SYSTEMD.RESOURCE-CONTROL(5)          systemd.resource-control         SYSTEMD.RESOURCE-CONTROL(5)



NAME
       systemd.resource-control - Resource control unit settings

SYNOPSIS
       slice.slice, scope.scope, service.service, socket.socket, mount.mount, swap.swap

DESCRIPTION
       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
       hierarchial 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.

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 might 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 maybe controlled with
           DefaultCPUAccounting= in systemd-system.conf(5).

       CPUShares=weight, StartupCPUShares=weight
           Assign the specified CPU time share weight to the processes executed. Those options
           take an integer value and control the "cpu.shares" control group attribute, which
           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 priorizing specific services at boot-up
           differently than during normal runtime.

           Those 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 alloting 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: CPUShares=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 might also implicitly turn it on
           for all its parent slices. The system default for this setting maybe 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. This controls the "memory.limit_in_bytes" control group
           attribute. For details about this control group attribute, see memory.txt[3].

           Implies "MemoryAccounting=true".

       BlockIOAccounting=
           Turn on Block IO accounting for this unit. Takes a boolean argument. Note that turning
           on block IO accounting for one unit might 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 maybe controlled with
           DefaultBlockIOAccounting= in systemd-system.conf(5).

       BlockIOWeight=weight, StartupBlockIOWeight=weight
           Set the default overall block IO weight for the executed processes. Takes a single
           weight value (between 10 and 1000) to set the default block IO weight. This controls
           the "blkio.weight" control group attribute, which defaults to 1000. For details about
           this control group attribute, see blkio-controller.txt[4]. The available IO bandwidth
           is split up among all units within one slice relative to their block IO 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 priorizing specific services at boot-up
           differently than during runtime.

           Implies "BlockIOAccounting=true".

       BlockIODeviceWeight=device weight
           Set the per-device overall block IO weight for the executed processes. 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[4].

           Implies "BlockIOAccounting=true".

       BlockIOReadBandwidth=device bytes, BlockIOWriteBandwidth=device bytes
           Set the per-device overall block IO bandwidth limit for the executed processes. 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.read_bps_device" and "blkio.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[4].

           Implies "BlockIOAccounting=true".

       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[5].

           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
               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.

       Slice=
           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.

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[6], cpuacct.txt[7], memory.txt[3], blkio-controller.txt[4].

NOTES
        1. New Control Group Interfaces
           http://www.freedesktop.org/wiki/Software/systemd/ControlGroupInterface/

        2. sched-design-CFS.txt
           https://www.kernel.org/doc/Documentation/scheduler/sched-design-CFS.txt

        3. memory.txt
           https://www.kernel.org/doc/Documentation/cgroup-v1/memory.txt

        4. blkio-controller.txt
           https://www.kernel.org/doc/Documentation/cgroup-v1/blkio-controller.txt

        5. devices.txt
           https://www.kernel.org/doc/Documentation/cgroup-v1/devices.txt

        6. cgroups.txt
           https://www.kernel.org/doc/Documentation/cgroup-v1/cgroups.txt

        7. cpuacct.txt
           https://www.kernel.org/doc/Documentation/cgroup-v1/cpuacct.txt



systemd 215                                                           SYSTEMD.RESOURCE-CONTROL(5)