Use it when your goal in servers and infrastructure is clear and you can limit it to the data and actions it actually needs.
Modal
Serverless GPU cloud for ML jobs and model APIs
What does it add to Hermes?
Serverless GPU cloud for ML jobs and model APIs
Modal is a skill related to servers and infrastructure. It helps the agent understand or operate technical resources that can affect cost, availability, and security.
This plain-language explanation is based on the publisher description. The original text remains visible for verification.
Do not add it merely to experiment when Hermes already has a simpler path, or when you cannot review its source and permissions.
Best for users who want a repeatable way of working inside Hermes.
Start in a test environment with a limited account and inspect status before creating or deleting anything.
Serverless GPU cloud for ML jobs and model APIs
This entry was indexed from Hermes Optional Skills. Our explanation interprets the type and domain without inventing a capability not present upstream.
The source is official or editorially reviewed, but you still need to review permissions and version compatibility.
Inspect, install, then test.
- 01Open the source
Match the publisher, license, and description to your need. Check the real update history.
- 02Review permissions and secrets
Never paste a secret value into this site. Use environment-variable names and grant the smallest scope.
- 03Copy setup only after review
The controls below copy text. They do not execute commands on your device.
- 04Test with a non-sensitive task
Inspect the visible tools, then exclude write or delete tools you do not need.
Review the command, then copy it.
hermes skills install modalHermes Belarabi does not execute this command. Installation happens on your device and remains subject to Hermes scanning and your review.
Exactly what Hermes loads when this skill runs.
Reproduced from the official documentation. Read it before enabling the skill: this text becomes the agent's instructions.
Serverless GPU cloud for ML jobs and model APIs.
Skill metadata
A lookup table. Do not read it all; find the row that applies to you.
| Source | Optional — install with hermes skills install official/mlops/modal |
| Path | optional-skills/mlops/modal |
| Version | 1.0.1 |
| Author | Orchestra Research |
| License | MIT |
| Dependencies | modal>=1.0 |
| Platforms | linux, macos, windows |
| Tags | Infrastructure, Serverless, GPU, Cloud, Deployment, Modal |
Reference: full SKILL.md
Explains the idea itself. Read it slowly; the later sections build on it.
Guide to running ML workloads on Modal's serverless GPU cloud platform.
When to use Modal
Explains the idea itself. Read it slowly; the later sections build on it.
Use Modal when:
- Running GPU-intensive ML workloads without managing infrastructure
- Deploying ML models as auto-scaling APIs
- Running batch processing jobs (training, inference, data processing)
- Need pay-per-second GPU pricing without idle costs
- Prototyping ML applications quickly
- Running scheduled jobs (cron-like workloads)
Key features:
- Serverless GPUs: T4, L4, A10G, L40S, A100, H100, H200, B200 on-demand
- Python-native: Define infrastructure in Python code, no YAML
- Auto-scaling: Scale to zero, scale to 100+ GPUs instantly
- Sub-second cold starts: Rust-based infrastructure for fast container launches
- Container caching: Image layers cached for rapid iteration
- Web endpoints: Deploy functions as REST APIs with zero-downtime updates
Use alternatives instead:
- RunPod: For longer-running pods with persistent state
- Lambda Labs: For reserved GPU instances
- SkyPilot: For multi-cloud orchestration and cost optimization
- Kubernetes: For complex multi-service architectures
Quick start
Ordered, practical steps. Run one and confirm it worked before moving on.
Installation
pip install modal
modal setup # Opens browser for authenticationHello World with GPU
app = modal.App("hello-gpu")
@app.function(gpu="T4")
def gpu_info():
import subprocess
return subprocess.run(["nvidia-smi"], capture_output=True, text=True).stdout
@app.local_entrypoint()
def main():
print(gpu_info.remote())Run: modal run hello_gpu.py
Basic inference endpoint
app = modal.App("text-generation")
image = modal.Image.debian_slim().pip_install("transformers", "torch", "accelerate")
@app.cls(gpu="A10G", image=image)
class TextGenerator:
@modal.enter()
def load_model(self):
from transformers import pipeline
self.pipe = pipeline("text-generation", model="gpt2", device=0)
@modal.method()
def generate(self, prompt: str) -> str:
return self.pipe(prompt, max_length=100)[0]["generated_text"]
@app.local_entrypoint()
def main():
print(TextGenerator().generate.remote("Hello, world"))Core concepts
A lookup table. Do not read it all; find the row that applies to you.
Key components
| Component | Purpose |
|---|---|
App | Container for functions and resources |
Function | Serverless function with compute specs |
Cls | Class-based functions with lifecycle hooks |
Image | Container image definition |
Volume | Persistent storage for models/data |
Secret | Secure credential storage |
Execution modes
| Command | Description |
|---|---|
modal run script.py | Execute and exit |
modal serve script.py | Development with live reload |
modal deploy script.py | Persistent cloud deployment |
GPU configuration
A lookup table. Do not read it all; find the row that applies to you.
Available GPUs
| GPU | VRAM | Best For |
|---|---|---|
T4 | 16GB | Budget inference, small models |
L4 | 24GB | Inference, Ada Lovelace arch |
A10G | 24GB | Training/inference, 3.3x faster than T4 |
L40S | 48GB | Recommended for inference (best cost/perf) |
A100-40GB | 40GB | Large model training |
A100-80GB | 80GB | Very large models |
H100 | 80GB | Fastest, FP8 + Transformer Engine |
H200 | 141GB | Auto-upgrade from H100, 4.8TB/s bandwidth |
B200 | Latest | Blackwell architecture |
GPU specification patterns
# Single GPU
@app.function(gpu="A100")
# Specific memory variant
@app.function(gpu="A100-80GB")
# Multiple GPUs (up to 8)
@app.function(gpu="H100:4")
# GPU with fallbacks
@app.function(gpu=["H100", "A100", "L40S"])
# Any available GPU
@app.function(gpu="any")Container images
Explains the idea itself. Read it slowly; the later sections build on it.
