slurmd(8)

📦
version 26.05.4 · 6 versions
, in ubuntu stonking

🎀 slurmd(8) — Slurm Daemon 🎀

okay so bestie, gather round, because this is part 1 of 2 of the slurmd(8) manual page and it is a lot. slay. let's get into it 💖

✨ NAME ✨

slurmd — the compute node daemon for Slurm. that's the whole vibe. it's the one holding it down on the compute node. 👑

✨ SYNOPSIS ✨

slurmd [OPTIONS...]

literally just that. options in, daemon out. 🌸

✨ DESCRIPTION ✨

slurmd is the compute node daemon of Slurm, no cap. it does the following, and it does it fiercely:

  • monitors all tasks running on the compute node
  • accepts work (tasks) 📥
  • launches tasks 🚀
  • kills running tasks upon request 💀

that's the job. it's giving main character energy on every node. 🦋

✨ OPTIONS ✨

okay this is the long part. every single one. no skipping, we're not that girl. 🫶

  • --authinfo — used with configless to set an alternate AuthInfo parameter to be used to establish communication with slurmctld before the configuration file has been retrieved. (E.g., to specify an alternate MUNGE socket location.) iykyk. 🔑
  • -b — report node rebooted when daemon restarted. used for testing purposes. that's it, that's the flag. 🧪
  • -c — clear system locks as needed. this may be required if slurmd terminated abnormally. messy queen behavior, we fix it. 🧹
  • -C — print the actual hardware configuration (not the configuration from the slurm.conf file) and exit. the format of output is the same as used in slurm.conf to describe a node's configuration plus its uptime. you may use --parameters to specify options such as 'l3cache_as_socket' which may alter the reported node topology. 💻
  • --ca-cert-file <file> — absolute path to CA certificate used for fetching configuration when running configless in a TLS enabled cluster. 🔐
  • --conf <node parameters> — used in conjunction with the -Z option. used to override or define additional parameters of a dynamic node using the same syntax and parameters used to define nodes in the slurm.conf. specifying any of CPUs, Boards, SocketsPerBoard, CoresPerSocket or ThreadsPerCore will override the defaults defined by the -C option. NodeName and Port are not supported. this can also be used to specify a cloud node's topology, in which case the -Z flag should not be used (e.g., --conf="topology=topo-switch:s1").

for example if slurmd -C reports

NodeName=node1 CPUs=16 Boards=1 SocketsPerBoard=1 CoresPerSocket=8 ThreadsPerCore=2 RealMemory=31848

the following --conf specifications will generate the corresponding node definitions:

--conf "Gres=gpu:2"
NodeName=node1 CPUs=16 Boards=1 SocketsPerBoard=1 CoresPerSocket=8 ThreadsPerCore=2 RealMemory=31848 Gres=gpu:2
--conf "RealMemory=30000"
NodeName=node1 CPUs=16 Boards=1 SocketsPerBoard=1 CoresPerSocket=8 ThreadsPerCore=2 RealMemory=30000
--conf "CPUs=16"
NodeName=node1 CPUs=16 RealMemory=331848
--conf "CPUs=16 RealMemory=30000 Gres=gpu:2"
NodeName=node1 CPUs=16 RealMemory=30000 Gres=gpu:2"

GPU detection occurs automatically when:

  • --conf does not specify any GPU GRES
  • gres.conf does not contain any explicit GPU GRES records for the node
  • gres.conf does not contain AutoDetect=off

if AutoDetect in gres.conf specifies a particular detection mechanism (e.g., NVML, NVIDIA, RSMI, oneAPI, NRT), it will use that mechanism to try to detect a GPU. if no AutoDetect is specified, the slurmd defaults to the full GPU detection method.

