gerardodavidlopezcastillo / TF_ALB-HTTPHeaderQueryStringRedirects_Public

Create AWS Application Load Balancer Custom HTTP Header, 302 Redirects with Query String and Host Headers

description
Create AWS Application Load Balancer Custom HTTP Header, 302 Redirects with Query String and Host Headers

AWS ALB Query String, Host Header Redirects and Custom Header Routing

Pre-requisites

• You need a Registered Domain in AWS Route53 to implement this usecase
• Copy your terraform-key.pem file to terraform-manifests/private-key folder

Step-01: Introduction

• We are going to implement four AWS ALB Application HTTPS Listener Rules

• Rule-1 and Rule-2 will outline the Custom HTTP Header based Routing

• Rule-3 and Rule-4 will outline the HTTP Redirect using Query String and Host Header based rules

• Rule-1: custom-header=my-app-1 should go to App1 EC2 Instances

• Rule-2: custom-header=my-app-2 should go to App2 EC2 Instances

• Rule-3: When Query-String, website=aws-eks redirect to https://www.linkedin.com/in/gdlopezcastillo/

• Rule-4: When Host Header = azure-aks.devopsincloud.com, redirect to https://linktr.ee/gdlopezcastillo.

• Understand about Priority feature for Rules priority = 2

Step-02: c10-02-ALB-application-loadbalancer.tf

• Define different HTTPS Listener Rules for ALB Load Balancer

Step-02-01: Rule-1: Custom Header Rule for App-1

• Rule-1: custom-header=my-app-1 should go to App1 EC2 Instances

        # Rule-1: myapp1-rule - custom-header=my-app-1 should go to App1 EC2 Instances
        myapp1-rule = {
          priority = 1
          actions = [{
            type = "weighted-forward"
            target_groups = [
              {
                target_group_key = "mytg1"
                weight           = 1
              }
            ]
            stickiness = {
              enabled  = true
              duration = 3600
            }
          }]
          conditions = [{
            http_header = {
              http_header_name = "custom-header"
              values           = ["app-1", "app1", "my-app-1"]
            }
          }]
        }# End of myapp1-rule

Step-02-02: Rule-2: Custom Header Rule for App-1

• Rule-2: custom-header=my-app-2 should go to App2 EC2 Instances

        # Rule-2: myapp2-rule - custom-header=my-app-2 should go to App2 EC2 Instances    
        myapp2-rule = {
          priority = 2
          actions = [{
            type = "weighted-forward"
            target_groups = [
              {
                target_group_key = "mytg2"
                weight           = 1
              }
            ]
            stickiness = {
              enabled  = true
              duration = 3600
            }
          }]
          conditions = [{
            http_header = {
              http_header_name = "custom-header"
              values           =  ["app-2", "app2", "my-app-2"]
            }
          }]
        }# End of myapp2-rule Block
  

Step-02-03: Rule-3: Query String Redirect

• Rule-3: When Query-String, website=aws-eks redirect to https://www.linkedin.com/in/gdlopezcastillo/

  # Rule-3: When Query-String, website=aws-eks redirect to https://www.linkedin.com/in/gdlopezcastillo/
        # Rule-3: Query String Redirect Redirect Rule
        my-redirect-query = {
          priority = 3
          actions = [{
            type        = "redirect"
            status_code = "HTTP_302"
            host        = "stacksimplify.com"
            path        = "/aws-eks/"
            query       = ""
            protocol    = "HTTPS"
          }]

          conditions = [{
            query_string = {
              key   = "website"
              value = "aws-eks"
            }
          }]
        }# End of Rule-3 Query String Redirect Redirect Rule

Step-02-04: Rule-4: Host Header Redirect

• Rule-4: When Host Header = azure-aks.devopsincloud.com, redirect to https://linktr.ee/gdlopezcastillo

  # Rule-4: When Host Header = azure-aks.devopsincloud.com, redirect to https://linktr.ee/gdlopezcastillo
        # Rule-4: Host Header Redirect
        my-redirect-hh = {
          priority = 4
          actions = [{
            type        = "redirect"
            status_code = "HTTP_302"
            host        = "stacksimplify.com"
            path        = "/azure-aks/azure-kubernetes-service-introduction/"
            query       = ""
            protocol    = "HTTPS"
          }]

          conditions = [{
            host_header = {
              values = ["azure-aks11.devopsincloud.com"]
            }
          }]
        }# Rule-4: Host Header Redirect 

Step-03: c12-route53-dnsregistration.tf

# DNS Registration 
## Default DNS
resource "aws_route53_record" "default_dns" {
  zone_id = data.aws_route53_zone.mydomain.zone_id 
  name    = "myapps11.devopsincloud.com"
  type    = "A"
  alias {
    name                   = module.alb.dns_name
    zone_id                = module.alb.zone_id
    evaluate_target_health = true
  }  
}

## Testing Host Header - Redirect to External Site from ALB HTTPS Listener Rules
resource "aws_route53_record" "app1_dns" {
  zone_id = data.aws_route53_zone.mydomain.zone_id 
  name    = "azure-aks11.devopsincloud.com"
  type    = "A"
  alias {
    name                   = module.alb.dns_name
    zone_id                = module.alb.zone_id
    evaluate_target_health = true
  }  
}

Step-04: Execute Terraform Commands

# Terraform Initialize
terraform init

# Terraform Validate
terraform validate

# Terraform Plan
terraform plan

# Terrform Apply
terraform apply -auto-approve

Step-06: Verify HTTP Header Based Routing (Rule-1 and Rule-2)

• Rest Clinets we can use
• https://restninja.io/
• https://www.webtools.services/online-rest-api-client
• https://reqbin.com/

# Verify Rule-1 and Rule-2
https://myapps.devopsincloud.com
custom-header = my-app-1  - Should get the page from App1 
custom-header = my-app-2  - Should get the page from App2

Step-07: Verify Rule-3

• When Query-String, website=aws-eks redirect to https://www.linkedin.com/in/gdlopezcastillo/

# Verify Rule-3
https://myapps.devopsincloud.com/?website=aws-eks 
Observation: 
1. Should Redirect to https://www.linkedin.com/in/gdlopezcastillo/

Step-08: Verify Rule-4

• When Host Header = azure-aks.devopsincloud.com, redirect to https://linktr.ee/gdlopezcastillo

# Verify Rule-4
http://azure-aks.devopsincloud.com
Observation: 
1. Should redirect to https://linktr.ee/gdlopezcastillo

Step-09: Clean-Up

# Destroy Resources
terraform destroy -auto-approve

# Delete Files
rm -rf .terraform*
rm -rf terraform.tfstate

References

• Terraform AWS ALB