- <varlistentry>
- <term><varname>ControlGroup=</varname></term>
-
- <listitem><para>Controls the control
- groups the executed processes shall be
- made members of. Takes a
- space-separated list of cgroup
- identifiers. A cgroup identifier is
- formatted like
- <filename>cpu:/foo/bar</filename>,
- where "cpu" indicates the kernel
- control group controller used, and
- <filename>/foo/bar</filename> is the
- control group path. The controller
- name and ":" may be omitted in which
- case the named systemd control group
- hierarchy is implied. Alternatively,
- the path and ":" may be omitted, in
- which case the default control group
- path for this unit is implied.</para>
-
- <para>This option may be used to place
- executed processes in arbitrary groups
- in arbitrary hierarchies -- which may
- then be externally configured with
- additional execution limits. By
- default systemd will place all
- executed processes in separate
- per-unit control groups (named after
- the unit) in the systemd named
- hierarchy. This option is primarily
- intended to place executed processes
- in specific paths in specific kernel
- controller hierarchies. It is not
- recommended to manipulate the service
- control group path in the systemd
- named hierarchy. For details about
- control groups see <ulink
- url="http://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink>.</para>
-
- <para>This option may appear more than
- once, in which case the list of
- control group assignments is
- merged. If the same hierarchy gets two
- different paths assigned only the
- later setting will take effect. If the
- empty string is assigned to this
- option the list of control group
- assignments is reset, all previous
- assignments will have no
- effect.</para>
-
- <para>Note that the list of control
- group assignments of a unit is
- extended implicitly based on the
- settings of
- <varname>DefaultControllers=</varname>
- of
- <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
- but a unit's
- <varname>ControlGroup=</varname>
- setting for a specific controller
- takes precedence.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>ControlGroupModify=</varname></term>
- <listitem><para>Takes a boolean
- argument. If true, the control groups
- created for this unit will be owned by
- the user specified with
- <varname>User=</varname> (and the
- appropriate group), and he/she can create
- subgroups as well as add processes to
- the group.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>ControlGroupPersistent=</varname></term>
- <listitem><para>Takes a boolean
- argument. If true, the control groups
- created for this unit will be marked
- to be persistent, i.e. systemd will
- not remove them when stopping the
- unit. The default is false, meaning
- that the control groups will be
- removed when the unit is stopped. For
- details about the semantics of this
- logic see <ulink
- url="http://www.freedesktop.org/wiki/Software/systemd/PaxControlGroups">PaxControlGroups</ulink>.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>ControlGroupAttribute=</varname></term>
-
- <listitem><para>Set a specific control
- group attribute for executed
- processes, and (if needed) add the
- executed processes to a cgroup in the
- hierarchy of the controller the
- attribute belongs to. Takes two
- space-separated arguments: the
- attribute name (syntax is
- <literal>cpu.shares</literal> where
- <literal>cpu</literal> refers to a
- specific controller and
- <literal>shares</literal> to the
- attribute name), and the attribute
- value. Example:
- <literal>ControlGroupAttribute=cpu.shares
- 512</literal>. If this option is used
- for an attribute that belongs to a
- kernel controller hierarchy the unit
- is not already configured to be added
- to (for example via the
- <literal>ControlGroup=</literal>
- option) then the unit will be added to
- the controller and the default unit
- cgroup path is implied. Thus, using
- <varname>ControlGroupAttribute=</varname>
- is in most cases sufficient to make
- use of control group enforcements,
- explicit
- <varname>ControlGroup=</varname> are
- only necessary in case the implied
- default control group path for a
- service is not desirable. For details
- about control group attributes see
- <ulink
- url="http://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink>. This
- option may appear more than once, in
- order to set multiple control group
- attributes. If this option is used
- multiple times for the same cgroup
- attribute only the later setting takes
- effect. If the empty string is
- assigned to this option the list of
- attributes is reset, all previous
- cgroup attribute settings have no
- effect, including those done with
- <varname>CPUShares=</varname>,
- <varname>MemoryLimit=</varname>,
- <varname>MemorySoftLimit</varname>,
- <varname>DeviceAllow=</varname>,
- <varname>DeviceDeny=</varname>,
- <varname>BlockIOWeight=</varname>,
- <varname>BlockIOReadBandwidth=</varname>,
- <varname>BlockIOWriteBandwidth=</varname>.
- </para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>CPUShares=</varname></term>
-
- <listitem><para>Assign the specified
- overall CPU time shares to the
- processes executed. Takes an integer
- value. This controls the
- <literal>cpu.shares</literal> control
- group attribute, which defaults to
- 1024. For details about this control
- group attribute see <ulink
- url="http://www.kernel.org/doc/Documentation/scheduler/sched-design-CFS.txt">sched-design-CFS.txt</ulink>.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>MemoryLimit=</varname></term>
- <term><varname>MemorySoftLimit=</varname></term>
-
- <listitem><para>Limit the overall memory usage
- of the executed processes to a certain
- size. 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 (to the base
- 1024), respectively. This controls the
- <literal>memory.limit_in_bytes</literal>
- and
- <literal>memory.soft_limit_in_bytes</literal>
- control group attributes. For details
- about these control group attributes
- see <ulink
- url="http://www.kernel.org/doc/Documentation/cgroups/memory.txt">memory.txt</ulink>.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>DeviceAllow=</varname></term>
- <term><varname>DeviceDeny=</varname></term>
-
- <listitem><para>Control access to
- specific device nodes by the executed processes. Takes two
- space separated strings: a device node
- path (such as
- <filename>/dev/null</filename>)
- followed by a combination of r, w, m
- to control reading, writing, or
- creating of the specific device node
- by the unit, respectively. This controls the
- <literal>devices.allow</literal>
- and
- <literal>devices.deny</literal>
- control group attributes. For details
- about these control group attributes
- see <ulink
- url="http://www.kernel.org/doc/Documentation/cgroups/devices.txt">devices.txt</ulink>.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>BlockIOWeight=</varname></term>
-
- <listitem><para>Set the default or
- per-device overall block IO weight
- value for the executed
- processes. Takes either a single
- weight value (between 10 and 1000) to
- set the default block IO weight, or a
- space separated pair of a file path
- and a weight value to specify the
- device specific weight value (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
- <literal>blkio.weight</literal> and
- <literal>blkio.weight_device</literal>
- control group attributes, which
- default to 1000. Use this option
- multiple times to set weights for
- multiple devices. For details about
- these control group attributes see
- <ulink
- url="http://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>BlockIOReadBandwidth=</varname></term>
- <term><varname>BlockIOWriteBandwidth=</varname></term>
-
- <listitem><para>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
- 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.
- If the bandwidth is suffixed with K, M,
- G, or T the specified bandwidth is
- parsed as Kilobytes, Megabytes,
- Gigabytes, or Terabytes, respectively (Example:
- "/dev/disk/by-path/pci-0000:00:1f.2-scsi-0:0:0:0
- 5M"). This controls the
- <literal>blkio.read_bps_device</literal>
- and
- <literal>blkio.write_bps_device</literal>
- control group attributes. Use this
- option multiple times to set bandwidth
- limits for multiple devices. For
- details about these control group
- attributes see <ulink
- url="http://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.</para></listitem>
- </varlistentry>
-