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Part of CALC@HEI, the HEI research computing infrastructure — governance in transition, currently operated by the ISC staff.

Using CALC@HEI

Welcome to CALC@HEI, the HEI research computing infrastructure.

We are currently test driving a strategy for mutualizing computational resources within HEI. The current policy is therefore designed to be temporary and will evolve as we understand better the usage patterns and requirements of various users.

The project is expected to have three phases, which are subject to change:

  • Initial phase (until March 2025): we run a best-effort, priority-less offering. The goal of this phase is to test-drive some of the tools we use (Slurm, Apptainer, etc.), estimate the demand and requirements from users, and collect data on usage patterns, e.g., periods of congestion and overall usage ratio.
  • Expansion phase (April-July 2025): we introduce priorities based on investments and projects' criticality and we stabilize the toolchain, with an improved documentation and more formal support to the users. We formalize and possibly extend the scope of the offering to more research labs and institutes within HEI.
  • Exploitation (August 2025-onwards): depending on the success of earlier phases, we introduce service-level agreements (SLA) and a tarification for users to contribute financially to the platform based on their usage patterns.

Rules of the game​

The following rules apply in this initial phase of the project:

  • All users must submit Apptainer jobs via SLURM. To run a job on our infrastructure here is the process : How to run a job on our computational ressources
  • Users are expected to search for solutions and contribute to the documentation whenever possible. Remember that this is a best-effort service without any guarantee of availability and/or support.
  • There is a limited prioritization: in the future, users will be assigned tokens depending on criteria to be approved by the steering committee. During the initial phase, a manual tuning will be performed. Please note that we don't really expect this constraint to be a problem, as the current number of users is limited.

Where to go next​

  1. Requesting access — who to contact and what to prepare
  2. Connecting — SSH to the compute nodes
  3. Submitting jobs — the full workflow, from container to results
  4. SLURM job examples — serial, MPI, GPU, interactive
  5. Building Apptainer containers — package your environment
  6. Storage and quotas — where to put data, and for how long
  7. FAQ — common questions and pitfalls

The machines themselves — Chacha, Disco and the SLURM configuration — are described in the CALC@HEI overview.