the following shows GPU autodetection behavior for a node with 2 local A100 GPUs:

no --conf, no AutoDetect in gres.conf:
NodeName=node1 CPUs=16 Boards=1 SocketsPerBoard=1 CoresPerSocket=8 ThreadsPerCore=2 RealMemory=31848 Gres=gpu:a100:2
--conf "Gres=tmpfs:1000", no AutoDetect in gres.conf:
NodeName=node1 CPUs=16 Boards=1 SocketsPerBoard=1 CoresPerSocket=8 ThreadsPerCore=2 RealMemory=31848 Gres=tmpfs:1000,gpu:a100:2
--conf "Gres=tmpfs:1000", AutoDetect=nvml in gres.conf:
NodeName=node1 CPUs=16 Boards=1 SocketsPerBoard=1 CoresPerSocket=8 ThreadsPerCore=2 RealMemory=31848 Gres=tmpfs:1000,gpu:a100:2
--conf "Gres=tmpfs:1000", AutoDetect=off in gres.conf:
NodeName=node1 CPUs=16 Boards=1 SocketsPerBoard=1 CoresPerSocket=8 ThreadsPerCore=2 RealMemory=31848 Gres=tmpfs:1000
  • --conf-server <host|ip address>[:<port>] — comma-separated list of controllers, the first being the primary slurmctld. a port can (optionally) be specified for each controller. these hosts are where the slurmd will fetch the configuration from when running in "configless" mode. NOTE: if specifying an IPv6 address, wrap the <ip address> in [] to distinguish the address from the port. this is required even if no port is specified. bestie the brackets are not optional okay 😭
  • -d <file> — specify the fully qualified pathname to the slurmstepd program to be used for shepherding user job steps. this can be useful for testing purposes. 🧪
  • -D — run slurmd in the foreground with logging copied to stderr. front and center, no hiding. 💅
  • --extra <arbitrary string> — set "extra" data on node startup. if this is a json string and SchedulerParameters=extra_constraints is set in slurm.conf, then jobs may use the --extra option to filter based on this "extra" data. ✨
  • -f <file> — read configuration from the specified file. see NOTES below. 📄
  • -F[feature] — start this node as a Dynamic Future node. it will try to match a node definition with a state of FUTURE, optionally using the specified feature to match the node definition. manifesting your future node fr fr 🌈
  • -G — print Generic RESource (GRES) configuration (based upon slurm.conf GRES merged with gres.conf contents for this node) and exit. 🎁
  • -h — help; print a brief summary of command options. we love a queen who asks for directions 🫶
  • --instance-id <cloud instance id> — set cloud instance ID on node startup. ☁️
  • --instance-type <cloud instance type> — set cloud instance type on node startup. ☁️✨
  • -L <file> — write log messages to the specified file. 📝
  • -M — lock slurmd pages into system memory using mlockall (2) to disable paging of the slurmd process. this may help in cases where nodes are marked DOWN during periods of heavy swap activity. if the mlockall (2) system call is not available, an error will be printed to the log and slurmd will continue as normal. it is suggested to set LaunchParameters=slurmstepd_memlock in slurm.conf(5) when setting -M. 🔒
  • -n <value> — set the daemon's nice value to the specified value, typically a negative number. also note the PropagatePrioProcess configuration parameter. 😌
  • -N <nodename> — run the daemon with the given nodename. used to emulate a larger system with more than one slurmd daemon per node. requires that Slurm be built using the --enable-multiple-slurmd configure option. 💫
  • --parameters <slurmd parameters> — allows for temporary node-specific changes to SlurmdParameters. can be used alongside -C to specify options such as 'l3cache_as_socket' which may alter the reported node topology. these parameters are appended to any node-specific Parameters defined in slurm.conf. 🎛️
  • -s — change working directory of slurmd to SlurmdLogFile path if possible, or to SlurmdSpoolDir otherwise. if both of them fail it will fallback to /var/tmp. plan A, plan B, plan C, we stay housed 🏠
  • --systemd — use when starting the daemon with systemd. this will allow slurmd to notify systemd of the new PID when using 'scontrol reconfigure'. 🌀
  • -v — verbose operation. multiple -v's increase verbosity. louder = better, as always 📢
  • -V, --version — print version information and exit. 💌
  • -Z — start this node as a Dynamic Normal node. if no --conf is specified, then the slurmd will register with the same hardware configuration (except GRES) as defined by the -C option. 🦋

