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SYSTEMD.RESOURCE-CONTROL(5) | systemd.resource-control | SYSTEMD.RESOURCE-CONTROL(5) |
NAME¶
systemd.resource-control - Resource control unit settingsSYNOPSIS¶
slice.slice, scope.scope, service.service, socket.socket, mount.mount, swap.swapDESCRIPTION¶
Unit configuration files for services, slices, scopes, sockets, mount points, and swap devices share a subset of configuration options for resource control of spawned processes. Internally, this relies on the Control Groups kernel concept for organizing processes in a hierarchical tree of named groups for the purpose of resource management. This man page lists the configuration options shared by those six unit types. See systemd.unit(5) for the common options of all unit configuration files, and systemd.slice(5), systemd.scope(5), systemd.service(5), systemd.socket(5), systemd.mount(5), and systemd.swap(5) for more information on the specific unit configuration files. The resource control configuration options are configured in the [Slice], [Scope], [Service], [Socket], [Mount], or [Swap] sections, depending on the unit type. See the New Control Group Interfaces[1] for an introduction on how to make use of resource control APIs from programs.AUTOMATIC DEPENDENCIES¶
Units with the Slice= setting set get automatic Requires= and After= dependencies on the specified slice unit.UNIFIED AND LEGACY CONTROL GROUP HIERARCHIES¶
Unified control group hierarchy is the new version of kernel control group interface. Depending on the resource type, there are differences in resource control capabilities. Also, because of interface changes, some resource types have a separate set of options on the unified hierarchy. IOIO prefixed settings are superset of and replace
BlockIO prefixed ones. On unified hierarchy, IO resource control also
applies to buffered writes.
To ease the transition, there is best-effort translation between the two
versions of settings. If all settings of a unit for a given resource type are
for the other hierarchy type, the settings are translated and applied. If
there are any valid settings for the hierarchy in use, all translations are
disabled for the resource type. Mixing the two types of settings on a unit can
lead to confusing results.
OPTIONS¶
Units of the types listed above can have settings for resource control configuration: CPUAccounting=Turn on CPU usage accounting for this unit. Takes a
boolean argument. Note that turning on CPU accounting for one unit will also
implicitly turn it on for all units contained in the same slice and for all
its parent slices and the units contained therein. The system default for this
setting may be controlled with DefaultCPUAccounting= in
systemd-system.conf(5).
CPUShares=weight,
StartupCPUShares=weight
Assign the specified CPU time share weight to the
processes executed. These options take an integer value and control the
"cpu.shares" control group attribute. The allowed range is 2 to
262144. Defaults to 1024. For details about this control group attribute, see
sched-design-CFS.txt[2]. The available CPU time is split up among all
units within one slice relative to their CPU time share weight.
While StartupCPUShares= only applies to the startup phase of the system,
CPUShares= applies to normal runtime of the system, and if the former
is not set also to the startup phase. Using StartupCPUShares= allows
prioritizing specific services at boot-up differently than during normal
runtime.
These options imply "CPUAccounting=true".
CPUQuota=
Assign the specified CPU time quota to the processes
executed. Takes a percentage value, suffixed with "%". The
percentage specifies how much CPU time the unit shall get at maximum, relative
to the total CPU time available on one CPU. Use values > 100% for allotting
CPU time on more than one CPU. This controls the "cpu.cfs_quota_us"
control group attribute. For details about this control group attribute, see
sched-design-CFS.txt[2].
Example: CPUQuota=20% ensures that the executed processes will never get
more than 20% CPU time on one CPU.
Implies "CPUAccounting=true".
MemoryAccounting=
Turn on process and kernel memory accounting for this
unit. Takes a boolean argument. Note that turning on memory accounting for one
unit will also implicitly turn it on for all units contained in the same slice
and for all its parent slices and the units contained therein. The system
default for this setting may be controlled with
DefaultMemoryAccounting= in systemd-system.conf(5).
