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Hybrid_cloud

Hybrid cloud combines on-premises infrastructure with public cloud services, allowing organizations to leverage existing investments while taking advantage of cloud scalability. This chapter covers hybrid cloud architectures, connectivity options, AWS/Azure/GCP implementations, DNS integration, and best practices for designing and managing hybrid environments.


┌─────────────────────────────────────────────────────────────────────────┐
│ CLOUD CONNECTIVITY OPTIONS │
├─────────────────────────────────────────────────────────────────────────┤
│ │
│ ┌─────────────────────────────────────────────────────────────────┐ │
│ │ VPN (IPSec) │ │
│ │ ┌─────────────────────────────────────────────────────────┐ │ │
│ │ │ • Quick deployment (hours) │ │ │
│ │ │ • Runs over public internet │ │ │
│ │ │ • Bandwidth: Up to 1.25 Gbps │ │ │
│ │ │ • Encryption: IPSec │ │ │
│ │ │ • Latency: Variable (internet-dependent) │ │ │
│ │ │ • Cost: Hourly + data transfer │ │ │
│ │ │ • Best for: Dev/test, low-traffic connections │ │ │
│ │ └─────────────────────────────────────────────────────────┘ │ │
│ │ │ │
│ │ Direct Connect │ │
│ │ ┌─────────────────────────────────────────────────────────┐ │ │
│ │ │ • Dedicated connection (1G/10G/100G) │ │ │
│ │ │ • AWS locations, colocation partners │ │ │
│ │ │ • Bandwidth: Up to 100Gbps │ │ │
│ │ │ • Latency: Consistent, ~1-2ms │ │ │
│ │ │ • Cost: Monthly port fee + data transfer │ │ │
│ │ │ • Best for: Production, high-volume workloads │ │ │
│ │ └─────────────────────────────────────────────────────────┘ │ │
│ │ │ │
│ │ Transit Gateway │ │
│ │ ┌─────────────────────────────────────────────────────────┐ │ │
│ │ │ • Central hub for VPC and VPN connections │ │ │
│ │ │ • Scalable, regional │ │ │
│ │ │ • Supports routing between VPCs │ │ │
│ │ │ • Simplifies network architecture │ │ │
│ │ │ • Best for: Multiple VPCs, hub-and-spoke │ │ │
│ │ └─────────────────────────────────────────────────────────┘ │ │
│ │ │ │
│ └─────────────────────────────────────────────────────────────────┘ │
│ │
└─────────────────────────────────────────────────────────────────────────┘
┌─────────────────────────────────────────────────────────────────────────┐
│ HYBRID CLOUD PATTERNS │
├─────────────────────────────────────────────────────────────────────────┤
│ │
│ Classic Hybrid: │
│ ┌─────────────┐ ┌─────────────┐ │
│ │ On-Prem │◄──────►│ Cloud │ │
│ │ Data Center│ VPN │ VPC │ │
│ └─────────────┘ └─────────────┘ │
│ │
│ Extended VPC: │
│ ┌─────────────┐ ┌─────────────┐ │
│ │ On-Prem │◄──────►│ Cloud │ │
│ │ DB Server │ Direct │ App Tier │ │
│ └─────────────┘ Connect └─────────────┘ │
│ │
│ Multi-Cloud + On-Prem: │
│ ┌─────────────┐ ┌─────────────┐ ┌─────────────┐ │
│ │ On-Prem │◄──────►│ AWS │◄──────►│ Azure │ │
│ └─────────────┘ └─────────────┘ └─────────────┘ │
│ │
└─────────────────────────────────────────────────────────────────────────┘

Terminal window
# ============================================================
# AWS SITE-TO-SITE VPN CONFIGURATION
# ============================================================
# 1. Create Customer Gateway
aws ec2 create-customer-gateway \
--bgp-asn 65000 \
--ip-address 203.0.113.1 \
--type ipsec.1
# 2. Create VPN Gateway
aws ec2 create-vpn-gateway --type ipsec.1
# 3. Attach to VPC
aws ec2 attach-vpn-gateway \
--vpn-gateway-id vgw-12345678 \
--vpc-id vpc-12345678
# 4. Create Site-to-Site VPN Connection
aws ec2 create-vpn-connection \
--customer-gateway-id cgw-12345678 \
--vpn-gateway-id vgw-12345678 \
--type ipsec.1 \
--static-routes-only
# 5. Download Configuration
aws ec2 describe-vpn-connections \
--vpn-connection-ids vpn-12345678
# 6. Configure Routes
# On customer gateway, configure:
# - IKE version: v1
# - Encryption: aes-128
# - Hash: sha1
# - DH group: 2
# - Lifetime: 28800 seconds
# 7. Configure BGP (if using dynamic routing)
aws ec2 create-vpn-connection \
--customer-gateway-id cgw-12345678 \
--vpn-gateway-id vgw-12345678 \
--type ipsec.1 \
--options "TunnelOptions=[{TunnelInsideCidr=169.254.0.0/30}]"
Terminal window
# ============================================================
# AWS TRANSIT GATEWAY
# ============================================================
# Create Transit Gateway
aws ec2 create-transit-gateway \
--description "Hybrid Cloud TGW" \
--amazon-asn 64512 \
--options "AutoAcceptSharedAttachments=enable,DefaultRouteTableAssociation=enable,DefaultRouteTablePropagation=enable"
# Attach VPC
aws ec2 create-transit-gateway-vpc-attachment \
--transit-gateway-id tgw-12345678 \
--vpc-id vpc-12345678 \
--subnet-ids subnet-12345678 subnet-23456789
# Attach VPN
aws ec2 create-transit-gateway-attachment \
--transit-gateway-id tgw-12345678 \
--vpn-attachment \
--customer-gateway-id cgw-12345678 \
--vpn-connection-id vpn-12345678
# Create Route Table
aws ec2 create-transit-gateway-route-table \
--transit-gateway-id tgw-12345678
# Add Route
aws ec2 create-transit-gateway-route \
--transit-gateway-route-table-id tgw-rtb-12345678 \
--destination-cidr-block 10.0.0.0/16 \
--transit-gateway-attachment-id tgw-attach-12345678

