Best Practices for Networking in AWS SageMaker

Best Practices for Networking in AWS SageMaker

Amazon SageMaker is a fully managed machine learning service that enables data scientists and developers to build, train, and deploy ML models at scale. While SageMaker simplifies many aspects of the ML workflow, proper network configuration is critical for security, compliance, and performance. This article explores best practices for networking in AWS SageMaker environments.

Understanding SageMaker Network Architecture

SageMaker resources can operate in two modes: internet-facing or VPC-isolated. Understanding these modes is fundamental to implementing proper network security.

Internet-Facing vs. VPC Mode

By default, SageMaker notebook instances, training jobs, and endpoints are created with direct internet access. While convenient for getting started, this approach may not meet security requirements for production workloads. VPC mode places SageMaker resources within your Virtual Private Cloud, giving you complete control over network access.

VPC Configuration Best Practices

Use Private Subnets

Always deploy SageMaker resources in private subnets rather than public ones. Private subnets prevent direct internet access to your ML infrastructure, reducing the attack surface significantly.

import boto3

sagemaker = boto3.client('sagemaker')

response = sagemaker.create_notebook_instance(
    NotebookInstanceName='my-secure-notebook',
    InstanceType='ml.t3.medium',
    SubnetId='subnet-xxxxx',  # Private subnet ID
    SecurityGroupIds=['sg-xxxxx'],
    DirectInternetAccess='Disabled',
    RoleArn='arn:aws:iam::account-id:role/SageMakerRole'
)
Creating a SageMaker notebook instance in a private subnet

Implement Multiple Availability Zones

For production workloads, especially SageMaker endpoints serving real-time inference, distribute resources across multiple Availability Zones (AZs). This ensures high availability and fault tolerance.

Network Isolation for Training Jobs

SageMaker training jobs should run in network isolation mode when dealing with sensitive data. This prevents the training container from making outbound network calls.

import boto3

sagemaker_client = boto3.client('sagemaker')

response = sagemaker_client.create_training_job(
    TrainingJobName='my-isolated-training-job',
    RoleArn='arn:aws:iam::account-id:role/SageMakerRole',
    AlgorithmSpecification={
        'TrainingImage': 'my-training-image',
        'TrainingInputMode': 'File'
    },
    ResourceConfig={
        'InstanceType': 'ml.p3.2xlarge',
        'InstanceCount': 1,
        'VolumeSizeInGB': 50
    },
    VpcConfig={
        'Subnets': ['subnet-xxxxx'],
        'SecurityGroupIds': ['sg-xxxxx']
    },
    EnableNetworkIsolation=True,
    StoppingCondition={
        'MaxRuntimeInSeconds': 86400
    },
    OutputDataConfig={
        'S3OutputPath': 's3://my-bucket/output'
    }
)
Enabling network isolation for SageMaker training jobs

Security Groups and NACLs

Principle of Least Privilege

Configure security groups with the minimum required permissions. For SageMaker notebook instances, typically only HTTPS (port 443) needs to be allowed inbound for Jupyter access through the AWS console.

Inbound Rules:
- Type: HTTPS
- Protocol: TCP
- Port: 443
- Source: Your VPC CIDR or specific IP ranges

Outbound Rules:
- Allow necessary AWS service endpoints
- Block all other traffic by default

Separate Security Groups by Function

Create distinct security groups for different SageMaker components:

Security Group TypePurpose
Notebook Security GroupFor development and experimentation
Training Security GroupFor training jobs
Endpoint Security GroupFor model serving
Data Source Security GroupFor databases and data storage

This separation enables fine-grained control and simplifies troubleshooting.

Use Network ACLs as a Second Layer

While security groups provide instance-level security, Network ACLs (NACLs) offer subnet-level protection. Implement NACLs as an additional defense layer, especially for subnets hosting production endpoints.

VPC Endpoints for AWS Services

Why VPC Endpoints Matter

VPC endpoints allow SageMaker resources to communicate with AWS services without traversing the public internet. This improves security, reduces latency, and can lower data transfer costs.

Essential VPC Endpoints for SageMaker

Create the following VPC endpoints in your VPC:

Endpoint TypePurpose
S3 Gateway EndpointFor accessing training data and model artifacts
SageMaker API EndpointFor SageMaker service API calls
SageMaker Runtime EndpointFor inference requests to endpoints
CloudWatch Logs EndpointFor logging and monitoring
ECR API and DKR EndpointsFor pulling custom container images
STS EndpointFor assuming IAM roles
aws ec2 create-vpc-endpoint \
    --vpc-id vpc-xxxxx \
    --service-name com.amazonaws.us-east-1.s3 \
    --route-table-ids rtb-xxxxx
Creating an S3 gateway endpoint

Interface Endpoints Configuration

For interface endpoints (like SageMaker API), ensure they're deployed across multiple AZs and associated with appropriate security groups:

aws ec2 create-vpc-endpoint \
    --vpc-id vpc-xxxxx \
    --vpc-endpoint-type Interface \
    --service-name com.amazonaws.us-east-1.sagemaker.api \
    --subnet-ids subnet-xxxxx subnet-yyyyy \
    --security-group-ids sg-xxxxx
Creating a SageMaker API interface endpoint

DNS Resolution and Private Hosted Zones

Enable DNS Resolution

Ensure that your VPC has DNS resolution and DNS hostnames enabled. This is required for VPC endpoints to function correctly.

aws ec2 modify-vpc-attribute \
    --vpc-id vpc-xxxxx \
    --enable-dns-support

aws ec2 modify-vpc-attribute \
    --vpc-id vpc-xxxxx \
    --enable-dns-hostnames
Enabling DNS resolution and hostnames in VPC

Private Hosted Zones

For custom endpoints or when integrating with on-premises resources, use Route 53 private hosted zones to manage DNS resolution within your VPC.