# Basic image with pip
image = modal.Image.debian_slim(python_version="3.11").pip_install(
"torch==2.1.0", "transformers==4.36.0", "accelerate"
)
# From CUDA base
image = modal.Image.from_registry(
"nvidia/cuda:12.1.0-cudnn8-devel-ubuntu22.04",
add_python="3.11"
).pip_install("torch", "transformers")
# With system packages
image = modal.Image.debian_slim().apt_install("git", "ffmpeg").pip_install("whisper")Persistent storage
Explains the idea itself. Read it slowly; the later sections build on it.
volume = modal.Volume.from_name("model-cache", create_if_missing=True)
@app.function(gpu="A10G", volumes={"/models": volume})
def load_model():
import os
model_path = "/models/llama-7b"
if not os.path.exists(model_path):
model = download_model()
model.save_pretrained(model_path)
volume.commit() # Persist changes
return load_from_path(model_path)Web endpoints
A lookup table. Do not read it all; find the row that applies to you.
FastAPI endpoint decorator
@app.function()
@modal.fastapi_endpoint(method="POST")
def predict(text: str) -> dict:
return {"result": model.predict(text)}Full ASGI app
from fastapi import FastAPI
web_app = FastAPI()
@web_app.post("/predict")
async def predict(text: str):
return {"result": await model.predict.remote.aio(text)}
@app.function()
@modal.asgi_app()
def fastapi_app():
return web_appWeb endpoint types
| Decorator | Use Case |
|---|---|
@modal.fastapi_endpoint() | Simple function → API |
@modal.asgi_app() | Full FastAPI/Starlette apps |
@modal.wsgi_app() | Django/Flask apps |
@modal.web_server(port) | Arbitrary HTTP servers |
Dynamic batching
Explains the idea itself. Read it slowly; the later sections build on it.
@app.function()
@modal.batched(max_batch_size=32, wait_ms=100)
async def batch_predict(inputs: list[str]) -> list[dict]:
# Inputs automatically batched
return model.batch_predict(inputs)Secrets management
Explains the idea itself. Read it slowly; the later sections build on it.
# Create secret
modal secret create huggingface HF_TOKEN=hf_xxx@app.function(secrets=[modal.Secret.from_name("huggingface")])
def download_model():
import os
token = os.environ["HF_TOKEN"]Scheduling
Explains the idea itself. Read it slowly; the later sections build on it.
@app.function(schedule=modal.Cron("0 0 * * *")) # Daily midnight
def daily_job():
pass
@app.function(schedule=modal.Period(hours=1))
def hourly_job():
passPerformance optimization
Explains the idea itself. Read it slowly; the later sections build on it.
Cold start mitigation
# Modal 1.0 autoscaler params: scaledown_window (was container_idle_timeout).
# Input concurrency moved to the @modal.concurrent decorator.
@app.function(scaledown_window=300) # Keep warm 5 min
@modal.concurrent(max_inputs=10) # Handle concurrent requests per container
def inference():
passModel loading best practices
@app.cls(gpu="A100")
class Model:
@modal.enter() # Run once at container start
def load(self):
self.model = load_model() # Load during warm-up
@modal.method()
def predict(self, x):
return self.model(x)Parallel processing
Explains the idea itself. Read it slowly; the later sections build on it.
@app.function()
def process_item(item):
return expensive_computation(item)
@app.function()
def run_parallel():
items = list(range(1000))
# Fan out to parallel containers
results = list(process_item.map(items))
return resultsCommon configuration
Explains the idea itself. Read it slowly; the later sections build on it.
@app.function(
gpu="A100",
memory=32768, # 32GB RAM
cpu=4, # 4 CPU cores
timeout=3600, # 1 hour max
scaledown_window=120, # Keep warm 2 min (was container_idle_timeout)
retries=3, # Retry on failure
max_containers=10, # Max concurrent containers (was concurrency_limit)
min_containers=1, # Keep N containers warm (was keep_warm)
)
def my_function():
passModal 1.0 autoscaler renames (see the migration guide ↗): -container_idle_timeout→scaledown_window-concurrency_limit→max_containers-keep_warm→min_containers-allow_concurrent_inputs=N→ the@modal.concurrent(max_inputs=N)decorator
Debugging
A troubleshooting section. Find the symptom that matches yours rather than reading it end to end.
# Test locally
if __name__ == "__main__":
result = my_function.local()
# View logs
# modal app logs my-appCommon issues
A lookup table. Do not read it all; find the row that applies to you.
| Issue | Solution |
|---|---|
| Cold start latency | Increase scaledown_window, use @modal.enter() |
| GPU OOM | Use larger GPU (A100-80GB), enable gradient checkpointing |
| Image build fails | Pin dependency versions, check CUDA compatibility |
| Timeout errors | Increase timeout, add checkpointing |
References
Explains the idea itself. Read it slowly; the later sections build on it.
- Advanced Usage ↗ - Multi-GPU, distributed training, cost optimization
- Troubleshooting ↗ - Common issues and solutions
Resources
Explains the idea itself. Read it slowly; the later sections build on it.
- Documentation: https://modal.com/docs
- Examples: https://github.com/modal-labs/modal-examples
- Pricing: https://modal.com/pricing
- Discord: https://discord.gg/modal