CGCONFIG.CONF(5)						File Formats Manual						  CGCONFIG.CONF(5)

NAME

       cgconfig.conf - libcgroup configuration file

DESCRIPTION

       cgconfig.conf  is  a configuration file used by libcgroup to define control groups, their parameters and their mount points.  The file con-
       sists of mount , group and default sections. These sections can be in arbitrary order and all of them are optional. Any line starting  with
       '#' is considered a comment line and is ignored.

       mount section has this form:

	      mount {
		     <controller> = <path>;
		     ...
	      }

       controller
	      Name of the kernel subsystem. The list of subsystems supported by the kernel can be found in /proc/cgroups file. Named hierarchy can
	      be specified as controller "name=<somename>". Do not forget to use double quotes around this controller name (see examples below).

	      Libcgroup merges all subsystems mounted to the same directory (see Example 1) and the directory is mounted only once.

       path   The directory path where the group hierarchy associated to a given controller shall be mounted. The directory is	created  automati-
	      cally on cgconfig service startup if it does not exist and is deleted on service shutdown.

       If no mount section is specified, no controllers are mounted.

       group section has this form:

	      group <name> {
		     [permissions]
		     <controller> {
			    <param name> = <param value>;
			    ...
		     }
		     ...
	      }

       name   Name  of	the  control group. It can contain only characters, which are allowed for directory names.  The groups form a tree, i.e. a
	      control group can contain zero or more subgroups. Subgroups can be specified using '/' delimiter.

	      The root control group is always created automatically in all hierarchies and it is the base of  the  group  hierarchy.  It  can	be
	      explicitly  specified in cgconfig.conf by using '.' as group name. This can be used e.g. to set its permissions, as shown in Example
	      6.

	      When the parent control group of a subgroup is not specified it is created automatically.

       permissions
	      Permissions of the given control group on mounted filesystem.  root has always permission to do anything	with  the  control  group.
	      Permissions have the following syntax:
			perm {
			       task {
				      uid = <task user>;
				      gid = <task group>;
				      fperm = <file permissions>
			       }
			       admin {
				      uid = <admin name>;
				      gid = <admin group>;
				      dperm = <directory permissions>
				      fperm = <file permissions>
			       }
			}

	      task user/group  Name  of  the  user and the group, which own the tasks file of the control group. Given fperm then specify the file
			       permissions.  Please note that the given value is not used as was specified. Instead, current  file  owner  permis-
			       sions  are used as a "umask" for group and others permisions. For example if fperm = 777 then both group and others
			       will get the same permissions as the file owner.

	      admin user/group Name of the user and the group which own the rest of control group's files. Given fperm and dperm control file  and
			       directory permissions.  Again, the given value is masked by the file/directory owner permissions.

	      Permissions  are	only  apply  to the enclosing control group and are not inherited by subgroups. If there is no perm section in the
	      control group definition, root:root is the owner of all files and default file permissions are preserved if fperm  resp.	dperm  are
	      not specified.

       controller
	      Name  of	the  kernel  subsystem.  The section can be empty, default kernel parameters will be used in this case. By specifying con-
	      troller the control group and all its parents are controlled by the specific subsystem. One control group can be controlled by  mul-
	      tiple subsystems, even if the subsystems are mounted on different directories. Each control group must be controlled by at least one
	      subsystem, so that libcgroup knows in which hierarchies the control group should be created.

	      The parameters of the given controller can be modified in the following section enclosed in brackets.

	      param name
		     Name of the file to set. Each controller can have zero or more parameters.

	      param value
		     Value which should be written to the file when the control group is created. If it is enclosed in double quotes `"',  it  can
		     contain spaces and other special characters.

       If no group section is specified, no groups are created.

       default section has this form:

	      default {
		     perm {
			    task {
				   uid = <task user>;
				   gid = <task group>;
				   fperm = <file permissions>
			    }
			    admin {
				   uid = <admin name>;
				   gid = <admin group>;
				   dperm = <directory permissions>
				   fperm = <file permissions>
			    }
		     }
	      }

       Content of the perm section has the same form as in group section. The permissions defined here specify owner and permissions of groups and
       files of all groups, which do not have explicitly specified their permissions in their group section.

