
               Description=My Failure Handler For %i
    
               [Service]
               Type=oneshot
               # Perform some special action for when %i exits unexpectedly.
               ExecStart=/usr/sbin/myfailurehandler %i
    
           We can then add an instance of failure-handler@.service as an
           _OnFailure=_ dependency for all service units.
    
           /etc/systemd/system/service.d/10-all.conf:
    
               [Unit]
               OnFailure=failure-handler@%N.service
    
           Now, after running **systemctl daemon-reload** all services will have
           acquired an _OnFailure=_ dependency on failure-handler@%N.service.
           The template instance units will also have gained the dependency
           which results in the creation of a recursive dependency chain.
           systemd will try to detect these recursive dependency chains where
           a template unit directly and recursively depends on itself and
           will remove such dependencies automatically if it finds them. If
           systemd does not detect the recursive dependency chain, we can
           break the chain ourselves by disabling the drop-in for the
           template instance units via a symlink to /dev/null:
    
               **mkdir /etc/systemd/system/failure-handler@.service.d/**
               **ln -s /dev/null /etc/systemd/system/failure-handler@.service.d/10-all.conf**
               **systemctl daemon-reload**
    
           This ensures that if a failure-handler@.service instance fails it
           will not trigger an instance named
           failure-handler@failure-handler.service.
    


## NOTES



            1. Interface Portability and Stability Promise
               https://systemd.io/PORTABILITY_AND_STABILITY/
    
            2. 💣💥🧨💥💥💣 Please note that those configuration files must
               be available at all times. If /usr/local/ is a separate
               partition, it may not be available during early boot, and must
               not be used for configuration.
    
            3. systemd and Storage Daemons for the Root File System
               https://systemd.io/ROOT_STORAGE_DAEMONS
    
            4. System and Service Credentials
               https://systemd.io/CREDENTIALS
    
            5. PSI (Pressure Stall Information)
               https://docs.kernel.org/accounting/psi.html
    


* * *