Multi-AZ deployment for high availability in AWS - Mini Project: Build & Apply

Multi-AZ deployment for high availability

📋 What You'll Learn

💡 Why This Matters

🌍 Real World

Multi-AZ deployments are used to keep applications running even if one data center or Availability Zone has problems. This setup is common for websites and services that must stay online.

💼 Career

Cloud architects and DevOps engineers often design and implement Multi-AZ deployments to improve fault tolerance and availability of cloud applications.

1

Create the VPC and public subnets

Create a CloudFormation template that defines a VPC with CIDR block 10.0.0.0/16. Then create two public subnets named PublicSubnet1 and PublicSubnet2 with CIDR blocks 10.0.1.0/24 and 10.0.2.0/24 respectively. Assign AvailabilityZone properties as us-east-1a for PublicSubnet1 and us-east-1b for PublicSubnet2.

AWS

# Your CloudFormation YAML or JSON code here to create VPC and two public subnets

Need a hint?

Start by defining the VPC resource, then add two subnet resources with the specified CIDR blocks and availability zones.

2

Add Internet Gateway and route table

Add an Internet Gateway resource named InternetGateway and attach it to the VPC using VPCGatewayAttachment. Then create a route table named PublicRouteTable associated with the VPC. Add a route to 0.0.0.0/0 that points to the Internet Gateway. Finally, associate the route table with both PublicSubnet1 and PublicSubnet2 using SubnetRouteTableAssociation resources.

AWS

Resources:
  VPC:
    Type: AWS::EC2::VPC
    Properties:
      CidrBlock: 10.0.0.0/16
      EnableDnsSupport: true
      EnableDnsHostnames: true
  PublicSubnet1:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref VPC
      CidrBlock: 10.0.1.0/24
      AvailabilityZone: us-east-1a
      MapPublicIpOnLaunch: true
  PublicSubnet2:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref VPC
      CidrBlock: 10.0.2.0/24
      AvailabilityZone: us-east-1b
      MapPublicIpOnLaunch: true
# Add Internet Gateway, VPCGatewayAttachment, route table, route, and subnet route table associations below

Need a hint?

Attach the Internet Gateway to the VPC, create a route table with a default route to the Internet Gateway, and associate it with both public subnets.

3

Create Launch Configuration for EC2 instances

Add a LaunchConfiguration resource named WebServerLaunchConfig. Use the latest Amazon Linux 2 AMI by referencing AWS::SSM::Parameter::Value with parameter name /aws/service/ami-amazon-linux-latest/amzn2-ami-hvm-x86_64-gp2. Set the instance type to t3.micro and enable associate public IP address.

AWS

Resources:
  # Existing resources above
# Add LaunchConfiguration resource named WebServerLaunchConfig below

Need a hint?

Use a parameter to get the latest Amazon Linux 2 AMI ID from SSM Parameter Store. Set instance type and enable public IP association.

4

Create Auto Scaling Group with Multi-AZ deployment

Add an AutoScalingGroup resource named WebServerASG. Set the LaunchConfigurationName to WebServerLaunchConfig. Set MinSize, MaxSize, and DesiredCapacity all to 2. Set VPCZoneIdentifier to a list containing PublicSubnet1 and PublicSubnet2 to deploy instances across both Availability Zones.

AWS

Resources:
  # Existing resources above
# Add AutoScalingGroup resource named WebServerASG below

Need a hint?

Use the two public subnets in VPCZoneIdentifier to spread instances across AZs. Set min, max, and desired capacity to 2.