MCP RDS Jumphost

Secure Claude Code connection to RDS PostgreSQL via AWS Session Manager port forwarding.

This repository demonstrates how to set up a secure, private RDS PostgreSQL database that Claude Code can query through an MCP (Model Context Protocol) server, without exposing any public endpoints.

Architecture

┌─────────────────────────────────────────────────────────────────────────────┐
│                                   AWS VPC                                   │
│                          (Private Isolated Subnets)                         │
│                                                                             │
│  ┌─────────────────────────────────────────────────────────────────────┐   │
│  │                        VPC Endpoints                                 │   │
│  │              (ssm, ssmmessages, ec2messages)                        │   │
│  └─────────────────────────────────────────────────────────────────────┘   │
│                                    │                                        │
│                                    │ HTTPS (443)                            │
│                                    ▼                                        │
│  ┌──────────────────────┐    ┌──────────────────────┐                      │
│  │   EC2 Jumphost       │    │   RDS PostgreSQL     │                      │
│  │   (t4g.micro)        │───▶│   (db.t4g.micro)     │                      │
│  │                      │5432│                      │                      │
│  │   - Amazon Linux 2023│    │   - PostgreSQL 16    │                      │
│  │   - SSM Agent        │    │   - Encrypted        │                      │
│  │   - No SSH Key       │    │   - Private only     │                      │
│  └──────────────────────┘    └──────────────────────┘                      │
│            ▲                                                                │
│            │ SSM Session Manager                                            │
│            │ Port Forwarding                                                │
└────────────┼────────────────────────────────────────────────────────────────┘
             │
             │
┌────────────┼────────────────────────────────────────────────────────────────┐
│            │                    Local Machine                               │
│            ▼                                                                │
│  ┌──────────────────────┐    ┌──────────────────────┐                      │
│  │   SSM Tunnel         │    │   MCP Server         │                      │
│  │   localhost:5432 ────┼───▶│   (@mcp/postgres)    │                      │
│  └──────────────────────┘    └──────────────────────┘                      │
│                                       │                                     │
│                                       ▼                                     │
│                              ┌──────────────────────┐                      │
│                              │   Claude Code        │                      │
│                              │   (queries DB)       │                      │
│                              └──────────────────────┘                      │
└─────────────────────────────────────────────────────────────────────────────┘

Prerequisites

Quick Start

1. Clone and Install

git clone https://github.com/your-org/mcp-rds-jumphost.git
cd mcp-rds-jumphost
pnpm install

2. Deploy Infrastructure

# Bootstrap CDK (first time only)
pnpm cdk bootstrap

# Deploy the stack
pnpm cdk deploy

3. Seed the Database (Optional)

In a separate terminal, start the tunnel and seed the database:

# Terminal 1: Start the tunnel
./scripts/tunnel.sh

# Terminal 2: Run seed script
./scripts/seed.sh

4. Use with Claude Code

Open Claude Code in the project directory. The .mcp.json is already configured. The MCP server will connect automatically when you ask database-related questions.

Example Prompts

Try these prompts with Claude Code:

• "List all authors in the database"
• "Show me all posts with their author names"
• "How many posts does each author have?"
• "Find posts published in 2024 sorted by date"
• "What's the schema of the posts table?"

Scripts

scripts/tunnel.sh

Starts an SSM tunnel to the RDS database (runs in foreground).

Usage:

./scripts/tunnel.sh [STACK_NAME] [LOCAL_PORT]
# Defaults: McpRdsJumphostStack, 5432

scripts/mcp-postgres.sh

Combined script that:

1. Validates prerequisites (SSM plugin, AWS CLI, jq)
2. Fetches CloudFormation outputs
3. Retrieves database credentials from Secrets Manager
4. Starts SSM tunnel in background
5. Launches MCP PostgreSQL server

Usage:

./scripts/mcp-postgres.sh [STACK_NAME] [LOCAL_PORT]
# Defaults: McpRdsJumphostStack, 5432

scripts/seed.sh

Seeds the database with sample blog data (5 authors, 15 posts).

Usage:

./scripts/seed.sh [STACK_NAME] [LOCAL_PORT]

Requires: Active tunnel on the specified port and psql client installed.

Security

• All resources in private isolated subnets, no public IPs
• No SSH keys — access via Session Manager only
• SSM connectivity through private VPC endpoints
• RDS storage encrypted at rest
• Database credentials stored in Secrets Manager
• RDS only accepts connections from the jumphost security group

Cost Estimate

Running this infrastructure costs approximately ~$40/month:

Important: Remember to destroy the stack when not in use to avoid ongoing charges. VPC endpoints are particularly costly if left running.

Cleanup

To delete all resources and stop incurring costs:

pnpm cdk destroy

This will remove:

• VPC and all subnets
• VPC Endpoints
• EC2 jumphost
• RDS instance (data will be lost)
• Security groups
• IAM roles
• Secrets Manager secret

Project Structure

mcp-rds-jumphost/
├── bin/
│   └── mcp-rds-jumphost.ts    # CDK app entry point
├── lib/
│   └── mcp-rds-jumphost-stack.ts  # Main CDK stack
├── scripts/
│   ├── tunnel.sh              # SSM tunnel to RDS
│   ├── mcp-postgres.sh        # MCP server launcher
│   └── seed.sh                # Database seeder
├── .mcp.json                     # MCP server configuration
├── package.json
├── tsconfig.json
├── cdk.json
└── README.md

License

MIT License - see LICENSE for details.