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Terraform module to create an AWS Application/Network Load Balancer (ALB/NLB) and associated resources

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AWS Application and Network Load Balancer (ALB & NLB) Terraform module

Terraform module which creates Application and Network Load Balancer resources on AWS.

These types of resources are supported:

Not supported (yet):

Terraform versions

Terraform 0.12 and newer. Pin module version to ~> v5.0. Submit pull-requests to master branch.

Terraform 0.11. Pin module version to ~> v3.0. Submit pull-requests to terraform011 branch.

Usage

Application Load Balancer

HTTP and HTTPS listeners with default actions:

module "alb" {
  source  = "terraform-aws-modules/alb/aws"
  version = "~> 5.0"
  
  name = "my-alb"

  load_balancer_type = "application"

  vpc_id             = "vpc-abcde012"
  subnets            = ["subnet-abcde012", "subnet-bcde012a"]
  security_groups    = ["sg-edcd9784", "sg-edcd9785"]
  
  access_logs = {
    bucket = "my-alb-logs"
  }

  target_groups = [
    {
      name_prefix      = "pref-"
      backend_protocol = "HTTP"
      backend_port     = 80
      target_type      = "instance"
    }
  ]

  https_listeners = [
    {
      port               = 443
      protocol           = "HTTPS"
      certificate_arn    = "arn:aws:iam::123456789012:server-certificate/test_cert-123456789012"
      target_group_index = 0
    }
  ]

  http_tcp_listeners = [
    {
      port               = 80
      protocol           = "HTTP"
      target_group_index = 0
    }
  ]

  tags = {
    Environment = "Test"
  }
}

HTTP to HTTPS redirect and HTTPS cognito authentication:

module "alb" {
  source  = "terraform-aws-modules/alb/aws"
  version = "~> 5.0"
  
  name = "my-alb"

  load_balancer_type = "application"

  vpc_id             = "vpc-abcde012"
  subnets            = ["subnet-abcde012", "subnet-bcde012a"]
  security_groups    = ["sg-edcd9784", "sg-edcd9785"]
  
  access_logs = {
    bucket = "my-alb-logs"
  }

  target_groups = [
    {
      name_prefix      = "pref-"
      backend_protocol = "HTTPS"
      backend_port     = 443
      target_type      = "instance"
    }
  ]

  https_listeners = [
    {
      port                 = 443
      protocol             = "HTTPS"
      certificate_arn      = "arn:aws:iam::123456789012:server-certificate/test_cert-123456789012"
      action_type          = "authenticate-cognito"
      target_group_index   = 0
      authenticate_cognito = {
        user_pool_arn       = "arn:aws:cognito-idp::123456789012:userpool/test-pool"
        user_pool_client_id = "6oRmFiS0JHk="
        user_pool_domain    = "test-domain-com"
      }
    }
  ]

  http_tcp_listeners = [
    {
      port        = 80
      protocol    = "HTTP"
      action_type = "redirect"
      redirect = {
        port        = "443"
        protocol    = "HTTPS"
        status_code = "HTTP_301"
      }
    }
  ]

  tags = {
    Environment = "Test"
  }
}

Cognito Authentication only on certain routes, with redirects for other routes:

module "alb" {
  source  = "terraform-aws-modules/alb/aws"
  version = "~> 5.0"
  
  name = "my-alb"

  load_balancer_type = "application"

  vpc_id             = "vpc-abcde012"
  subnets            = ["subnet-abcde012", "subnet-bcde012a"]
  security_groups    = ["sg-edcd9784", "sg-edcd9785"]
  
  access_logs = {
    bucket = "my-alb-logs"
  }

  target_groups = [
    {
      name_prefix      = "default"
      backend_protocol = "HTTPS"
      backend_port     = 443
      target_type      = "instance"
    }
  ]

  https_listeners = [
    {
      port                 = 443
      certificate_arn      = "arn:aws:iam::123456789012:server-certificate/test_cert-123456789012"
    }
  ]

  https_listener_rules = [
    {
      https_listener_index = 0
      priority             = 5000

      actions = [{
        type        = "redirect"
        status_code = "HTTP_302"
        host        = "www.youtube.com"
        path        = "/watch"
        query       = "v=dQw4w9WgXcQ"
        protocol    = "HTTPS"
      }]

      conditions = [{
        path_patterns = ["/onboarding", "/docs"]
      }]
    },
    {
      https_listener_index = 0
      priority             = 2

      actions = [
        {
          type = "authenticate-cognito"

          user_pool_arn       = "arn:aws:cognito-idp::123456789012:userpool/test-pool"
          user_pool_client_id = "6oRmFiS0JHk="
          user_pool_domain    = "test-domain-com"
        },
        {
          type               = "forward"
          target_group_index = 0
        }
      ]

      conditions = [{
        path_patterns = ["/protected-route", "private/*"]
      }]
    }
  ]
}

When you're using ALB Listener rules, make sure that every rule's actions block ends in a forward, redirect, or fixed-response action so that every rule will resolve to some sort of an HTTP response. Checkout the AWS documentation for more information.

Network Load Balancer (TCP_UDP, UDP, TCP and TLS listeners)

module "nlb" {
  source  = "terraform-aws-modules/alb/aws"
  version = "~> 5.0"
  
  name = "my-nlb"

  load_balancer_type = "network"

  vpc_id  = "vpc-abcde012"
  subnets = ["subnet-abcde012", "subnet-bcde012a"]
  
  access_logs = {
    bucket = "my-nlb-logs"
  }

  target_groups = [
    {
      name_prefix      = "pref-"
      backend_protocol = "TCP"
      backend_port     = 80
      target_type      = "ip"
    }
  ]

  https_listeners = [
    {
      port               = 443
      protocol           = "TLS"
      certificate_arn    = "arn:aws:iam::123456789012:server-certificate/test_cert-123456789012"
      target_group_index = 0
    }
  ]

  http_tcp_listeners = [
    {
      port               = 80
      protocol           = "TCP"
      target_group_index = 0
    }
  ]

  tags = {
    Environment = "Test"
  }
}

Assumptions

It's recommended you use this module with terraform-aws-vpc, terraform-aws-security-group, and terraform-aws-autoscaling.

