Source: wshobson/agents Original Plugin: cloud-infrastructure

Hybrid Cloud Networking

Configure secure, high-performance connectivity between on-premises and cloud environments using VPN, Direct Connect, and ExpressRoute.

Purpose

Establish secure, reliable network connectivity between on-premises data centers and cloud providers (AWS, Azure, GCP).

When to Use

Connect on-premises to cloud
Extend datacenter to cloud
Implement hybrid active-active setups
Meet compliance requirements
Migrate to cloud gradually

Connection Options

AWS Connectivity

1. Site-to-Site VPN

IPSec VPN over internet
Up to 1.25 Gbps per tunnel
Cost-effective for moderate bandwidth
Higher latency, internet-dependent

HCL

resource "aws_vpn_gateway" "main" {
  vpc_id = aws_vpc.main.id
  tags = {
    Name = "main-vpn-gateway"
  }
}

resource "aws_customer_gateway" "main" {
  bgp_asn    = 65000
  ip_address = "203.0.113.1"
  type       = "ipsec.1"
}

resource "aws_vpn_connection" "main" {
  vpn_gateway_id      = aws_vpn_gateway.main.id
  customer_gateway_id = aws_customer_gateway.main.id
  type                = "ipsec.1"
  static_routes_only  = false
}

2. AWS Direct Connect

Dedicated network connection
1 Gbps to 100 Gbps
Lower latency, consistent bandwidth
More expensive, setup time required

Reference: See references/direct-connect.md

Azure Connectivity

1. Site-to-Site VPN

HCL

resource "azurerm_virtual_network_gateway" "vpn" {
  name                = "vpn-gateway"
  location            = azurerm_resource_group.main.location
  resource_group_name = azurerm_resource_group.main.name

  type     = "Vpn"
  vpn_type = "RouteBased"
  sku      = "VpnGw1"

  ip_configuration {
    name                          = "vnetGatewayConfig"
    public_ip_address_id          = azurerm_public_ip.vpn.id
    private_ip_address_allocation = "Dynamic"
    subnet_id                     = azurerm_subnet.gateway.id
  }
}

2. Azure ExpressRoute

Private connection via connectivity provider
Up to 100 Gbps
Low latency, high reliability
Premium for global connectivity

GCP Connectivity

1. Cloud VPN

IPSec VPN (Classic or HA VPN)
HA VPN: 99.99% SLA
Up to 3 Gbps per tunnel

2. Cloud Interconnect

Dedicated (10 Gbps, 100 Gbps)
Partner (50 Mbps to 50 Gbps)
Lower latency than VPN

Hybrid Network Patterns

Pattern 1: Hub-and-Spoke

On-Premises Datacenter
         ↓
    VPN/Direct Connect
         ↓
    Transit Gateway (AWS) / vWAN (Azure)
         ↓
    ├─ Production VPC/VNet
    ├─ Staging VPC/VNet
    └─ Development VPC/VNet

Pattern 2: Multi-Region Hybrid

On-Premises
    ├─ Direct Connect → us-east-1
    └─ Direct Connect → us-west-2
            ↓
        Cross-Region Peering

Pattern 3: Multi-Cloud Hybrid

On-Premises Datacenter
    ├─ Direct Connect → AWS
    ├─ ExpressRoute → Azure
    └─ Interconnect → GCP

Routing Configuration

BGP Configuration

On-Premises Router:
- AS Number: 65000
- Advertise: 10.0.0.0/8

Cloud Router:
- AS Number: 64512 (AWS), 65515 (Azure)
- Advertise: Cloud VPC/VNet CIDRs

Route Propagation

Enable route propagation on route tables
Use BGP for dynamic routing
Implement route filtering
Monitor route advertisements

Security Best Practices

Use private connectivity (Direct Connect/ExpressRoute)
Implement encryption for VPN tunnels
Use VPC endpoints to avoid internet routing
Configure network ACLs and security groups
Enable VPC Flow Logs for monitoring
Implement DDoS protection
Use PrivateLink/Private Endpoints
Monitor connections with CloudWatch/Monitor
Implement redundancy (dual tunnels)
Regular security audits

High Availability

Dual VPN Tunnels

HCL

resource "aws_vpn_connection" "primary" {
  vpn_gateway_id      = aws_vpn_gateway.main.id
  customer_gateway_id = aws_customer_gateway.primary.id
  type                = "ipsec.1"
}

resource "aws_vpn_connection" "secondary" {
  vpn_gateway_id      = aws_vpn_gateway.main.id
  customer_gateway_id = aws_customer_gateway.secondary.id
  type                = "ipsec.1"
}

Active-Active Configuration

Multiple connections from different locations
BGP for automatic failover
Equal-cost multi-path (ECMP) routing
Monitor health of all connections

Monitoring and Troubleshooting

Key Metrics

Tunnel status (up/down)
Bytes in/out
Packet loss
Latency
BGP session status

Troubleshooting

BASH

# AWS VPN
aws ec2 describe-vpn-connections
aws ec2 get-vpn-connection-telemetry

# Azure VPN
az network vpn-connection show
az network vpn-connection show-device-config-script

Cost Optimization

Right-size connections based on traffic
Use VPN for low-bandwidth workloads
Consolidate traffic through fewer connections
Minimize data transfer costs
Use Direct Connect for high bandwidth
Implement caching to reduce traffic

Reference Files

references/vpn-setup.md - VPN configuration guide
references/direct-connect.md - Direct Connect setup

multi-cloud-architecture - For architecture decisions
terraform-module-library - For IaC implementation