Cloud Networking Fundamentals: VPCs, Subnets, and Routing | DevOpsNess

Cloud Networking Fundamentals: VPCs, Subnets, and Routing

Understanding AWS networking is essential. This guide covers VPCs, subnets, and routing.

VPC Configuration #

yaml.yaml

Resources:
  VPC:
    Type: AWS::EC2::VPC
    Properties:
      CidrBlock: 10.0.0.0/16
      EnableDnsHostnames: true
      EnableDnsSupport: true

Subnets #

yaml.yaml

Resources:
  PublicSubnet:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref VPC
      CidrBlock: 10.0.1.0/24
      AvailabilityZone: us-east-1a
  
  PrivateSubnet:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref VPC
      CidrBlock: 10.0.2.0/24
      AvailabilityZone: us-east-1b

Internet Gateway #

yaml.yaml

Resources:
  InternetGateway:
    Type: AWS::EC2::InternetGateway
  
  GatewayAttachment:
    Type: AWS::EC2::VPCGatewayAttachment
    Properties:
      VpcId: !Ref VPC
      InternetGatewayId: !Ref InternetGateway

Route Tables #

yaml.yaml

Resources:
  PublicRouteTable:
    Type: AWS::EC2::RouteTable
    Properties:
      VpcId: !Ref VPC
      Routes:
      - DestinationCidrBlock: 0.0.0.0/0
        GatewayId: !Ref InternetGateway

Best Practices #

Use multiple availability zones
Separate public and private subnets
Use NAT gateways for private subnet internet access
Implement security groups
Use VPC endpoints for AWS services

Conclusion #

Design VPCs with multiple subnets, proper routing, and security groups for secure and scalable architectures.

For Cloud Networking Fundamentals: VPCs, Subnets, and Routing, define pre-deploy checks, rollout gates, and rollback triggers before release. Track p95 latency, error rate, and cost per request for at least 24 hours after deployment. If the trend regresses from baseline, revert quickly and document the decision in the runbook.

Keep the operating model simple under pressure: one owner per change, one decision channel, and clear stop conditions. Review alert quality regularly to remove noise and ensure on-call engineers can distinguish urgent failures from routine variance.

Repeatability is the goal. Convert successful interventions into standard operating procedures and version them in the repository so future responders can execute the same flow without ambiguity.