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.\"***********************************
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cgconfig.conf \- libcgroup configuration file
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.\"***********************************
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is the configuration file used by
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to define control groups, their parameters and also mount points.
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These sections can be in arbitrary order.
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Any line starting with '#' is considered as comment line and is
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<controller> = <path>;
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Name of kernel subsystem. List of subsystems supported by kernel
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merges all subsystems mounted to the same directory (see
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Example 1) and the directory is mounted only once.
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The directory path, where group hierarchy associated to given
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controller, shall be mounted. The directory is created
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automatically on cgconfig service startup if it does not exist and
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is deleted on service shutdown.
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<param name> = <param value>;
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Name of the control group. It can contain only characters, which are
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allowed for directory names.
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The groups form a tree, i.e. a control group can contain zero or more
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subgroups. Subgroups can be specified using '/' delimiter.
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The root control group is always created automatically in all hierarchies
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and it is the base of the group hierarchy. It can be explicitly specified in
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file by using '.' as group name. This can be used e.g. to set its permissions,
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as shown in Example 5.
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When the parent control group of a subgroup is not specified,
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then it is created automatically.
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Permissions of the given control group on mounted filesystem.
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has always permission to do anything with the control group.
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Permissions have the following syntax:
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Name of the user and the group, which owns
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file of the control group. I.e. this user and members of this
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group has write access to the file.
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.B "admin user/group"
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Name of the user and the group, which owns the rest of control group's
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files. These users are allowed to set subsystem
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parameters and create subgroups.
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Permissions are related only to enclosing control group and are not
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inherited by subgroups. If there is no
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section in control group definition,
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is owner of all files.
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Name of the kernel subsystem.
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empty, default kernel parameters will be used in this case. By
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the control group and all its parents are controlled by the specific
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subsystem. One control group can be controlled by multiple subsystems,
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even if the subsystems are mounted to different directories. Each
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control group must be controlled by at least one subsystem, so
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knows, in which hierarchies the control group should be created.
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The parameters of given controller can be modified in following section
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enclosed in brackets.
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Name of the file to set. Each controller can have zero or more
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Value, which should be written to the file when the control group is
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.\"********************************************"
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The configuration file:
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cpu = /mnt/cgroups/cpu;
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cpuacct = /mnt/cgroups/cpu;
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creates the hierarchy controlled by two subsystems, with no groups
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inside. It corresponds to following operations:
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mkdir /mnt/cgroups/cpu
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mount -t cgroup -o cpu,cpuacct cpu /mnt/cgroups/cpu
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The configuration file:
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cpu = /mnt/cgroups/cpu;
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cpuacct = /mnt/cgroups/cpu;
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creates the hierarchy controlled by two subsystems with one group and
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two subgroups inside, setting one parameter.
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It corresponds to following operations:
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mkdir /mnt/cgroups/cpu
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mount -t cgroup -o cpu,cpuacct cpu /mnt/cgroups/cpu
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mkdir /mnt/cgroups/cpu/daemons
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mkdir /mnt/cgroups/cpu/daemons/www
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chown root:root /mnt/cgroups/cpu/daemons/www/*
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chown root:webmaster /mnt/cgroups/cpu/daemons/www/tasks
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echo 1000 > /mnt/cgroups/cpu/daemons/www/cpu.shares
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mkdir /mnt/cgroups/cpu/daemons/ftp
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chown root:root /mnt/cgroups/cpu/daemons/ftp/*
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chown root:ftpmaster /mnt/cgroups/cpu/daemons/ftp/tasks
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echo 500 > /mnt/cgroups/cpu/daemons/ftp/cpu.shares
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group is created automatically when its first subgroup is
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created. All its parameters have the default value and only root can
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access group's files.
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subsystems are mounted to the same directory, all
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groups are implicitly controlled also by
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subsystem, even if there is no
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section in any of the groups.
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The configuration file:
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cpu = /mnt/cgroups/cpu;
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cpuacct = /mnt/cgroups/cpuacct;
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creates two hierarchies and one common group in both of them.
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It corresponds to following operations:
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mkdir /mnt/cgroups/cpu
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mkdir /mnt/cgroups/cpuacct
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mount -t cgroup -o cpu cpu /mnt/cgroups/cpu
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mount -t cgroup -o cpuacct cpuacct /mnt/cgroups/cpuacct
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mkdir /mnt/cgroups/cpu/daemons
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mkdir /mnt/cgroups/cpuacct/daemons
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In fact there are two groups created. One in
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hierarchy, the second in
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hierarchy. These two groups have nothing in common and can
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contain different subgroups and different tasks.
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The configuration file:
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cpu = /mnt/cgroups/cpu;
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cpuacct = /mnt/cgroups/cpuacct;
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creates two hierarchies with few groups inside. One of groups
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is created in both hierarchies.
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It corresponds to following operations:
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mkdir /mnt/cgroups/cpu
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mkdir /mnt/cgroups/cpuacct
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mount -t cgroup -o cpu cpu /mnt/cgroups/cpu
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mount -t cgroup -o cpuacct cpuacct /mnt/cgroups/cpuacct
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mkdir /mnt/cgroups/cpuacct/daemons
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mkdir /mnt/cgroups/cpu/daemons
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mkdir /mnt/cgroups/cpu/daemons/www
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mkdir /mnt/cgroups/cpu/daemons/ftp
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is created in both hierarchies. In
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hierarchy the group is explicitly mentioned in the configuration
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hierarchy is the group created implicitly when
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is created there. These two groups have nothing in common, for example
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they do not share processes and subgroups. Groups
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hierarchy and are not controlled by
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The configuration file:
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cpu = /mnt/cgroups/cpu;
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cpuacct = /mnt/cgroups/cpu;
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creates the hierarchy controlled by two subsystems with one group with some
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It corresponds to following operations:
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mkdir /mnt/cgroups/cpu
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mount -t cgroup -o cpu,cpuacct cpu /mnt/cgroups/cpu
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chown root:operator /mnt/cgroups/cpu/*
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chown root:operator /mnt/cgroups/cpu/tasks
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mkdir /mnt/cgroups/cpu/daemons
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chown root:operator /mnt/cgroups/cpu/daemons/*
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chown root:daemonmaster /mnt/cgroups/cpu/daemons/tasks
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Users, which are members of the
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group are allowed to administer the control groups, i.e. create new control
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groups and can move processes between these groups without having root
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group can move processes to
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control group, but they can not move the process out of the group. Only
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.SS Keep hierarchies separated
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Having multiple hierarchies is perfectly valid and can be useful
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in various scenarios. To keeps things clean, do not
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create one group in multiple hierarchies. Examples 3 and 4 shows,
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how unreadable and confusing it can be, especially when reading
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somebody others configuration file.
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.SS Explicit is better than implicit
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can implicitly create groups which are needed for creation of
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configured subgroups. This may be useful and save some typing in
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simple scenarios. When it comes to multiple hierarchies, it's
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better to explicitly specify all groups and all controllers
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.B /etc/cgconfig.conf
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default libcgroup configuration file
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Parameter values can be only single string without spaces.
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Parsing of quoted strings is not implemented.
added
removed
doc/man/cgconfig.conf.5
