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Vast.ai On-Demand GPU Integration
🇨🇳 中文版:VAST_GPU_GUIDE_CN.md Part of the ARIS GPU Server Setup options. Use this when you don't own a GPU server.
ARIS supports renting GPUs on demand from Vast.ai — the cheapest spot-rental marketplace for ML hardware. When you run /run-experiment, ARIS analyzes your training task (model size, dataset, estimated time), searches for the cheapest GPU that fits the workload, and presents options ranked by estimated total cost (not just $/hr). After you pick, it handles everything: rent → setup → run → collect results → destroy.
When to use this vs. gpu: remote / gpu: local
| Option | When | Cost model |
|---|---|---|
gpu: remote |
You own (or your lab provides) a fixed SSH-accessible server | Sunk cost; ARIS treats it as free |
gpu: local |
You're already on the GPU host | Sunk cost; no SSH overhead |
gpu: vast |
No GPU, or you need bigger hardware than what you own for one experiment | Per-hour rental, auto-billed by Vast.ai |
Vast.ai works for one-off ablations, baseline reruns, or scaling up to A100/H100 for a single experiment. Not ideal for week-long training jobs — at that point a dedicated server is cheaper.
Prerequisites
-
Create a Vast.ai account at https://cloud.vast.ai/ and add billing (credit card or crypto).
-
Install the
vastaiCLI (requires Python ≥ 3.10):pip install vastaiIf your Python is older (check with
python --version), use a virtual environment with Python ≥ 3.10 (e.g.,conda create,pyenv,uv venv). -
Set your API key — get it from https://cloud.vast.ai/cli/:
vastai set api-key YOUR_API_KEY -
Upload your SSH public key at https://cloud.vast.ai/manage-keys/ — this is required before renting any instance (keys are baked in at creation time). If you don't have one:
ssh-keygen -t ed25519 -C "your_email@example.com" cat ~/.ssh/id_ed25519.pub # copy this to Vast.ai -
Verify setup — test that search works:
vastai search offers 'gpu_ram>=24 reliability>0.95' -o 'dph+' --limit 3
Tell ARIS to use Vast.ai
Add to your project's CLAUDE.md:
## Vast.ai
- gpu: vast # rent on-demand GPU from vast.ai
- auto_destroy: true # auto-destroy after experiment completes (default)
- max_budget: 5.00 # optional: warn if estimated cost exceeds this
That's it — no GPU model or hardware config needed. ARIS reads your experiment scripts/plan, estimates VRAM and training time, then presents options:
| # | GPU | VRAM | $/hr | Est. Hours | Est. Total | Offer ID |
|---|-----------|-------|-------|------------|------------|----------|
| 1 | RTX 4090 | 24 GB | $0.28 | ~4h | ~$1.12 | 6995713 | ← best value
| 2 | A100 SXM | 80 GB | $0.95 | ~2h | ~$1.90 | 7023456 | ← fastest
Pick a number and ARIS handles the rest.
Manual control
For one-off rentals outside the /run-experiment flow, use the dedicated skill:
/vast-gpu # interactive — search, pick, rent
/vast-gpu list # list your current rented instances
/vast-gpu destroy <instance-id> # tear down manually
auto_destroy: true will tear instances down after /run-experiment finishes; false leaves them up so you can SSH in and inspect. Always run vastai show instances (or /vast-gpu list) after a session to confirm nothing is silently billing you.
Cost expectations
Typical ARIS workloads with Vast.ai:
- Small ablation (single-GPU, 1–4 hours): ~$0.30 – $2 / run on RTX 3090/4090
- Bigger baseline rerun (40–80 GB VRAM, multi-hour): ~$2 – $10 / run on A100/H100
- Spot-prices fluctuate;
vastai search offersreflects live market rates
Set max_budget in CLAUDE.md to get a warning when ARIS's estimate exceeds your comfort zone — it doesn't hard-block, just confirms before renting.
Fallback: no server at all
The review and rewriting skills (/auto-review-loop, /research-review, /paper-writing, /paper-compile) still work without GPU access. Only experiment-related fixes will be skipped (flagged for manual follow-up).
Related skills
/vast-gpu— direct rental control/run-experiment— auto-deploy viagpu: vast/monitor-experiment— collect results from running rentals