cgroup.conf (5)

NAME
DESCRIPTION
TASK/CGROUP PLUGIN
DISTRIBUTION-SPECIFIC NOTES
EXAMPLE
COPYING
SEE ALSO

NAME

cgroup.conf - Slurm configuration file for the cgroup support

DESCRIPTION

cgroup.conf is an ASCII file which defines parameters used by Slurm's Linux cgroup related plugins. The file location can be modified at system build time using the DEFAULT_SLURM_CONF parameter or at execution time by setting the SLURM_CONF environment variable. The file will always be located in the same directory as the slurm.conf file.

Parameter names are case insensitive. Any text following a "#" in the configuration file is treated as a comment through the end of that line. Changes to the configuration file take effect upon restart of SLURM daemons, daemon receipt of the SIGHUP signal, or execution of the command "scontrol reconfigure" unless otherwise noted.

For general Slurm Cgroups information, see the Cgroups Guide at <http://slurm.schedmd.com/cgroups.html>.

The following cgroup.conf parameters are defined to control the general behavior of Slurm cgroup plugins.

CgroupMountpoint=PATH: Specify the PATH under which cgroups should be mounted. This should be a writable directory which will contain cgroups mounted one per subsystem. The default PATH is /cgroup.
CgroupAutomount=<yes|no>: Slurm cgroup plugins require valid and functional cgroup subsystem to be mounted under /cgroup/<subsystem_name>. When launched, plugins check their subsystem availability. If not available, the plugin launch fails unless CgroupAutomount is set to yes. In that case, the plugin will first try to mount the required subsystems.
CgroupReleaseAgentDir=<path_to_release_agent_directory>: Used to tune the cgroup system behavior. This parameter identifies the location of the directory containing Slurm cgroup release_agent files.

TASK/CGROUP PLUGIN

The following cgroup.conf parameters are defined to control the behavior of this particular plugin:

ConstrainCores=<yes|no>: If configured to "yes" then constrain allowed cores to the subset of allocated resources. It uses the cpuset subsystem. The default value is "no".
TaskAffinity=<yes|no>: If configured to "yes" then set a default task affinity to bind each step task to a subset of the allocated cores using sched_setaffinity. The default value is "no".
AllowedRAMSpace=<number>: Constrain the job cgroup RAM to this percentage of the allocated memory. The percentage supplied may be expressed as floating point number, e.g. 98.5. If the AllowedRAMSpace limit is exceeded, the job steps will be killed and a warning message will be written to standard error. Also see ConstrainRAMSpace. The default value is 100.
AllowedSwapSpace=<number>: Constrain the job cgroup swap space to this percentage of the allocated memory. The default value is 0, which means that RAM+Swap will be limited to AllowedRAMSpace. The supplied percentage may be expressed as a floating point number, e.g. 50.5. If the limit is exceeded, the job steps will be killed and a warning message will be written to standard error. Also see ConstrainSwapSpace.
ConstrainRAMSpace=<yes|no>: If configured to "yes" then constrain the job's RAM usage. The default value is "no", in which case the job's RAM limit will be set to its swap space limit. Also see AllowedSwapSpace, AllowedRAMSpace and ConstrainSwapSpace.
ConstrainSwapSpace=<yes|no>: If configured to "yes" then constrain the job's swap space usage. The default value is "no". Note that when set to "yes" and ConstrainRAMSpace is set to "no", AllowedRAMSpace is automatically set to 100% in order to limit the RAM+Swap amount to 100% of job's requirement plus the percent of allowed swap space. This amount is thus set to both RAM and RAM+Swap limits. This means that in that particular case, ConstrainRAMSpace is automatically enabled with the same limit than the one used to constrain swap space. Also see AllowedSwapSpace.
MaxRAMPercent=PERCENT: Set an upper bound in percent of total RAM on the RAM constraint for a job. This will be the memory constraint applied to jobs that are not explicitly allocated memory by Slurm (i.e. Slurm's select plugin is not configured to manage memory allocations). The PERCENT may be an arbitrary floating point number. The default value is 100.
MaxSwapPercent=PERCENT: Set an upper bound (in percent of total RAM) on the amount of RAM+Swap that may be used for a job. This will be the swap limit applied to jobs on systems where memory is not being explicitly allocated to job. The PERCENT may be an arbitrary floating point number between 0 and 100. The default value is 100.
MinRAMSpace=<number>: Set a lower bound (in MB) on the memory limits defined by AllowedRAMSpace and AllowedSwapSpace. This prevents accidentally creating a memory cgroup with such a low limit that slurmstepd is immediately killed due to lack of RAM. The default limit is 30M.
ConstrainDevices=<yes|no>: If configured to "yes" then constrain the job's allowed devices based on GRES allocated resources. It uses the devices subsystem for that. The default value is "no".
AllowedDevicesFile=<path_to_allowed_devices_file>: If the ConstrainDevices field is set to "yes" then this file has to be used to declare the devices that need to be allowed by default for all the jobs. The current implementation of cgroup devices subsystem works as a whitelist of entries, which means that in order to isolate the access of a job upon particular devices we need to allow the access on all the devices, supported by default and then deny on those that the job does not have the permission to use. The default value is "/etc/slurm/cgroup_allowed_devices_file.conf". The syntax of the file accepts one device per line and it permits lines like /dev/sda* or /dev/cpu/*/*. See also an example of this file in etc/allowed_devices_file.conf.example.

DISTRIBUTION-SPECIFIC NOTES

Debian and derivatives (e.g. Ubuntu) usually exclude the memory and memsw (swap) cgroups by default. To include them, add the following parameters to the kernel command line: cgroup_enable=memory swapaccount=1

This can usually be placed in /etc/default/grub inside the GRUB_CMDLINE_LINUX variable. A command such as update-grub must be run after updating the file.

EXAMPLE

###
# Slurm cgroup support configuration file
###
CgroupAutomount=yes
CgroupReleaseAgentDir="/etc/slurm/cgroup"
ConstrainCores=yes
#

COPYING

This file is part of SLURM, a resource management program. For details, see <http://slurm.schedmd.com/>.

SLURM is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

SLURM is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.