Data Encryption in Transit

Enforce TLS for All Communications

Always use TLS encryption for data in transit. SageMaker supports TLS 1.2 and higher for all API calls and notebook access.

VPN or Direct Connect for Hybrid Environments

If your ML workflow involves on-premises data sources, establish secure connectivity using AWS VPN or Direct Connect rather than transmitting data over the public internet.

Monitoring and Logging

VPC Flow Logs

Enable VPC Flow Logs to capture network traffic metadata. This is invaluable for security analysis, compliance auditing, and troubleshooting network issues.

aws ec2 create-flow-logs \
    --resource-type VPC \
    --resource-ids vpc-xxxxx \
    --traffic-type ALL \
    --log-destination-type cloud-watch-logs \
    --log-group-name /aws/vpc/flowlogs
Creating VPC Flow Logs for network monitoring

CloudWatch Metrics

Monitor SageMaker-specific metrics alongside network metrics:

  • Endpoint invocation latency
  • Model container CPU/memory utilization
  • Training job network throughput
  • Failed API calls

AWS Config Rules

Implement AWS Config rules to ensure network configurations remain compliant:

  • Verify SageMaker notebooks are in VPCs
  • Confirm network isolation is enabled for training jobs
  • Validate security group configurations

Cost Optimization

Use S3 Gateway Endpoints

S3 gateway endpoints are free and eliminate data transfer charges for S3 access within the same region. This can result in significant cost savings for data-intensive ML workloads.

Right-Size VPC Endpoints

Interface endpoints incur hourly charges and data processing fees. Only create endpoints for services you actually use, and share endpoints across workloads when possible.

NAT Gateway Optimization

If you need internet access for certain operations (like installing packages), use NAT Gateways judiciously:

  • Share NAT Gateways across multiple private subnets
  • Consider NAT instances for dev/test environments
  • Use VPC endpoints instead of NAT for AWS service access

Compliance and Governance

Network Segmentation

Segregate different environments (dev, staging, production) into separate VPCs or subnets. This prevents cross-contamination and simplifies compliance controls.

Tagging Strategy

Implement a comprehensive tagging strategy for all network resources:

Environment: Production
Project: ML-Pipeline
Owner: DataScience-Team
CostCenter: ML-Operations
Compliance: HIPAA

When integrating with third-party ML tools or data sources, use AWS PrivateLink to maintain private connectivity without exposing your VPC to the internet.

Troubleshooting Common Network Issues

Connection Timeouts

If SageMaker resources can't reach required services:

  1. Verify security group rules allow outbound traffic
  2. Confirm route tables direct traffic correctly
  3. Check VPC endpoint configuration and policies
  4. Validate IAM role permissions

DNS Resolution Failures

If DNS isn't resolving for VPC endpoints:

  1. Ensure DNS resolution is enabled in the VPC
  2. Verify private DNS is enabled for interface endpoints
  3. Check DHCP options sets are correct

Performance Issues

If experiencing slow data transfer or inference latency:

  1. Review VPC endpoint placement across AZs
  2. Check for cross-AZ data transfer
  3. Validate network bandwidth isn't saturated
  4. Consider using Enhanced Networking for EC2-based components

Example: Secure Production Architecture

Here's a complete example of a secure SageMaker architecture:

import boto3
from sagemaker import Session, get_execution_role
ec2 = boto3.client('ec2')
sagemaker_client = boto3.client('sagemaker')

# VPC Configuration
vpc_id = 'vpc-xxxxx'
private_subnet_1 = 'subnet-aaaaa'  # us-east-1a
private_subnet_2 = 'subnet-bbbbb'  # us-east-1b

# Security Groups
training_sg = 'sg-training'
endpoint_sg = 'sg-endpoint'

# Create VPC Endpoints
endpoints = [
    'com.amazonaws.us-east-1.sagemaker.api',
    'com.amazonaws.us-east-1.sagemaker.runtime',
    'com.amazonaws.us-east-1.ecr.api',
    'com.amazonaws.us-east-1.ecr.dkr',
    'com.amazonaws.us-east-1.s3',
    'com.amazonaws.us-east-1.logs'
]

# Training job with network isolation
sagemaker = Session()
role = get_execution_role()

from sagemaker.estimator import Estimator

estimator = Estimator(
    image_uri='my-secure-training-image',
    role=role,
    instance_count=2,
    instance_type='ml.p3.2xlarge',
    volume_size=100,
    subnets=[private_subnet_1, private_subnet_2],
    security_group_ids=[training_sg],
    enable_network_isolation=True,
    encrypt_inter_container_traffic=True
)

# Deploy model with VPC configuration
predictor = estimator.deploy(
    initial_instance_count=2,
    instance_type='ml.m5.xlarge',
    endpoint_name='secure-ml-endpoint',
    vpc_config={
        'Subnets': [private_subnet_1, private_subnet_2],
        'SecurityGroupIds': [endpoint_sg]
    }
)
Complete secure production SageMaker architecture

Conclusion

Proper networking configuration is essential for secure, compliant, and performant SageMaker deployments. By following these best practices—using private subnets, implementing VPC endpoints, configuring security groups correctly, and enabling comprehensive monitoring—you can build ML infrastructure that meets enterprise security requirements while maintaining the agility needed for rapid model development and deployment.

Remember that network architecture should evolve with your ML operations maturity. Start with basic VPC isolation for development, then progressively add more sophisticated controls as you move toward production. Regular security audits and configuration reviews ensure your network remains secure as your ML workloads grow and change.

Additional Resources