EXAMPLES

   Example 1
       The configuration file:

	      mount {
		     cpu = /mnt/cgroups/cpu;
		     cpuacct = /mnt/cgroups/cpu;
	      }

       creates the hierarchy controlled by two subsystems with no groups inside. It corresponds to the following operations:

	      mkdir /mnt/cgroups/cpu
	      mount -t cgroup -o cpu,cpuacct cpu /mnt/cgroups/cpu

   Example 2
       The configuration file:

	      mount {
		     cpu = /mnt/cgroups/cpu;
		     "name=scheduler" = /mnt/cgroups/cpu;
		     "name=noctrl" = /mnt/cgroups/noctrl;
	      }

	      group daemons {
		     cpu {
			    cpu.shares = "1000";
		     }
	      }
	      group test {
		     "name=noctrl" {
		     }
	      }
       creates two hierarchies. One hierarchy named scheduler controlled by cpu subsystem, with group daemons inside. Second  hierarchy  is  named
       noctrl without any controller, with group test. It corresponds to following operations:

	      mkdir /mnt/cgroups/cpu
	      mount -t cgroup -o cpu,name=scheduler cpu /mnt/cgroups/cpu
	      mount -t cgroup -o none,name=noctrl none /mnt/cgroups/noctrl

	      mkdir /mnt/cgroups/cpu/daemons
	      echo 1000 > /mnt/cgroups/cpu/daemons/www/cpu.shares

	      mkdir /mnt/cgroups/noctrl/tests

       The  daemons group is created automatically when its first subgroup is created. All its parameters have the default value and only root can
       access group's files.

       Since both cpuacct and cpu subsystems are mounted to the same directory, all groups are implicitly controlled also  by  cpuacct	subsystem,
       even if there is no cpuacct section in any of the groups.

   Example 3
       The configuration file:

	      mount {
		     cpu = /mnt/cgroups/cpu;
		     cpuacct = /mnt/cgroups/cpu;
	      }

	      group daemons/www {
		     perm {
			    task {
				   uid = root;
				   gid = webmaster;
				   fperm = 770;
			    }
			    admin {
				   uid = root;
				   gid = root;
				   dperm = 775;
				   fperm = 744;
			    }
		     }
		     cpu {
			    cpu.shares = "1000";
		     }
	      }

	      group daemons/ftp {
		     perm {
			    task {
				   uid = root;
				   gid = ftpmaster;
				   fperm = 774;
			    }
			    admin {
				   uid = root;
				   gid = root;
				   dperm = 755;
				   fperm = 700;
			    }
		     }
		     cpu {
			    cpu.shares = "500";
		     }
	      }
       creates	the  hierarchy controlled by two subsystems with one group and two subgroups inside, setting one parameter.  It corresponds to the
       following operations (except for file permissions which are little bit trickier to emulate via chmod):

	      mkdir /mnt/cgroups/cpu
	      mount -t cgroup -o cpu,cpuacct cpu /mnt/cgroups/cpu

	      mkdir /mnt/cgroups/cpu/daemons

	      mkdir /mnt/cgroups/cpu/daemons/www
	      chown root:root /mnt/cgroups/cpu/daemons/www/*
	      chown root:webmaster /mnt/cgroups/cpu/daemons/www/tasks
	      echo 1000 > /mnt/cgroups/cpu/daemons/www/cpu.shares

