creating-production-vpc-multi-az

Creating a Production-Ready VPC Across Multiple Availability Zones

Overview

Domain expertise for creating production-ready VPC infrastructure distributed across
multiple Availability Zones. Covers VPC creation with DNS support, public and private
subnet layout with automatic CIDR calculation, internet gateway, NAT gateways for
high-availability outbound access, route table configuration, and tiered security
groups following AWS Well-Architected principles.

Create a production VPC

To create a fully configured multi-AZ VPC with public/private subnets, NAT gateways,
route tables, and security groups, follow the procedure exactly.
See Production VPC creation procedure.

Key parameters:

• vpc_name (required): Name prefix for all resources
• region (required): Target AWS region
• allowed_web_cidrs (required): CIDR blocks allowed for web access — allow 0.0.0.0/0 only if explicitly requested
• vpc_cidr (optional, default 10.0.0.0/16): VPC CIDR block
• availability_zones (optional, default 3): Number of AZs (2–6)
• environment (required): Environment tag
• enable_ssh_access (optional, default false): Whether to create SSH security group

Troubleshooting

Insufficient Availability Zones

The target region must have at least 2 available AZs. Use aws ec2 describe-availability-zones to verify.

NAT Gateway creation delays

NAT Gateways can take several minutes to become available. The procedure waits for availability before configuring route tables.

Security group CIDR warnings

The procedure warns about 0.0.0.0/0 for web access CIDRs and recommends specific IP ranges for production workloads, but allows it if explicitly requested.