lab02-alb

Lab 02: Application Load Balancer

Goal

Create an Application Load Balancer.

Instructions

Make sure you are starting from the starting point for Lab 02.

cp lab02-alb/starting-point/template.yaml template.yaml

Extend the CloudFormation template (template.yaml) with the following resources.

ALB's Security Group

Create a security group that allows TCP traffic on port 80 from anywhere (0.0.0.0/0).

Application Load Balancer

Create an ALB with the following characteristics:

• Idle timeout: 60 seconds
• Accessible from the Internet (internet-facing)
• Attach the security group from above
• Assign all public subnets from the VPC

ALB Listener

Create an ALB Listener that listens on port 80 using the HTTP protocol. Define a default action that returns a fixed response in the form of a HTTP Status Code 404.

Finally, create or update your own ECS stack. Replace $user with your name (e.g. andreas).

aws cloudformation create-stack --stack-name ecs-$user --template-body file://template.yaml --parameters ParameterKey=ParentVPCStack,ParameterValue=vpc-$user
aws cloudformation update-stack --stack-name ecs-$user --template-body file://template.yaml --parameters ParameterKey=ParentVPCStack,ParameterValue=vpc-$user

Wait until the stack reaches the status UPDATE_COMPLETE. Afterwards, use the following command to obtain the URL of your load balancer. Replace $user with your name (e.g. andreas).

aws cloudformation describe-stacks --stack-name ecs-$user --query 'Stacks[0].Outputs[?OutputKey==`URL`].OutputValue' --output text

Open the URL in your browser. You should see a 404 error.

Help

• CloudFormation Resource AWS::EC2::SecurityGroup
• CloudFormation Resource AWS::ElasticLoadBalancingV2::LoadBalancer
• CloudFormation Resource AWS::ElasticLoadBalancingV2::Listener
• CloudFormation Function Fn::Split

The following snippet shows an example of how to import the public subnets of the VPC from your vpc-$user stack.

LoadBalancer:
    Type: 'AWS::ElasticLoadBalancingV2::LoadBalancer'
    Properties:
      Subnets: !Split [',', {'Fn::ImportValue': !Sub '${ParentVPCStack}-SubnetsPublic'}]