Ubuntu Manpage: cgroup.conf - Slurm configuration file for the cgroup support

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
       #

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