конфигурация установки (Mount unit configuration)
Имя (Name)
systemd.mount - Mount unit configuration
Синопсис (Synopsis)
mount.mount
Описание (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
The systemd-mount(1) command allows creating .mount and
.automount units dynamically and transiently from the command
line.
Автоматические зависимости (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 (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/.
Параметры (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.
Смотри также (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)
Примечание (Note)
1. API File Systems
https://www.freedesktop.org/wiki/Software/systemd/APIFileSystems
