Flux Integration

Flux integration is now based on job metadata carrying a signed probes file and the datacrumbs@<job-id>.service systemd unit.

Current Flow

  1. User generates a signed probes file.

  2. User submits with:

    flux run --datacrumbs-enable --datacrumbs-probe-file /path/to/probes.json.gz ...

  3. The Flux plugin writes job metadata containing:

    {"datacrumbs":{"enable":"yes","probe_file":"/path/to/probes.json.gz"}}

  4. Flux prolog runs datacrumbs_service_run.sh.

  5. The script resolves the job id, user, and probe file, writes datacrumbs-<jobid>.env, and starts datacrumbs@<jobid>.service.

  6. The systemd unit waits until the ready file exists.

  7. Flux epilog runs datacrumbs_service_stop.sh, which stops the service and waits for it to exit.

Installed components

  • login node: - <install-prefix>/etc/datacrumbs/systemd/datacrumbs_sign_probes.service

  • <install-prefix>/etc/datacrumbs/systemd/datacrumbs@.service

  • <install-prefix>/sbin/datacrumbs_service_run.sh

  • <install-prefix>/sbin/datacrumbs_service_stop.sh

  • <install-prefix>/etc/datacrumbs/flux/cli/plugins/datacrumbs.py

Login-node prerequisite

Before users generate probe files for Flux jobs, the trusted signing service must be running on the login node:

sudo ln -sf <install-prefix>/etc/datacrumbs/systemd/datacrumbs_sign_probes.service \
  /etc/systemd/system/datacrumbs_sign_probes.service
sudo systemctl daemon-reload
sudo systemctl enable --now datacrumbs_sign_probes.service

Deploying the unit

sudo ln -sf <install-prefix>/etc/datacrumbs/systemd/datacrumbs@.service \
  /etc/systemd/system/datacrumbs@.service
sudo systemctl daemon-reload

Plugin behavior

The Flux plugin now uses probe_file, not composite, as the runtime selector.

Expected CLI options:

  • –datacrumbs-enable

  • –datacrumbs-probe-file PATH

Testing without a real Flux prolog

Use the installed service wrapper:

datacrumbs_service_wrapper start 1 <user> /path/to/probes.json.gz
datacrumbs_service_wrapper stop 1 <user> /path/to/probes.json.gz

This fabricates the expected Flux metadata so the service-common path can be tested without modifying the real prolog scripts.