The flux-security project concentrates the security sensitive portions of Flux. To maintain isolation, it implements two independent TOML configuration hierarchies, separate from the rest of Flux. Their paths are set when flux-security is built and cannot be altered at runtime:


Configuration file(s) for flux-imp(8), described in flux-config-security-imp(5).


Configuration file(s) for the signing library, described in flux-config-security-sign(5).

As with flux-config(5), Flux security configuration files follow the TOML file format, with configuration subdivided by function into separate TOML tables. The tables for each hierarchy may all appear in a single .toml file or be fragmented in multiple files that match the appropriate glob(7) pattern. The configuration is assumed to be identical for all Flux components across a given Flux instance.

Security configuration files, including the conf.d directory and individual .toml files, must be appropriately locked down:

  • owner of root

  • group of root

  • must not be writable by others

  • must not be a symbolic link

  • .toml files must be regular files

There is no mechanism to tell Flux components to reread the Flux security configurations when they change. Most Flux security users such as flux-mini(1) or flux-imp(8) are short lived and read the latest configuration on each invocation. There are two considerations to be aware of when updating the signing configuration, however:

  • The job-ingest service validates the signatures of job requests. As a flux-broker(1) plugin, it runs for the duration of the rank 0 broker and could reject job submissions if a mismatched signing configuration is picked up by the job submission tools.

  • Pending jobs could fail to start if the signing configuration used when they were submitted no longer matches the signing configuration read by the IMP at job startup.

It is therefore recommended that the Flux instance be cleared of pending jobs and fully stopped when updating the signing configuration.


Flux: http://flux-framework.org

Flux Administrator's Guide: https://flux-framework.readthedocs.io/en/latest/adminguide.html

TOML: Tom's Obvious Minimal Language: https://toml.io/en/

RFC 15: Independent Minister of Privilege for Flux: The Security IMP: https://flux-framework.readthedocs.io/projects/flux-rfc/en/latest/spec_15.html


flux-config(5), flux-config-security-imp(5), flux-config-security-sign(5)