systemd.mount

SYSTEMD.MOUNT(5)                  systemd.mount                 SYSTEMD.MOUNT(5)



NAME
       systemd.mount - Mount unit configuration

SYNOPSIS
       mount.mount

DESCRIPTION
       A unit configuration file whose name ends in ".mount" encodes information
       about a file system mount point controlled and supervised by systemd.

       This man page lists the configuration options specific to this unit type.
       See systemd.unit(5) for the common options of all unit configuration
       files. The common configuration items are configured in the generic
       [Unit] and [Install] sections. The mount specific configuration options
       are configured in the [Mount] section.

       Additional options are listed in systemd.exec(5), which define the
       execution environment the mount(8) program is executed in, and in
       systemd.kill(5), which define the way the processes are terminated, and
       in systemd.resource-control(5), which configure resource control settings
       for the processes of the service.

       Note that the options User= and Group= are not useful for mount units.
       systemd passes two parameters to mount(8); the values of What= and
       Where=. When invoked in this way, mount(8) does not read any options from
       /etc/fstab, and must be run as UID 0.

       Mount units must be named after the mount point directories they control.
       Example: the mount point /home/lennart must be configured in a unit file
       home-lennart.mount. For details about the escaping logic used to convert
       a file system path to a unit name, see systemd.unit(5). Note that mount
       units cannot be templated, nor is possible to add multiple names to a
       mount unit by creating additional symlinks to it.

       Optionally, a mount unit may be accompanied by an automount unit, to
       allow on-demand or parallelized mounting. See systemd.automount(5).

       Mount points created at runtime (independently of unit files or
       /etc/fstab) will be monitored by systemd and appear like any other mount
       unit in systemd. See /proc/self/mountinfo description in proc(5).

       Some file systems have special semantics as API file systems for
       kernel-to-userspace and userspace-to-userspace interfaces. Some of them
       may not be changed via mount units, and cannot be disabled. For a longer
       discussion see API File Systems[1].

       The systemd-mount(1) command allows creating .mount and .automount units
       dynamically and transiently from the command line.

AUTOMATIC DEPENDENCIES
   Implicit Dependencies
       The following dependencies are implicitly added:

       •   If a mount unit is beneath another mount unit in the file system
           hierarchy, both a requirement dependency and an ordering dependency
           between both units are created automatically.

       •   Block device backed file systems automatically gain BindsTo= and
           After= type dependencies on the device unit encapsulating the block
           device (see below).

       •   If traditional file system quota is enabled for a mount unit,
           automatic Wants= and Before= dependencies on
           systemd-quotacheck.service and quotaon.service are added.

       •   Additional implicit dependencies may be added as result of execution
           and resource control parameters as documented in systemd.exec(5) and
           systemd.resource-control(5).

   Default Dependencies
       The following dependencies are added unless DefaultDependencies=no is
       set:

       •   All mount units acquire automatic Before= and Conflicts= on
           umount.target in order to be stopped during shutdown.

       •   Mount units referring to local file systems automatically gain an
           After= dependency on local-fs-pre.target, and a Before= dependency on
           local-fs.target unless nofail mount option is set.

       •   Network mount units automatically acquire After= dependencies on
           remote-fs-pre.target, network.target and network-online.target, and
           gain a Before= dependency on remote-fs.target unless nofail mount
           option is set. Towards the latter a Wants= unit is added as well.

       Mount units referring to local and network file systems are distinguished
       by their file system type specification. In some cases this is not
       sufficient (for example network block device based mounts, such as
       iSCSI), in which case _netdev may be added to the mount option string of
       the unit, which forces systemd to consider the mount unit a network
       mount.

FSTAB
       Mount units may either be configured via unit files, or via /etc/fstab
       (see fstab(5) for details). Mounts listed in /etc/fstab will be converted
       into native units dynamically at boot and when the configuration of the
       system manager is reloaded. In general, configuring mount points through
       /etc/fstab is the preferred approach. See systemd-fstab-generator(8) for
       details about the conversion.

       The NFS mount option bg for NFS background mounts as documented in nfs(5)
       is detected by systemd-fstab-generator and the options are transformed so
       that systemd fulfills the job-control implications of that option.
       Specifically systemd-fstab-generator acts as though
       "x-systemd.mount-timeout=infinity,retry=10000" was prepended to the
       option list, and "fg,nofail" was appended. Depending on specific
       requirements, it may be appropriate to provide some of these options
       explicitly, or to make use of the "x-systemd.automount" option described
       below instead of using "bg".

