ramjetio 0.11.2

Distributed peer cache for ML training data — works with any framework on any S3-compatible store

RAMJET — Distributed peer cache for ML training data

RAMJET is a peer-to-peer cache between any ML training job and any S3-compatible object store. The first run pulls data from S3 once and seeds the cluster; subsequent runs across the team serve every sample peer-to-peer with zero S3 calls.

Works with any framework that loads data from S3/HTTP/local paths — PyTorch, TensorFlow, JAX, HuggingFace Datasets, Ultralytics, custom loaders — and any DDP launcher (torchrun, DeepSpeed, Accelerate, SLURM).

Measured on a real 2× A5000 cluster (5315 samples, 5 epochs): 6.5× faster export when cache is warm, zero S3 requests after the first run.

Why RAMJET?

Problem	Solution
Repeated S3 pulls across team experiments	One pull seeds the cluster; the rest serve peer-to-peer
Network bottleneck from shared object storage	Local SSD cache on every training node
No visibility into data-loading bottlenecks	Live dashboard with per-node bytes-by-source split (local / peer / S3) and Grafana-native Prometheus metrics
Multi-node DDP coordination	Auto-detect rank/world size from torchrun/SLURM env

Quick Start

1. Install

pip install ramjetio

2. Add to Your Training Script

import ramjetio
from torch.utils.data import DataLoader

ramjetio.init()

dataset = ramjetio.CachedDataset(your_dataset)
loader = DataLoader(dataset, batch_size=32)

for batch in loader:
    train_step(batch)

3. Run

Get your API key from app.ramjet.io (create a cluster → copy key).

export RAMJET_API_KEY="your_api_key_here"
python train.py

Multi-GPU: torchrun --nproc_per_node=N train.py

That's it! Your nodes will appear in the dashboard within seconds.

How It Works

   ┌──────────┐   ┌──────────┐   ┌──────────┐
   │  Node 0  │   │  Node 1  │   │  Node 2  │
   │  train   │   │  train   │   │  train   │
   │    │     │   │    │     │   │    │     │
   │    ▼     │   │    ▼     │   │    ▼     │
   │ ramjetio │◄─►│ ramjetio │◄─►│ ramjetio │
   │  cache   │   │  cache   │   │  cache   │
   │ NVMe SSD │   │ NVMe SSD │   │ NVMe SSD │
   └─────┬────┘   └─────┬────┘   └─────┬────┘
         └──────────────┼──────────────┘
                        ▼
                ┌───────────────┐
                │ S3 / MinIO /  │
                │ R2 / GCS / …  │
                └───────────────┘

   Hits stay local or hop to a peer (sub-ms over LAN).
   Only the first miss in the cluster ever touches object storage.

Features

• 🚀 Zero-config caching — ramjetio.init() handles everything
• 📊 Real-time dashboard — monitor cache hits, throughput, GPU utilization
• 🔄 Consistent hashing — data distributed evenly across nodes
• 💾 Disk-backed cache — survives restarts, uses NVMe SSDs efficiently
• 🔌 Works with any setup — torchrun, DeepSpeed, Accelerate, custom launchers
• ☁️ S3/MinIO integration — configure data source in dashboard, not in code

Integration Examples

Runnable scripts in examples/:

• simple.py — minimal end-to-end starting point
• pytorch_imagenet.py — ImageFolder + ResNet18 + CachedDataset
• huggingface_datasets.py — datasets.load_dataset(...) wrapped with cache
• yolov8.py — Ultralytics YOLOv8 via UniversalDataset(format='yolo')
• torchrun_ddp.py — multi-node DDP under torchrun
• accelerate_example.py — HuggingFace Accelerate
• deepspeed_example.py — DeepSpeed launcher
• ddp_torchrun.sh — one-liner torchrun wrapper (auto-detects GPUs)

See docs/INTEGRATION.md for deeper walkthroughs.

Configuration

Environment Variables

Variable	Description	Default
RAMJET_API_KEY	Your API key (required)	—
RAMJET_CACHE_PATH	Local cache directory	/tmp/ramjet_cache
RAMJET_CACHE_SIZE	Max cache size	100GB
RAMJET_PORT	Cache server port	9000
RAMJET_STORE	Local store backend: diskcache (default) or lmdb (opt-in, ~15× faster GET p50 on warm reads; see docs/STORE.md)	diskcache
OTEL_EXPORTER_OTLP_ENDPOINT	OTLP collector endpoint. When set (and ramjetio[otel] is installed), enables distributed tracing across SDK → peer → backend. See docs/TRACING.md.	(unset, tracing disabled)
RAMJET_TRACE_SAMPLE	Trace sampling ratio (0.0–1.0). Only meaningful when tracing is enabled.	1.0

Dashboard Settings

Configure in the web dashboard (no code changes needed):

• Data Source: S3/MinIO endpoint, bucket, credentials
• Cache Settings: TTL, replication factor, eviction policy

Distributed Training (DDP)

RAMJET automatically detects torchrun and DDP environments:

Single Machine, Multiple GPUs (torchrun)

# 4 GPUs on one machine
torchrun --nproc_per_node=4 train.py

import ramjetio
import torch.distributed as dist

# Only LOCAL_RANK=0 starts cache server - others wait and share it
ramjetio.init()

# All ranks use the same cache
dataset = ramjetio.CachedDataset(your_dataset)

Multi-Node Training

RAMJET auto-detects your cluster manager — no manual configuration needed:

Environment	How to launch	RAMJET detects it?
SLURM	srun python train.py	✅ Automatic
Kubernetes (PyTorchJob)	Managed by operator	✅ Automatic
DeepSpeed	deepspeed --hostfile hosts train.py	✅ Automatic
Accelerate	accelerate launch train.py	✅ Automatic
torchrun	torchrun --nproc_per_node=N train.py	✅ Automatic
SageMaker	Configured in SageMaker console	✅ Automatic

Each node runs one cache server (on LOCAL_RANK=0), and all nodes share data via consistent hashing. RAMJET reads LOCAL_RANK, RANK, WORLD_SIZE from environment — every major launcher sets these automatically.

CLI Tools

# Start cache server manually (usually not needed — ramjetio.init() does this)
ramjetio-server --port 9000 --capacity 100GB

# Check cache status
ramjetio-client stats

# Clear cache
ramjetio-client clear

Requirements

• Python 3.8+
• PyTorch 1.9+
• Linux (recommended for production)
• SSD storage for cache (recommended)

Documentation

• Integration Guide — detailed examples for all frameworks
• API Reference — full API documentation
• Troubleshooting — common issues and solutions

License

PolyForm Noncommercial License 1.0.0 — free for personal and non-commercial use. For commercial licensing, contact [e-mail]. See LICENSE for details.

Support

• 📧 Email: [e-mail]
• 💬 Discord: discord.gg/ramjet
• 📖 Docs: docs.ramjet.io