MemoryLimit=bytes
Specify the limit on maximum memory usage of the executed
processes. The limit specifies how much process and kernel memory can be used
by tasks in this unit. Takes a memory size in bytes. If the value is suffixed
with K, M, G or T, the specified memory size is parsed as Kilobytes,
Megabytes, Gigabytes, or Terabytes (with the base 1024), respectively. If
assigned the special value "infinity", no memory limit is applied.
This controls the "memory.limit_in_bytes" control group attribute.
For details about this control group attribute, see memory.txt[3].
Implies "MemoryAccounting=true".
TasksAccounting=
Turn on task accounting for this unit. Takes a boolean
argument. If enabled, the system manager will keep track of the number of
tasks in the unit. The number of tasks accounted this way includes both kernel
threads and userspace processes, with each thread counting individually. Note
that turning on tasks accounting for one unit will also implicitly turn it on
for all units contained in the same slice and for all its parent slices and
the units contained therein. The system default for this setting may be
controlled with DefaultTasksAccounting= in
systemd-system.conf(5).
TasksMax=N
Specify the maximum number of tasks that may be created
in the unit. This ensures that the number of tasks accounted for the unit (see
above) stays below a specific limit. If assigned the special value
"infinity", no tasks limit is applied. This controls the
"pids.max" control group attribute. For details about this control
group attribute, see pids.txt[4].
Implies "TasksAccounting=true". The system default for this setting
may be controlled with DefaultTasksMax= in
systemd-system.conf(5).
IOAccounting=
Turn on Block I/O accounting for this unit, if the
unified control group hierarchy is used on the system. Takes a boolean
argument. Note that turning on block I/O accounting for one unit will also
implicitly turn it on for all units contained in the same slice and all for
its parent slices and the units contained therein. The system default for this
setting may be controlled with DefaultIOAccounting= in
systemd-system.conf(5).
This setting is supported only if the unified control group hierarchy is used.
Use BlockIOAccounting= on systems using the legacy control group
hierarchy.
IOWeight=weight,
StartupIOWeight=weight
Set the default overall block I/O weight for the executed
processes, if the unified control group hierarchy is used on the system. Takes
a single weight value (between 1 and 10000) to set the default block I/O
weight. This controls the "io.weight" control group attribute, which
defaults to 100. For details about this control group attribute, see
cgroup-v2.txt[5]. The available I/O bandwidth is split up among all
units within one slice relative to their block I/O weight.
While StartupIOWeight= only applies to the startup phase of the system,
IOWeight= applies to the later runtime of the system, and if the former
is not set also to the startup phase. This allows prioritizing specific
services at boot-up differently than during runtime.
Implies "IOAccounting=true".
This setting is supported only if the unified control group hierarchy is used.
Use BlockIOWeight= and StartupBlockIOWeight= on systems using
the legacy control group hierarchy.
IODeviceWeight=device weight
Set the per-device overall block I/O weight for the
executed processes, if the unified control group hierarchy is used on the
system. Takes a space-separated pair of a file path and a weight value to
specify the device specific weight value, between 1 and 10000. (Example:
"/dev/sda 1000"). The file path may be specified as path to a block
device node or as any other file, in which case the backing block device of
the file system of the file is determined. This controls the
"io.weight" control group attribute, which defaults to 100. Use this
option multiple times to set weights for multiple devices. For details about
this control group attribute, see cgroup-v2.txt[5].
Implies "IOAccounting=true".
This setting is supported only if the unified control group hierarchy is used.
Use BlockIODeviceWeight= on systems using the legacy control group
hierarchy.
IOReadBandwidthMax=device bytes,
IOWriteBandwidthMax= device bytes
Set the per-device overall block I/O bandwidth maximum
limit for the executed processes, if the unified control group hierarchy is
used on the system. This limit is not work-conserving and the executed
processes are not allowed to use more even if the device has idle capacity.
Takes a space-separated pair of a file path and a bandwidth value (in bytes
per second) to specify the device specific bandwidth. The file path may be a
path to a block device node, or as any other file in which case the backing
block device of the file system of the file is used. If the bandwidth is
suffixed with K, M, G, or T, the specified bandwidth is parsed as Kilobytes,
Megabytes, Gigabytes, or Terabytes, respectively, to the base of 1000.
