Task-manager usage¶

For operators: workspaces, submission, managers, and inspecting what they leave behind. The everyday cycle is four commands:

$ httk workflow workspace init . --name default
$ httk workflow job new --workflow vasp-relax --input structure=POSCAR --tag silicon
$ httk workflow run                 # serve jobs until idle (--idle keeps serving)
$ httk workflow workspace status

Managers drive every claimable job through its steps and record everything they do; job list, job show, job log, and job why (why is this job not progressing?) read it back, precheck reports readiness before a manager ever starts, and job debug drives one job in the foreground while you author a runner.

Environment preludes¶

Shell setup an HPC job needs — module load, source activate, export — is carried by two prelude layers, both run under set -e so a failing line aborts the job instead of running the calculation in a half-set-up environment:

Layer 1, environment.prelude — workspace-wide, applies to every job. Set it with workspace settings set NAME environment.prelude "…". For a slurm remote it is written into the generated login-shell submit script, so it runs once inside the allocation and the manager and every runner it spawns inherit it; for a local remote it wraps the manager start; a manager you start yourself with manager run inherits your own shell, so run it from a shell that already has your setup.
Layer 2, workflow-prelude — per workflow, keyed by workflow id, applies only to that workflow’s jobs and runs after Layer 1. Each launch sources it with bash -l (a login shell, so module is available):
```
$ httk workflow workspace workflow-prelude set default relax-vasp "module load VASP/6.2.1"
```

Enabling either layer runs the manager and runners under a login shell, which re-sources login profiles (/etc/profile, ~/.bash_profile, …); that can reset generic variables such as PATH and LD_LIBRARY_PATH, but the prelude runs last and is therefore the intended override point.

Preludes are workspace-local state: they do not travel with transfer. A job moved to another workspace runs under that workspace’s own preludes, so set the destination’s preludes there. See Project and workflow command line in detail for the full command reference.

The full guide, Task-manager usage in detail, covers workspace naming and defaults, submission forms, manager scheduling and capabilities, placement, requests, inspection and repair (fsck, gc, unlock), and the httk-taskmanager compatibility alias.