Notes

  1. Terraform AWS provider v2.39.0 (via Terraform 0.12) has issue #7987 related to "Provider produced inconsistent final plan". It means that S3 bucket has to be created before referencing it as an argument inside access_logs = { bucket = "my-already-created-bucket-for-logs" }, so this won't work: access_logs = { bucket = module.log_bucket.this_s3_bucket_id }.

Conditional creation

Sometimes you need to have a way to create ALB resources conditionally but Terraform does not allow to use count inside module block, so the solution is to specify argument create_lb.

# This LB will not be created
module "lb" {
 source = "terraform-aws-modules/alb/aws"

 create_lb = false
 # ... omitted
}

Examples

Requirements

Name Version
terraform >= 0.12.6
aws >= 2.54

Providers

Name Version
aws >= 2.54

Inputs

Name Description Type Default Required
access_logs Map containing access logging configuration for load balancer. map(string) {} no
create_lb Controls if the Load Balancer should be created bool true no
drop_invalid_header_fields Indicates whether invalid header fields are dropped in application load balancers. Defaults to false. bool false no
enable_cross_zone_load_balancing Indicates whether cross zone load balancing should be enabled in application load balancers. bool false no
enable_deletion_protection If true, deletion of the load balancer will be disabled via the AWS API. This will prevent Terraform from deleting the load balancer. Defaults to false. bool false no
enable_http2 Indicates whether HTTP/2 is enabled in application load balancers. bool true no
extra_ssl_certs A list of maps describing any extra SSL certificates to apply to the HTTPS listeners. Required key/values: certificate_arn, https_listener_index (the index of the listener within https_listeners which the cert applies toward). list(map(string)) [] no
http_tcp_listeners A list of maps describing the HTTP listeners or TCP ports for this ALB. Required key/values: port, protocol. Optional key/values: target_group_index (defaults to http_tcp_listeners[count.index]) any [] no
https_listener_rules A list of maps describing the Listener Rules for this ALB. Required key/values: actions, conditions. Optional key/values: priority, https_listener_index (default to https_listeners[count.index]) any [] no
https_listeners A list of maps describing the HTTPS listeners for this ALB. Required key/values: port, certificate_arn. Optional key/values: ssl_policy (defaults to ELBSecurityPolicy-2016-08), target_group_index (defaults to https_listeners[count.index]) any [] no
idle_timeout The time in seconds that the connection is allowed to be idle. number 60 no
internal Boolean determining if the load balancer is internal or externally facing. bool false no
ip_address_type The type of IP addresses used by the subnets for your load balancer. The possible values are ipv4 and dualstack. string "ipv4" no
lb_tags A map of tags to add to load balancer map(string) {} no
listener_ssl_policy_default The security policy if using HTTPS externally on the load balancer. See. string "ELBSecurityPolicy-2016-08" no
load_balancer_create_timeout Timeout value when creating the ALB. string "10m" no
load_balancer_delete_timeout Timeout value when deleting the ALB. string "10m" no
load_balancer_type The type of load balancer to create. Possible values are application or network. string "application" no
load_balancer_update_timeout Timeout value when updating the ALB. string "10m" no
name The resource name and Name tag of the load balancer. string null no
name_prefix The resource name prefix and Name tag of the load balancer. Cannot be longer than 6 characters string null no
security_groups The security groups to attach to the load balancer. e.g. ["sg-edcd9784","sg-edcd9785"] list(string) [] no
subnet_mapping A list of subnet mapping blocks describing subnets to attach to network load balancer list(map(string)) [] no
subnets A list of subnets to associate with the load balancer. e.g. ['subnet-1a2b3c4d','subnet-1a2b3c4e','subnet-1a2b3c4f'] list(string) null no
tags A map of tags to add to all resources map(string) {} no
target_group_tags A map of tags to add to all target groups map(string) {} no
target_groups A list of maps containing key/value pairs that define the target groups to be created. Order of these maps is important and the index of these are to be referenced in listener definitions. Required key/values: name, backend_protocol, backend_port any [] no
vpc_id VPC id where the load balancer and other resources will be deployed. string null no

Outputs

Name Description
http_tcp_listener_arns The ARN of the TCP and HTTP load balancer listeners created.
http_tcp_listener_ids The IDs of the TCP and HTTP load balancer listeners created.
https_listener_arns The ARNs of the HTTPS load balancer listeners created.
https_listener_ids The IDs of the load balancer listeners created.
target_group_arn_suffixes ARN suffixes of our target groups - can be used with CloudWatch.
target_group_arns ARNs of the target groups. Useful for passing to your Auto Scaling group.
target_group_names Name of the target group. Useful for passing to your CodeDeploy Deployment Group.
this_lb_arn The ID and ARN of the load balancer we created.
this_lb_arn_suffix ARN suffix of our load balancer - can be used with CloudWatch.
this_lb_dns_name The DNS name of the load balancer.
this_lb_id The ID and ARN of the load balancer we created.
this_lb_zone_id The zone_id of the load balancer to assist with creating DNS records.

Authors

Module managed by Anton Babenko. Originally created and maintained by Brandon O'Connor - [email protected]. Many thanks to the contributors listed here!

License

Apache 2 Licensed. See LICENSE for full details.

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Terraform module to create an AWS Application/Network Load Balancer (ALB/NLB) and associated resources

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