┌─────────────────────────────────────────────────────────────────────────┐
│ AWS DIRECT CONNECT WORKFLOW │
├─────────────────────────────────────────────────────────────────────────┤
│ │
│ ┌─────────────────────────────────────────────────────────────────┐ │
│ │ Step 1: Request Connection │ │
│ │ • Choose location (AWS Direct Connect location) │ │
│ │ • Select port speed (1G, 10G, 100G) │ │
│ │ • Choose partner or dedicated │ │
│ └─────────────────────────────────────────────────────────────────┘ │
│ │ │
│ ▼ │
│ ┌─────────────────────────────────────────────────────────────────┐ │
│ │ Step 2: Create Virtual Interface │ │
│ │ • Private VIF: Connect to VPC │ │
│ │ • Public VIF: Connect to AWS services (S3, etc.) │ │
│ │ • Transit VIF: Connect to Transit Gateway │ │
│ └─────────────────────────────────────────────────────────────────┘ │
│ │ │
│ ▼ │
│ ┌─────────────────────────────────────────────────────────────────┐ │
│ │ Step 3: Configure Router │ │
│ │ • BGP peering (ASN, IP addresses) │ │
│ │ • BGP authentication │ │
│ │ • Advertise prefixes │ │
│ └─────────────────────────────────────────────────────────────────┘ │
│ │ │
│ ▼ │
│ ┌─────────────────────────────────────────────────────────────────┐ │
│ │ Step 4: Verify Connection │ │
│ │ • AWS console shows "Available" │ │
│ │ • Test connectivity │ │
│ │ • Confirm BGP is up │ │
│ └─────────────────────────────────────────────────────────────────┘ │
│ │
└─────────────────────────────────────────────────────────────────────────┘
Terminal window
# ============================================================
# DIRECT CONNECT CONFIGURATION
# ============================================================
# Create Private VIF
aws directconnect create-private-virtual-interface \
--connection-id dxcon-fh1xoj2p \
--owner-account 123456789012 \
--new-private-virtual-interface virtualInterfaceName="Private" \
vlan=100 \
asn=65001 \
amazon-address=169.254.0.1/30 \
customer-address=169.254.0.2/30 \
--bgp-peers=""
# Create Public VIF
aws directconnect create-public-virtual-interface \
--connection-id dxcon-fh1xoj2p \
--owner-account 123456789012 \
--new-public-virtual-interface virtualInterfaceName="Public" \
vlan=200 \
asn=65001 \
amazon-address=169.254.1.1/30 \
customer-address=169.254.1.2/30 \
--bgp-peers=""
# Router Configuration (Cisco)
interface TenGigabitEthernet0/0
description AWS Direct Connect
no switchport
ip address 169.254.0.2 255.255.255.252
!
router bgp 65001
neighbor 169.254.0.1 remote-as 7224
neighbor 169.254.0.1 description AWS Direct Connect
network 10.0.0.0 mask 255.255.0.0

Terminal window
# ============================================================
# HYBRID DNS CONFIGURATION
# ============================================================
# AWS Route 53 Inbound Resolver
# - Forwards on-prem queries to Route 53
# - Resolves cloud-hosted DNS zones
# 1. Create Inbound Endpoint
aws route53 create-resolver-endpoint \
--name "Hybrid-Inbound" \
--direction INBOUND \
--security-group-ids sg-12345678 \
--ip-addresses SubnetId=subnet-12345678,Ip=10.0.1.10 \
SubnetId=subnet-23456789,Ip=10.0.2.10
# 2. Create Outbound Endpoint
aws route53 create-resolver-endpoint \
--name "Hybrid-Outbound" \
--direction OUTBOUND \
--security-group-ids sg-12345678 \
--ip-addresses SubnetId=subnet-12345678,Ip=10.0.1.20
# 3. Create Forwarding Rules
aws route53 create-resolver-rule \
--name "OnPrem-Forward" \
--rule-type FORWARD \
--domain-name "internal.company.com" \
--target-ips "Ip=10.0.0.2,Port=53" \
--resolver-endpoint-id rslvr-in-12345678
# VPC DNS Settings
# Enable DNS hostnames and support
aws ec2 modify-vpc-attribute \
--vpc-id vpc-12345678 \
--enable-dns-hostnames "{\"Value\":true}"
aws ec2 modify-vpc-attribute \
--vpc-id vpc-12345678 \
--enable-dns-support "{\"Value\":true}"

