Improve OpenShell Support for HPC-style Shared Compute Environments

Problem Statement

Summary

This umbrella issue tracks a set of related feature requests to make OpenShell easier to deploy in HPC-style shared compute environments.

The common theme is support for locked-down Linux hosts, shared filesystems, scheduler-managed jobs, narrow internal network access, and daemonless runtime options.

This umbrella supersedes #1393. #1393 raised the general problem of HPC-style hosts being a poor fit for Docker/Podman/MicroVM/Kubernetes. The work is concrete and each runtime can be evaluated, accepted, or dropped on its own merits.

Motivation

Many HPC environments differ from cloud-native environments:

• shared filesystems are central to the workflow,
• tools and datasets are often installed outside the sandbox image,
• users may not have admin privileges,
• compute nodes may not run Docker or Kubernetes,
• network egress is often restricted,
• batch schedulers manage job lifecycle,
• workloads may need fast startup and low runtime overhead.

OpenShell has a strong policy, gateway, credential, and supervision model, but these environments need additional runtime and storage support.

Proposed Design

Child issues

1. #1746 — First-class shared filesystem mounts for HPC sandboxes
2. #1747 — Raw TCP allowlists for internal HPC services
3. #1748 — Filesystem policy enforcement on shared-mounted paths (incl. user-identity / UID-GID model)
4. #1393 — Bubblewrap/Apptainer-backed runtime mode for daemonless HPC hosts

Desired outcome

OpenShell should be able to run automated or agentic workloads on traditional HPC/shared compute infrastructure while preserving least-privilege policy enforcement, credential mediation, network controls, and auditability.

Alternatives Considered

N/A

Agent Investigation

No response

Checklist

• I've reviewed existing issues and the architecture docs
• This is a design proposal, not a "please build this" request

Start by reading child issues #1746, #1747, and #1748, then compare their scopes with the superseded #1393. The issue is an umbrella design proposal rather than a standalone implementation task; done means evaluating the child runtime, filesystem, and networking requests while preserving policy enforcement, credential mediation, auditability, and least privilege.