(Example: "/dev/disk/by-path/pci-0000:00:1f.2-scsi-0:0:0:0 5M").
This controls the "io.max" control group attributes. Use this option
multiple times to set bandwidth limits for multiple devices. For details about
this control group attribute, see cgroup-v2.txt[5].
Implies "IOAccounting=true".
This setting is supported only if the unified control group hierarchy is used.
Use BlockIOAccounting= on systems using the legacy control group
hierarchy.
IOReadIOPSMax=device IOPS,
IOWriteIOPSMax= device IOPS
Set the per-device overall block I/O IOs-Per-Second
maximum limit for the executed processes, if the unified control group
hierarchy is used on the system. This limit is not work-conserving and the
executed processes are not allowed to use more even if the device has idle
capacity. Takes a space-separated pair of a file path and an IOPS value to
specify the device specific IOPS. The file path may be a path to a block
device node, or as any other file in which case the backing block device of
the file system of the file is used. If the IOPS is suffixed with K, M, G, or
T, the specified IOPS is parsed as KiloIOPS, MegaIOPS, GigaIOPS, or TeraIOPS,
respectively, to the base of 1000. (Example:
"/dev/disk/by-path/pci-0000:00:1f.2-scsi-0:0:0:0 1K"). This controls
the "io.max" control group attributes. Use this option multiple
times to set IOPS limits for multiple devices. For details about this control
group attribute, see cgroup-v2.txt[5].
Implies "IOAccounting=true".
This setting is supported only if the unified control group hierarchy is
used.
BlockIOAccounting=
Turn on Block I/O accounting for this unit, if the legacy
control group hierarchy is used on the system. Takes a boolean argument. Note
that turning on block I/O accounting for one unit will also implicitly turn it
on for all units contained in the same slice and all for its parent slices and
the units contained therein. The system default for this setting may be
controlled with DefaultBlockIOAccounting= in
systemd-system.conf(5).
This setting is supported only if the legacy control group hierarchy is used.
Use IOAccounting= on systems using the unified control group
hierarchy.
BlockIOWeight=weight,
StartupBlockIOWeight=weight
Set the default overall block I/O weight for the executed
processes, if the legacy control group hierarchy is used on the system. Takes
a single weight value (between 10 and 1000) to set the default block I/O
weight. This controls the "blkio.weight" control group attribute,
which defaults to 500. For details about this control group attribute, see
blkio-controller.txt[6]. The available I/O bandwidth is split up among
all units within one slice relative to their block I/O weight.
While StartupBlockIOWeight= only applies to the startup phase of the
system, BlockIOWeight= applies to the later runtime of the system, and
if the former is not set also to the startup phase. This allows prioritizing
specific services at boot-up differently than during runtime.
Implies "BlockIOAccounting=true".
This setting is supported only if the legacy control group hierarchy is used.
Use IOWeight= and StartupIOWeight= on systems using the unified
control group hierarchy.
BlockIODeviceWeight=device weight
Set the per-device overall block I/O weight for the
executed processes, if the legacy control group hierarchy is used on the
system. Takes a space-separated pair of a file path and a weight value to
specify the device specific weight value, between 10 and 1000. (Example:
"/dev/sda 500"). The file path may be specified as path to a block
device node or as any other file, in which case the backing block device of
the file system of the file is determined. This controls the
"blkio.weight_device" control group attribute, which defaults to
1000. Use this option multiple times to set weights for multiple devices. For
details about this control group attribute, see
blkio-controller.txt[6].
Implies "BlockIOAccounting=true".
This setting is supported only if the legacy control group hierarchy is used.
Use IODeviceWeight= on systems using the unified control group
hierarchy.