	       # + chmod the files so the result looks like:
	       # ls -la /mnt/cgroups/cpu/daemons/www/
	       # admin.dperm = 755:
	       # drwxr-xr-x. 2 root webmaster 0 Jun 16 11:51 .
	       #
	       # admin.fperm = 744:
	       # --w-------. 1 root webmaster 0 Jun 16 11:51 cgroup.event_control
	       # -r--r--r--. 1 root webmaster 0 Jun 16 11:51 cgroup.procs
	       # -r--r--r--. 1 root webmaster 0 Jun 16 11:51 cpuacct.stat
	       # -rw-r--r--. 1 root webmaster 0 Jun 16 11:51 cpuacct.usage
	       # -r--r--r--. 1 root webmaster 0 Jun 16 11:51 cpuacct.usage_percpu
	       # -rw-r--r--. 1 root webmaster 0 Jun 16 11:51 cpu.rt_period_us
	       # -rw-r--r--. 1 root webmaster 0 Jun 16 11:51 cpu.rt_runtime_us
	       # -rw-r--r--. 1 root webmaster 0 Jun 16 11:51 cpu.shares
	       # -rw-r--r--. 1 root webmaster 0 Jun 16 11:51 notify_on_release
	       #
	       # tasks.fperm = 770
	       # -rw-rw----. 1 root webmaster 0 Jun 16 11:51 tasks

	      mkdir /mnt/cgroups/cpu/daemons/ftp
	      chown root:root /mnt/cgroups/cpu/daemons/ftp/*
	      chown root:ftpmaster /mnt/cgroups/cpu/daemons/ftp/tasks
	      echo 500 > /mnt/cgroups/cpu/daemons/ftp/cpu.shares

	       # + chmod the files so the result looks like:
	       # ls -la /mnt/cgroups/cpu/daemons/ftp/
	       # admin.dperm = 755:
	       # drwxr-xr-x. 2 root ftpmaster 0 Jun 16 11:51 .
	       #
	       # admin.fperm = 700:
	       # --w-------. 1 root ftpmaster 0 Jun 16 11:51 cgroup.event_control
	       # -r--------. 1 root ftpmaster 0 Jun 16 11:51 cgroup.procs
	       # -r--------. 1 root ftpmaster 0 Jun 16 11:51 cpuacct.stat
	       # -rw-------. 1 root ftpmaster 0 Jun 16 11:51 cpuacct.usage
	       # -r--------. 1 root ftpmaster 0 Jun 16 11:51 cpuacct.usage_percpu
	       # -rw-------. 1 root ftpmaster 0 Jun 16 11:51 cpu.rt_period_us
	       # -rw-------. 1 root ftpmaster 0 Jun 16 11:51 cpu.rt_runtime_us
	       # -rw-------. 1 root ftpmaster 0 Jun 16 11:51 cpu.shares
	       # -rw-------. 1 root ftpmaster 0 Jun 16 11:51 notify_on_release
	       #
	       # tasks.fperm = 774:
	       # -rw-rw-r--. 1 root ftpmaster 0 Jun 16 11:51 tasks

       The daemons group is created automatically when its first subgroup is created. All its parameters have the default value and only root  can
       access the group's files.

       Since  both  cpuacct and cpu subsystems are mounted to the same directory, all groups are implicitly also controlled by the cpuacct subsys-
       tem, even if there is no cpuacct section in any of the groups.

   Example 4
       The configuration file:

	      mount {
		     cpu = /mnt/cgroups/cpu;
		     cpuacct = /mnt/cgroups/cpuacct;
	      }

	      group daemons {
		     cpuacct{
		     }
		     cpu {
		     }
	      }
       creates two hierarchies and one common group in both of them.  It corresponds to the following operations:

	      mkdir /mnt/cgroups/cpu
	      mkdir /mnt/cgroups/cpuacct
	      mount -t cgroup -o cpu cpu /mnt/cgroups/cpu
	      mount -t cgroup -o cpuacct cpuacct /mnt/cgroups/cpuacct

	      mkdir /mnt/cgroups/cpu/daemons
	      mkdir /mnt/cgroups/cpuacct/daemons

       In fact there are two groups created. One in the cpuacct hierarchy, the second in the cpu hierarchy. These two groups have nothing in  com-
       mon and can contain different subgroups and different tasks.

