Model Deployment

Overview

Model deployment is the process of taking a trained machine learning model and making it available for production use through APIs, web services, or batch processing systems.

When to Use

• When productionizing trained models for real-world inference and predictions
• When building REST APIs or web services for model serving
• When scaling predictions to serve multiple users or applications
• When deploying models to cloud platforms, edge devices, or containers
• When implementing CI/CD pipelines for ML model updates
• When creating batch processing systems for large-scale predictions

Deployment Approaches

• REST APIs: Flask, FastAPI for synchronous inference
• Batch Processing: Scheduled jobs for large-scale predictions
• Real-time Streaming: Kafka, Spark Streaming for continuous data
• Serverless: AWS Lambda, Google Cloud Functions
• Edge Deployment: TensorFlow Lite, ONNX for edge devices
• Model Serving: TensorFlow Serving, Seldon Core, BentoML

Key Considerations

• Model Format: Pickle, SavedModel, ONNX, PMML
• Scalability: Load balancing, auto-scaling
• Latency: Response time requirements
• Monitoring: Model drift, performance metrics
• Versioning: Multiple model versions in production

Python Implementation

import numpy as np
import pandas as pd
import pickle
import json
from sklearn.ensemble import RandomForestClassifier
from sklearn.preprocessing import StandardScaler
from sklearn.datasets import make_classification
import joblib

# FastAPI for REST API
from fastapi import FastAPI, HTTPException, BackgroundTasks
from pydantic import BaseModel, Field
import uvicorn

# For model serving
import mlflow.pyfunc
import mlflow.sklearn

# Docker and deployment
import logging
import time
from typing import List, Dict

# Configure logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

print("=== 1. Train and Save Model ===")

# Create dataset
X, y = make_classification(n_samples=1000, n_features=20, random_state=42)
scaler = StandardScaler()
X_scaled = scaler.fit_transform(X)

# Train model
model = RandomForestClassifier(n_estimators=100, max_depth=10, random_state=42)
model.fit(X_scaled, y)

# Save model and preprocessing
model_path = '/tmp/model.pkl'
scaler_path = '/tmp/scaler.pkl'

joblib.dump(model, model_path)
joblib.dump(scaler, scaler_path)

print(f"Model saved to {model_path}")
print(f"Scaler saved to {scaler_path}")

# 2. Model Serving Class
print("\n=== 2. Model Serving Class ===")

class ModelPredictor:
    def __init__(self, model_path, scaler_path):
        self.model = joblib.load(model_path)
        self.scaler = joblib.load(scaler_path)
        self.load_time = time.time()
        self.predictions_count = 0
        logger.info("Model loaded successfully")

    def predict(self, features: List[List[float]]) -> Dict:
        try:
            X = np.array(features)
            X_scaled = self.scaler.transform(X)
            predictions = self.model.predict(X_scaled)
            probabilities = self.model.predict_proba(X_scaled)

            self.predictions_count += len(X)

            return {
                'predictions': predictions.tolist(),
                'probabilities': probabilities.tolist(),
                'count': len(X),
                'timestamp': time.time()
            }
        except Exception as e:
            logger.error(f"Prediction error: {str(e)}")
            raise

    def health_check(self) -> Dict:
        return {
            'status': 'healthy',
            'uptime': time.time() - self.load_time,
            'predictions': self.predictions_count
        }

# Initialize predictor
predictor = ModelPredictor(model_path, scaler_path)

# 3. FastAPI Application
print("\n=== 3. FastAPI Application ===")

app = FastAPI(
    title="ML Model API",
    description="Production ML model serving API",
    version="1.0.0"
)

class PredictionRequest(BaseModel):
    features: List[List[float]] = Field(..., example=[[1.0, 2.0, 3.0]])

class PredictionResponse(BaseModel):
    predictions: List[int]
    probabilities: List[List[float]]
    count: int
    timestamp: float

class HealthResponse(BaseModel):
    status: str
    uptime: float
    predictions: int

@app.get("/health", response_model=HealthResponse)
async def health_check():
    """Health check endpoint"""
    return predictor.health_check()

@app.post("/predict", response_model=PredictionResponse)
async def predict(request: PredictionRequest):
    """Make predictions"""
    try:
        result = predictor.predict(request.features)
        return result
    except Exception as e:
        raise HTTPException(status_code=400, detail=str(e))

@app.post