┌─────────────────────────────────────────────────────────────────────────┐
│ HYBRID CLOUD INTERVIEW QUESTIONS │
├─────────────────────────────────────────────────────────────────────────┤
Q1: What are the benefits of hybrid cloud? │
A1: │
- Leverage existing on-premises investments │
- Scalability for burst workloads │
- Data sovereignty (keep sensitive data on-prem) │
- Regulatory compliance │
- Disaster recovery capabilities │
- Gradual migration to cloud │
─────────────────────────────────────────────────────────────────────────┤
Q2: Compare VPN vs Direct Connect. │
A2: │
VPN: Quick setup, lower cost, internet-dependent, lower bandwidth │
Direct Connect: Dedicated, higher bandwidth, consistent latency, │
higher cost, requires physical connection │
─────────────────────────────────────────────────────────────────────────┤
Q3: How do you connect on-premises DNS to cloud? │
A3: │
- Route 53 Resolver endpoints │
- Conditional forwarders for internal domains │
- Inbound endpoint: on-prem queries resolve cloud domains │
- Outbound endpoint: cloud queries forward to on-prem DNS │
- VPC DNS settings must be enabled │
─────────────────────────────────────────────────────────────────────────┤
Q4: What is Transit Gateway and when would you use it? │
A4: │
- Central hub for connecting VPCs and VPN connections │
- Simplifies network architecture │
- Scalable: supports thousands of attachments │
- Use for: multiple VPCs, hub-and-spoke topology, │
connecting to on-premises │
─────────────────────────────────────────────────────────────────────────┤
Q5: How do you secure hybrid cloud connectivity? │
A5: │
- Use IPSec VPN with strong encryption │
- Implement network ACLs and security groups │
- Enable VPC Flow Logs │
- Use private subnets for sensitive workloads │
- Implement proper IAM roles and policies │
- Enable CloudTrail for audit logging │
─────────────────────────────────────────────────────────────────────────┤
Q6: What are the challenges of hybrid cloud? │
A6: │
- Network latency between cloud and on-prem │
- Data transfer costs │
- Complex networking configuration │
- Security and compliance management │
- Data synchronization challenges │
- Skill requirements for both environments │
─────────────────────────────────────────────────────────────────────────┤
Q7: How does BGP work with Direct Connect? │
A7: │
- BGP (Border Gateway Protocol) establishes peering relationship │
- AWS side uses ASN 7224 (public) or 7224 (private) │
- Customer advertises on-premises prefixes │
- AWS advertises VPC prefixes │
- Provides dynamic routing with automatic failover │
─────────────────────────────────────────────────────────────────────────┤
Q8: What is a Virtual Interface in Direct Connect? │
A8: │
- Private VIF: Connects to VPC, for private IP communication │
- Public VIF: Connects to AWS public services (S3, DynamoDB, etc.) │
- Transit VIF: Connects to Transit Gateway │
─────────────────────────────────────────────────────────────────────────┤
Q9: How do you troubleshoot hybrid connectivity issues? │
A9: │
- Check VPN status: AWS console, customer gateway │
- Verify BGP status and prefixes advertised │
- Check routing tables and security groups │
- Test DNS resolution both directions │
- Verify IPsec tunnel status │
- Check network ACLs and firewall rules │
─────────────────────────────────────────────────────────────────────────┤
Q10: When would you use AWS Outposts? │
A10: │
- Run AWS services on-premises │
- Low-latency requirements │
- Data residency needs │
- Same API/management as AWS cloud │
- Ideal for edge locations, factories, remote sites │
└─────────────────────────────────────────────────────────────────────────┘

Terminal window
# VPN
aws ec2 create-vpn-connection --customer-gateway-id X --vpn-gateway-id Y
# Direct Connect
aws directconnect create-private-virtual-interface
# Transit Gateway
aws ec2 create-transit-gateway
# DNS
aws route53 create-resolver-endpoint --direction INBOUND

  • VPN: Quick setup, lower bandwidth, over internet
  • Direct Connect: Dedicated, high bandwidth, consistent latency
  • Transit Gateway: Central hub for multiple VPCs/VPNs
  • DNS: Route 53 Resolver for hybrid resolution

Chapter 95: Cloud Monitoring


Last Updated: February 2026