   Example 5
       The configuration file:

	      mount {
		     cpu = /mnt/cgroups/cpu;
		     cpuacct = /mnt/cgroups/cpuacct;
	      }

	      group daemons {
		     cpuacct{
		     }
	      }

	      group daemons/www {
		     cpu {
			    cpu.shares = "1000";
		     }
	      }

	      group daemons/ftp {
		     cpu {
			    cpu.shares = "500";
		     }
	      }
       creates two hierarchies with few groups inside. One of the groups is created in both hierarchies.

       It corresponds to the following operations:

	      mkdir /mnt/cgroups/cpu
	      mkdir /mnt/cgroups/cpuacct
	      mount -t cgroup -o cpu cpu /mnt/cgroups/cpu
	      mount -t cgroup -o cpuacct cpuacct /mnt/cgroups/cpuacct

	      mkdir /mnt/cgroups/cpuacct/daemons
	      mkdir /mnt/cgroups/cpu/daemons
	      mkdir /mnt/cgroups/cpu/daemons/www
	      echo 1000 > /mnt/cgroups/cpu/daemons/www/cpu.shares
	      mkdir /mnt/cgroups/cpu/daemons/ftp
	      echo 500 > /mnt/cgroups/cpu/daemons/ftp/cpu.shares
       Group  daemons is created in both hierarchies. In the cpuacct hierarchy the group is explicitly mentioned in the configuration file. In the
       cpu hierarchy the group is created implicitly when www is created there. These two groups have nothing in common, for example they  do  not
       share processes and subgroups. Groups www and ftp are created only in the cpu hierarchy and are not controlled by the cpuacct subsystem.

   Example 6
       The configuration file:

	      mount {
		     cpu = /mnt/cgroups/cpu;
		     cpuacct = /mnt/cgroups/cpu;
	      }

	      group . {
		     perm {
			    task {
				   uid = root;
				   gid = operator;
			    }
			    admin {
				   uid = root;
				   gid = operator;
			    }
		     }
		     cpu {
		     }
	      }

	      group daemons {
		     perm {
			    task {
				   uid = root;
				   gid = daemonmaster;
			    }
			    admin {
				   uid = root;
				   gid = operator;
			    }
		     }
		     cpu {
		     }
	      }
       creates	the hierarchy controlled by two subsystems with one group having some special permissions.  It corresponds to the following opera-
       tions:

	      mkdir /mnt/cgroups/cpu
	      mount -t cgroup -o cpu,cpuacct cpu /mnt/cgroups/cpu

	      chown root:operator /mnt/cgroups/cpu/*
	      chown root:operator /mnt/cgroups/cpu/tasks

	      mkdir /mnt/cgroups/cpu/daemons
	      chown root:operator /mnt/cgroups/cpu/daemons/*
	      chown root:daemonmaster /mnt/cgroups/cpu/daemons/tasks

       Users which are members of the operator group are allowed to administer the control groups, i.e. create new control groups  and	move  pro-
       cesses between these groups without having root privileges.

       Members of the daemonmaster group can move processes to the daemons control group, but they can not move the process out of the group. Only
       the operator or root can do that.

RECOMMENDATIONS

   Keep hierarchies separated
       Having multiple hierarchies is perfectly valid and can be useful in various scenarios. To keeps things clean, do not create  one  group	in
       multiple  hierarchies.  Examples  4 and 5 show how unreadable and confusing it can be, especially when reading somebody elses configuration
       file.

   Explicit is better than implicit
       libcgroup can implicitly create groups which are needed for the creation of configured subgroups. This may be useful and save  some  typing
       in  simple  scenarios.  When  it comes to multiple hierarchies, it's better to explicitly specify all groups and all controllers related to
       them.

FILES

       /etc/cgconfig.conf
       default libcgroup configuration file

SEE ALSO

       cgconfigparser (8)

BUGS

       Parameter values must be single strings without spaces.	Parsing of quoted strings is not implemented.

																  CGCONFIG.CONF(5)