Slurm

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Slurm (also referred as Slurm Workload Manager or slurm-llnl) is an open-source workload manager designed for Linux clusters of all sizes, used by many of the world's supercomputers and computer clusters. It provides three key functions. First it allocates exclusive and/or non-exclusive access to resources (computer nodes) to users for some duration of time so they can perform work. Second, it provides a framework for starting, executing, and monitoring work (typically a parallel job) on a set of allocated nodes. Finally, it arbitrates contention for resources by managing a queue of pending work.

Installation

Install the slurm-llnlAUR package found in the AUR. It pulls in mungeAUR, an authentication service, as a dependency. It is started as a requirement through slurmd's systemd service and encrypts the connection between the various hosts. Therefore make sure that all nodes in your cluster have the same key in /etc/munge/munge.key.

The package itself has many more optional dependencies, though Slurm has to be recompiled to make use of them, after they have been installed.

Setup

The configuration files for slurm-llnl reside under /etc/slurm-llnl. Prior to starting any slurm-services, it has to be configured properly by creating a configuration file at /etc/slurm-llnl/slurm.conf. Client and server may use the same configuration file, which can either be generated at the official website or by copying /etc/slurm-llnl/slurm.conf.example to /etc/slurm-llnl/slurm.conf and adapting it to ones liking.

By default the Slurm user, which was introduced to your system in the installation process, has 64030 as UID and GID, this simplifies the setup on multiple systems. UID and GID matches the one used in Debian, therefore they may be used side-by-side, but remember that binaries are not in the same directories on each and every distribution.

Client (compute node) configuration

On the client-side one may now safely start/enable slurmd.service.

Note:
  • If you choose to use Linux cgroups for process tracking, the cgroup.conf configuration file must be created on each client. See the cgroup.conf manual page for configuration details.
  • Slurm is not compatible with cgroups v2. If you choose to use cgroups, you must enable cgroups v1 on the Slurm clients. See cgroups#Enable cgroup v1.

Server (head node) configuration

Start/enable slurmctld.service.

Additionally you may want to start/enable slurmdbd.service, which handles a SQL database for easier management thereby logging somewhat essential process information.

Note: Additional arguments may be passed to the program by adapting /etc/default/slurm-llnl though still utilizing the power of systemd. This file is handled as the environment file for the various services and simply passes any arguments on to the program.

Troubleshooting

Services fail to start on boot

If slurmd.service or slurmctld.service fail to start at boot but work fine when manually started, then the service may be trying to start before a network connection has been established. To verify this, add the lines associated with the failing service from below to the slurm.conf file:

SlurmctldDebug=info
SlurmctldLogFile=/var/log/slurm-llnl/slurmctld.log
SlurmdDebug=info
SlurmdLogFile=/var/log/slurm-llnl/slurmd.log

Then, check the associated log file. If you notice the fatal exception mentions Address family not supported by protocol, then you may want to extend the unit so that it waits for a valid network connection via network-online.target.

See also