       When reading /etc/fstab a few special mount options are understood by
       systemd which influence how dependencies are created for mount points.
       systemd will create a dependency of type Wants= or Requires= (see option
       nofail below), from either local-fs.target or remote-fs.target, depending
       whether the file system is local or remote.

       x-systemd.requires=
           Configures a Requires= and an After= dependency between the created
           mount unit and another systemd unit, such as a device or mount unit.
           The argument should be a unit name, or an absolute path to a device
           node or mount point. This option may be specified more than once.
           This option is particularly useful for mount point declarations that
           need an additional device to be around (such as an external journal
           device for journal file systems) or an additional mount to be in
           place (such as an overlay file system that merges multiple mount
           points). See After= and Requires= in systemd.unit(5) for details.

           Note that this option always applies to the created mount unit only
           regardless whether x-systemd.automount has been specified.

       x-systemd.before=, x-systemd.after=
           In the created mount unit, configures a Before= or After= dependency
           on another systemd unit, such as a mount unit. The argument should be
           a unit name or an absolute path to a mount point. This option may be
           specified more than once. This option is particularly useful for
           mount point declarations with nofail option that are mounted
           asynchronously but need to be mounted before or after some unit
           start, for example, before local-fs.target unit. See Before= and
           After= in systemd.unit(5) for details.

           Note that these options always apply to the created mount unit only
           regardless whether x-systemd.automount has been specified.

       x-systemd.wanted-by=, x-systemd.required-by=
           In the created mount unit, configures a WantedBy= or RequiredBy=
           dependency on another unit. This option may be specified more than
           once. If this is specified, the normal automatic dependencies on the
           created mount unit, e.g., local-fs.target, are not automatically
           created. See WantedBy= and RequiredBy= in systemd.unit(5) for
           details.

       x-systemd.requires-mounts-for=
           Configures a RequiresMountsFor= dependency between the created mount
           unit and other mount units. The argument must be an absolute path.
           This option may be specified more than once. See RequiresMountsFor=
           in systemd.unit(5) for details.

       x-systemd.device-bound
           The block device backed file system will be upgraded to BindsTo=
           dependency. This option is only useful when mounting file systems
           manually with mount(8) as the default dependency in this case is
           Requires=. This option is already implied by entries in /etc/fstab or
           by mount units.

       x-systemd.automount
           An automount unit will be created for the file system. See
           systemd.automount(5) for details.

       x-systemd.idle-timeout=
           Configures the idle timeout of the automount unit. See
           TimeoutIdleSec= in systemd.automount(5) for details.

       x-systemd.device-timeout=
           Configure how long systemd should wait for a device to show up before
           giving up on an entry from /etc/fstab. Specify a time in seconds or
           explicitly append a unit such as "s", "min", "h", "ms".

           Note that this option can only be used in /etc/fstab, and will be
           ignored when part of the Options= setting in a unit file.

       x-systemd.mount-timeout=
           Configure how long systemd should wait for the mount command to
           finish before giving up on an entry from /etc/fstab. Specify a time
           in seconds or explicitly append a unit such as "s", "min", "h", "ms".

           Note that this option can only be used in /etc/fstab, and will be
           ignored when part of the Options= setting in a unit file.

           See TimeoutSec= below for details.

       x-systemd.makefs
           The file system will be initialized on the device. If the device is
           not "empty", i.e. it contains any signature, the operation will be
           skipped. It is hence expected that this option remains set even after
           the device has been initialized.

           Note that this option can only be used in /etc/fstab, and will be
           ignored when part of the Options= setting in a unit file.

           See systemd-makefs@.service(8).

           wipefs(8) may be used to remove any signatures from a block device to
           force x-systemd.makefs to reinitialize the device.

       x-systemd.growfs
           The file system will be grown to occupy the full block device. If the
           file system is already at maximum size, no action will be performed.
           It is hence expected that this option remains set even after the file
           system has been grown. Only certain file system types are supported,
           see systemd-makefs@.service(8) for details.

           Note that this option can only be used in /etc/fstab, and will be
           ignored when part of the Options= setting in a unit file.

       x-systemd.rw-only
           If a mount operation fails to mount the file system read-write, it
           normally tries mounting the file system read-only instead. This
           option disables that behaviour, and causes the mount to fail
           immediately instead. This option is translated into the
           ReadWriteOnly= setting in a unit file.

       _netdev
           Normally the file system type is used to determine if a mount is a
           "network mount", i.e. if it should only be started after the network
           is available. Using this option overrides this detection and
           specifies that the mount requires network.

