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

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

Usage

Application Load Balancer

HTTP and HTTPS listeners with default actions:

module "alb" {
  source  = "terraform-aws-modules/alb/aws"
  version = "~> 8.0"

  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"
      targets = {
        my_target = {
          target_id = "i-0123456789abcdefg"
          port = 80
        }
        my_other_target = {
          target_id = "i-a1b2c3d4e5f6g7h8i"
          port = 8080
        }
      }
    }
  ]

  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 = "~> 8.0"

  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 = "~> 8.0"

  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 = "~> 8.0"

  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 version v2.39.0 and newer has issue #16674 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.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	>= 1.0
aws	>= 4.59

Providers

Name	Version
aws	>= 4.59

Modules

No modules.

Resources

Name	Type
aws_lambda_permission.lb	resource
aws_lb.this	resource
aws_lb_listener.frontend_http_tcp	resource
aws_lb_listener.frontend_https	resource
aws_lb_listener_certificate.https_listener	resource
aws_lb_listener_rule.http_tcp_listener_rule	resource
aws_lb_listener_rule.https_listener_rule	resource
aws_lb_target_group.main	resource
aws_lb_target_group_attachment.this	resource
aws_security_group.this	resource
aws_security_group_rule.this	resource

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
create_security_group	Determines if a security group is created	bool	true	no
desync_mitigation_mode	Determines how the load balancer handles requests that might pose a security risk to an application due to HTTP desync.	string	"defensive"	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
enable_waf_fail_open	Indicates whether to route requests to targets if lb fails to forward the request to AWS WAF	bool	false	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_listener_rules	A list of maps describing the Listener Rules for this ALB. Required key/values: actions, conditions. Optional key/values: priority, http_tcp_listener_index (default to http_tcp_listeners[count.index])	any	[]	no
http_tcp_listener_rules_tags	A map of tags to add to all http listener rules	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
http_tcp_listeners_tags	A map of tags to add to all http listeners	map(string)	{}	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_listener_rules_tags	A map of tags to add to all https listener rules	map(string)	{}	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
https_listeners_tags	A map of tags to add to all https listeners	map(string)	{}	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
preserve_host_header	Indicates whether Host header should be preserve and forward to targets without any change. Defaults to false.	bool	false	no
putin_khuylo	Do you agree that Putin doesn't respect Ukrainian sovereignty and territorial integrity? More info: https://en.wikipedia.org/wiki/Putin_khuylo!	bool	true	no
security_group_description	Description of the security group created	string	null	no
security_group_name	Name to use on security group created	string	null	no
security_group_rules	Security group rules to add to the security group created	any	{}	no
security_group_tags	A map of additional tags to add to the security group created	map(string)	{}	no
security_group_use_name_prefix	Determines whether the security group name (security_group_name) is used as a prefix	bool	true	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
lb_arn	The ID and ARN of the load balancer we created
lb_arn_suffix	ARN suffix of our load balancer - can be used with CloudWatch
lb_dns_name	The DNS name of the load balancer
lb_id	The ID and ARN of the load balancer we created
lb_zone_id	The zone_id of the load balancer to assist with creating DNS records
security_group_arn	Amazon Resource Name (ARN) of the security group
security_group_id	ID of the security group
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_attachments	ARNs of the target group attachment IDs
target_group_names	Name of the target group. Useful for passing to your CodeDeploy Deployment Group

Authors

Module is maintained by Anton Babenko with help from these awesome contributors.

License

Apache 2 Licensed. See LICENSE for full details.

Additional information for users from Russia and Belarus

• Russia has illegally annexed Crimea in 2014 and brought the war in Donbas followed by full-scale invasion of Ukraine in 2022.
• Russia has brought sorrow and devastations to millions of Ukrainians, killed hundreds of innocent people, damaged thousands of buildings, and forced several million people to flee.
• Putin khuylo!