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:

• Load Balancer
• Load Balancer Listener
• Load Balancer Listener Certificate
• Load Balancer Listener default actions - All actions supported.
• Load Balancer Listener Rule
• Target Group

Not supported (yet):

• Target Group Attachment

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

• Complete Application Load Balancer
• Complete Network Load Balancer

Requirements

Name	Version
terraform	>= 0.12.6, < 0.14
aws	>= 2.54, < 4.0

Providers

Name	Version
aws	>= 2.54, < 4.0

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_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 - brandon@atscale.run. Many thanks to the contributors listed here!

License

Apache 2 Licensed. See LICENSE for full details.