           Network mount units are ordered between remote-fs-pre.target and
           remote-fs.target, instead of local-fs-pre.target and local-fs.target.
           They also pull in network-online.target and are ordered after it and
           network.target.

       noauto, auto
           With noauto, the mount unit will not be added as a dependency for
           local-fs.target or remote-fs.target. This means that it will not be
           mounted automatically during boot, unless it is pulled in by some
           other unit. The auto option has the opposite meaning and is the
           default. Note that the noauto option has an effect on the mount unit
           itself only — if x-systemd.automount is used (see above), then the
           matching automount unit will still be pulled in by these targets.

       nofail
           With nofail, this mount will be only wanted, not required, by
           local-fs.target or remote-fs.target. Moreover the mount unit is not
           ordered before these target units. This means that the boot will
           continue without waiting for the mount unit and regardless whether
           the mount point can be mounted successfully.

       x-initrd.mount
           An additional filesystem to be mounted in the initramfs. See
           initrd-fs.target description in systemd.special(7).

       If a mount point is configured in both /etc/fstab and a unit file that is
       stored below /usr/, the former will take precedence. If the unit file is
       stored below /etc/, it will take precedence. This means: native unit
       files take precedence over traditional configuration files, but this is
       superseded by the rule that configuration in /etc/ will always take
       precedence over configuration in /usr/.

OPTIONS
       Mount files must include a [Mount] section, which carries information
       about the file system mount points it supervises. A number of options
       that may be used in this section are shared with other unit types. These
       options are documented in systemd.exec(5) and systemd.kill(5). The
       options specific to the [Mount] section of mount units are the following:

       What=
           Takes an absolute path of a device node, file or other resource to
           mount. See mount(8) for details. If this refers to a device node, a
           dependency on the respective device unit is automatically created.
           (See systemd.device(5) for more information.) This option is
           mandatory. Note that the usual specifier expansion is applied to this
           setting, literal percent characters should hence be written as "%%".
           If this mount is a bind mount and the specified path does not exist
           yet it is created as directory.

       Where=
           Takes an absolute path of a file or directory for the mount point; in
           particular, the destination cannot be a symbolic link. If the mount
           point does not exist at the time of mounting, it is created as
           directory. This string must be reflected in the unit filename. (See
           above.) This option is mandatory.

       Type=
           Takes a string for the file system type. See mount(8) for details.
           This setting is optional.

       Options=
           Mount options to use when mounting. This takes a comma-separated list
           of options. This setting is optional. Note that the usual specifier
           expansion is applied to this setting, literal percent characters
           should hence be written as "%%".

       SloppyOptions=
           Takes a boolean argument. If true, parsing of the options specified
           in Options= is relaxed, and unknown mount options are tolerated. This
           corresponds with mount(8)'s -s switch. Defaults to off.

       LazyUnmount=
           Takes a boolean argument. If true, detach the filesystem from the
           filesystem hierarchy at time of the unmount operation, and clean up
           all references to the filesystem as soon as they are not busy
           anymore. This corresponds with umount(8)'s -l switch. Defaults to
           off.

       ReadWriteOnly=
           Takes a boolean argument. If false, a mount point that shall be
           mounted read-write but cannot be mounted so is retried to be mounted
           read-only. If true the operation will fail immediately after the
           read-write mount attempt did not succeed. This corresponds with
           mount(8)'s -w switch. Defaults to off.

       ForceUnmount=
           Takes a boolean argument. If true, force an unmount (in case of an
           unreachable NFS system). This corresponds with umount(8)'s -f switch.
           Defaults to off.

       DirectoryMode=
           Directories of mount points (and any parent directories) are
           automatically created if needed. This option specifies the file
           system access mode used when creating these directories. Takes an
           access mode in octal notation. Defaults to 0755.

       TimeoutSec=
           Configures the time to wait for the mount command to finish. If a
           command does not exit within the configured time, the mount will be
           considered failed and be shut down again. All commands still running
           will be terminated forcibly via SIGTERM, and after another delay of
           this time with SIGKILL. (See KillMode= in systemd.kill(5).) Takes a
           unit-less value in seconds, or a time span value such as "5min 20s".
           Pass 0 to disable the timeout logic. The default value is set from
           DefaultTimeoutStartSec= option in systemd-system.conf(5).

       Check systemd.exec(5) and systemd.kill(5) for more settings.

SEE ALSO
       systemd(1), systemctl(1), systemd-system.conf(5), systemd.unit(5),
       systemd.exec(5), systemd.kill(5), systemd.resource-control(5),
       systemd.service(5), systemd.device(5), proc(5), mount(8), systemd-fstab-
       generator(8), systemd.directives(7), systemd-mount(1)

NOTES
        1. API File Systems
           https://www.freedesktop.org/wiki/Software/systemd/APIFileSystems



systemd 247                                                     SYSTEMD.MOUNT(5)