BlockIOReadBandwidth=device bytes,
BlockIOWriteBandwidth= device bytes
Set the per-device overall block I/O bandwidth limit for
the executed processes, if the legacy control group hierarchy is used on the
system. Takes a space-separated pair of a file path and a bandwidth value (in
bytes per second) to specify the device specific bandwidth. The file path may
be a path to a block device node, or as any other file in which case the
backing block device of the file system of the file is used. If the bandwidth
is suffixed with K, M, G, or T, the specified bandwidth is parsed as
Kilobytes, Megabytes, Gigabytes, or Terabytes, respectively, to the base of
1000. (Example: "/dev/disk/by-path/pci-0000:00:1f.2-scsi-0:0:0:0
5M"). This controls the "blkio.throttle.read_bps_device" and
"blkio.throttle.write_bps_device" control group attributes. Use this
option multiple times to set bandwidth limits for multiple devices. For
details about these control group attributes, see
blkio-controller.txt[6].
Implies "BlockIOAccounting=true".
This setting is supported only if the legacy control group hierarchy is used.
Use IOReadBandwidthMax= and IOWriteBandwidthMax= on systems
using the unified control group hierarchy.
DeviceAllow=
Control access to specific device nodes by the executed
processes. Takes two space-separated strings: a device node specifier followed
by a combination of r, w, m to control reading,
writing, or creation of the specific device node(s) by the unit
(mknod), respectively. This controls the "devices.allow" and
"devices.deny" control group attributes. For details about these
control group attributes, see devices.txt[7].
The device node specifier is either a path to a device node in the file system,
starting with /dev/, or a string starting with either "char-" or
"block-" followed by a device group name, as listed in
/proc/devices. The latter is useful to whitelist all current and future
devices belonging to a specific device group at once. The device group is
matched according to file name globbing rules, you may hence use the
"*" and "?" wildcards. Examples: /dev/sda5 is a path to a
device node, referring to an ATA or SCSI block device. "char-pts"
and "char-alsa" are specifiers for all pseudo TTYs and all ALSA
sound devices, respectively. "char-cpu/*" is a specifier matching
all CPU related device groups.
DevicePolicy=auto|closed|strict
Control the policy for allowing device access:
strict
Slice=
means to only allow types of access that are explicitly
specified.
closed
in addition, allows access to standard pseudo devices
including /dev/null, /dev/zero, /dev/full, /dev/random, and
/dev/urandom.
auto
in addition, allows access to all devices if no explicit
DeviceAllow= is present. This is the default.
The name of the slice unit to place the unit in. Defaults
to system.slice for all non-instantiated units of all unit types (except for
slice units themselves see below). Instance units are by default placed in a
subslice of system.slice that is named after the template name.
This option may be used to arrange systemd units in a hierarchy of slices each
of which might have resource settings applied.
For units of type slice, the only accepted value for this setting is the parent
slice. Since the name of a slice unit implies the parent slice, it is hence
redundant to ever set this parameter directly for slice units.
Special care should be taken when relying on the default slice assignment in
templated service units that have DefaultDependencies=no set, see
systemd.service(5), section "Automatic Dependencies" for
details.
Delegate=
Turns on delegation of further resource control
partitioning to processes of the unit. For unprivileged services (i.e. those
using the User= setting), this allows processes to create a
subhierarchy beneath its control group path. For privileged services and
scopes, this ensures the processes will have all control group controllers
enabled.
SEE ALSO¶
systemd(1), systemd.unit(5), systemd.service(5), systemd.slice(5), systemd.scope(5), systemd.socket(5), systemd.mount(5), systemd.swap(5), systemd.directives(7), systemd.special(7), The documentation for control groups and specific controllers in the Linux kernel: cgroups.txt[8], cpuacct.txt[9], memory.txt[3], blkio-controller.txt[6].NOTES¶
- 1.
- New Control Group Interfaces
- 2.
- sched-design-CFS.txt
- 3.
- memory.txt
- 4.
- pids.txt
- 5.
- cgroup-v2.txt
- 6.
- blkio-controller.txt
- 7.
- devices.txt
- 8.
- cgroups.txt
- 9.
- cpuacct.txt
systemd 230 |