Installation

System Prerequisites

MUNGE is used to sign job requests submitted to Flux, so the MUNGE daemon should be installed on all nodes running Flux with the same MUNGE key used across the cluster.

System clocks must be synchronized across the cluster, e.g. with Network Time Protocol.

Flux assumes a shared UID namespace across the cluster.

A system user named flux is required. This user need not have a valid home directory or shell.

Flux uses hwloc to verify that configured resources are present on nodes. Ensure that the system installed version includes any plugins needed for the hardware, especially GPUs.

A Word about Core Dumps

It is helpful to enable core dumps from the system instance flux-broker (especially rank 0) so that useful bug reports can be filed should the broker crash. Usually systemd-coredump(8) handles this, which makes core files and stack traces accessible with coredumpctl(1).

Some sites choose instead to configure the kernel.core_pattern sysctl(8) parameter to a relative file path, which directs core files to the program's current working directory. Please note that the system instance broker runs as the flux user with a working directory of / and thus would not have write permission on its current working directory. This can be worked around by installing a systemd override file, e.g.

# /etc/systemd/system/flux.service.d/override.conf
[Service]
WorkingDirectory=/var/lib/flux
LimitCORE=infinity:infinity

Note

If you do observe a flux-broker crash, please open a github issue at https://github.com/flux-framework/flux-core/issues and include the Flux version, relevant log messages from journalctl -u flux, and a stack trace, if available.

Installing Software Packages

The following Flux framework packages are needed for a Flux system instance and should be installed from your Linux distribution package manager.

flux-security

APIs for job signing, and the IMP, a privileged program for starting processes as multiple users. Install on all nodes (required). If building flux-security from source, be sure to configure with --enable-pam to include Pluggable Authentication Modules (PAM) support.

flux-core

All of the core components of Flux, including the Flux broker. flux-core is functional on its own, but cannot run jobs as multiple users, has a simple FIFO scheduler, and does not implement accounting-based job prioritization. If building flux-core from source, be sure to configure with --with-flux-security. Install on all nodes (required).

flux-sched

The Fluxion graph-based scheduler.

flux-accounting (optional)

Management of limits for individual users/projects, banks, and prioritization based on fair-share accounting. For more information on how to configure run flux-accounting, please refer to the Flux Accounting Guide.

flux-pam (optional)

A PAM module that can enable users to login to compute nodes that are running their jobs.

Note

Sites are strongly encouraged to use packages when deploying a system installation of Flux. Source RPM packages are maintained for the TOSS Red Hat Enterprise Linux based Linux distribution and are included with github release assets for each new release. Open an issue in flux-core if you would like to become a maintainer of Flux packages for another Linux distribution so we can share packaging tips and avoid duplicating effort.