✨ ENVIRONMENT VARIABLES ✨

the following environment variables can be used to override settings compiled into slurmd. yes bestie, you can override the factory settings. 🌈

  • ABORT_ON_FATAL — when a fatal error is detected, use abort() instead of exit() to terminate the process. this allows backtraces to be captured without recompiling Slurm. 💀 (affectionate)
  • SLURM_CONF — the location of the Slurm configuration file. this is overridden by explicitly naming a configuration file on the command line. 📁
  • SLURM_DEBUG_FLAGS — specify debug flags for slurmd to use. see DebugFlags in the slurm.conf(5) man page for a full list of flags. the environment variable takes precedence over the setting in the slurm.conf. 🏆

✨ HTTP server ✨

unless disabled via CommunicationParameters=disable_http in slurm.conf, slurmd will accept incoming HTTP/1.1 compliant requests to any socket listening as configured by SlurmdPort in slurm.conf. authentication of HTTP requests is not supported. TLS wrapping optionally supported without requiring TLSType in slurm.conf. the following endpoints are currently supported:

  • GET / — get list of endpoints. 📜
  • GET /healthz — test if slurmd loaded successfully. 🩺
  • GET /livez — test if slurmd loaded successfully. 🌡️
  • GET /readyz[?verbose] — test if slurmd is ready to accept incoming RPCs. adding the verbose query parameter will result in a verbose output of each probe in the response. 🗣️

✨ SIGNALS ✨

  • SIGTERM SIGINT SIGQUIT — slurmd will shutdown cleanly. graceful exit, we love to see it 💅
  • SIGHUP — reloads the slurm configuration files, similar to 'scontrol reconfigure'. 🔄
  • SIGUSR2 — reread the log level from the configs, and then reopen the log file. this should be used when setting up logrotate(8). 🪵
  • SIGPIPE — this signal is explicitly ignored. not today, not ever 🙈

✨ CORE FILE LOCATION ✨

if slurmd is started with the -D option then the core file will be written to the current working directory. otherwise if SlurmdLogFile is a fully qualified path name (starting with a slash), the core file will be written to the same directory as the log file. otherwise the core file will be written to the SlurmdSpoolDir directory, or "/var/tmp/" as a last resort. if none of the above directories can be written, no core file will be produced. 😭

✨ NOTES ✨

it may be useful to experiment with different slurmd specific configuration parameters using a distinct configuration file (e.g. timeouts). however, this special configuration file will not be used by the slurmctld daemon or the Slurm programs, unless you specifically tell each of them to use it. if you desire changing communication ports, the location of the temporary file system, or other parameters used by other Slurm components, change the common configuration file, slurm.conf. 🛠️

if you are using configless mode with a login node that runs a lot of client commands, you may consider running slurmd on that machine so it can manage a cached version of the configuration files. otherwise, each client command will use the DNS record to contact the controller and get the configuration information, which could place additional load on the controller. 🧠✨

💖 COPYING ✨

Okay bestie, legal bit time, and I need you to actually read it because it's the receipts of who made this:

  • Copyright (C) 2002-2007 The Regents of the University of California.
  • Copyright (C) 2008-2010 Lawrence Livermore National Security. Copyright (C) 2010-2022 SchedMD LLC. Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).

This file is part of Slurm, a resource management program. For details, see <https://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.

ngl the ALL CAPS WARRANTY SENTENCE is doing a lot of yelling and it is 100% on purpose. No warranty, bestie. None. Read the GPL for the rest.

🗂️ FILES

  • /etc/slurm.conf

Like, that's it. That's the file. The whole configuration serve is right there and it is main character energy 🎀

👀 SEE ALSO

So slurm.conf(5) is where all the settings live, and slurmctld(8) is the controller — the boss that this daemon talks to. Go read both, iykyk 🌸

And that's the whole page, bestie, we did it 🫶 This one shipped with Slurm 26.05, it's titled Slurm Daemon, and its page name is slurmd(8). Go be a good little compute node now 💅✨

📦 where this page comes from