How to create Resource: aws_lb (Load Balancer)

Application Load Balancer

resource "aws_lb" "test" {
  name               = "test-lb-tf"
  internal           = false
  load_balancer_type = "application"
  security_groups    = [aws_security_group.lb_sg.id]
  subnets            = [for subnet in aws_subnet.public : subnet.id]
  enable_deletion_protection = true
  access_logs {
    bucket  = aws_s3_bucket.lb_logs.bucket
    prefix  = "test-lb"
    enabled = true
  }
  tags = {
    Environment = "production"
  }
}

Network Load Balancer

resource "aws_lb" "test" {
  name               = "test-lb-tf"
  internal           = false
  load_balancer_type = "network"
  subnets            = [for subnet in aws_subnet.public : subnet.id]
  enable_deletion_protection = true
  tags = {
    Environment = "production"
  }
}

Specifying Elastic IPs

resource "aws_lb" "example" {
  name               = "example"
  load_balancer_type = "network"
  subnet_mapping {
    subnet_id     = aws_subnet.example1.id
    allocation_id = aws_eip.example1.id
  }
  subnet_mapping {
    subnet_id     = aws_subnet.example2.id
    allocation_id = aws_eip.example2.id
  }
}

Specifying private IP addresses for an internal-facing load balancer

resource "aws_lb" "example" {
  name               = "example"
  load_balancer_type = "network"
  subnet_mapping {
    subnet_id            = aws_subnet.example1.id
    private_ipv4_address = "10.0.1.15"
  }
  subnet_mapping {
    subnet_id            = aws_subnet.example2.id
    private_ipv4_address = "10.0.2.15"
  }
}

Argument Reference

NOTE:

Please note that internal LBs can only use ipv4 as the ip_address_type. You can only change to dualstack ip_address_type if the selected subnets are IPv6 enabled.

NOTE:

Please note that one of either subnets or subnet_mapping is required.

The following arguments are supported:

• name - (Optional) The name of the LB. This name must be unique within your AWS account, can have a maximum of 32 characters, must contain only alphanumeric characters or hyphens, and must not begin or end with a hyphen. If not specified, Terraform will autogenerate a name beginning with tf-lb.
• name_prefix - (Optional) Creates a unique name beginning with the specified prefix. Conflicts with name.
• internal - (Optional) If true, the LB will be internal.
• load_balancer_type - (Optional) The type of load balancer to create. Possible values are application, gateway, or network. The default value is application.
• security_groups - (Optional) A list of security group IDs to assign to the LB. Only valid for Load Balancers of type application.
• drop_invalid_header_fields - (Optional) Indicates whether HTTP headers with header fields that are not valid are removed by the load balancer (true) or routed to targets (false). The default is false. Elastic Load Balancing requires that message header names contain only alphanumeric characters and hyphens. Only valid for Load Balancers of type application.
• access_logs - (Optional) An Access Logs block. Access Logs documented below.
• subnets - (Optional) A list of subnet IDs to attach to the LB. Subnets cannot be updated for Load Balancers of type network. Changing this value for load balancers of type network will force a recreation of the resource.
• subnet_mapping - (Optional) A subnet mapping block as documented below.
• idle_timeout - (Optional) The time in seconds that the connection is allowed to be idle. Only valid for Load Balancers of type application. Default: 60.
• enable_deletion_protection - (Optional) 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.
• enable_cross_zone_load_balancing - (Optional) If true, cross-zone load balancing of the load balancer will be enabled. This is a network load balancer feature. Defaults to false.
• enable_http2 - (Optional) Indicates whether HTTP/2 is enabled in application load balancers. Defaults to true.
• enable_waf_fail_open - (Optional) Indicates whether to allow a WAF-enabled load balancer to route requests to targets if it is unable to forward the request to AWS WAF. Defaults to false.
• customer_owned_ipv4_pool - (Optional) The ID of the customer owned ipv4 pool to use for this load balancer.
• ip_address_type - (Optional) The type of IP addresses used by the subnets for your load balancer. The possible values are ipv4 and dualstack
• desync_mitigation_mode - (Optional) Determines how the load balancer handles requests that might pose a security risk to an application due to HTTP desync. Valid values are monitor, defensive (default), strictest.
• tags - (Optional) A map of tags to assign to the resource. If configured with a provider default_tags configuration block present, tags with matching keys will overwrite those defined at the provider-level.

Access Logs (access_logs) support the following:

• bucket - (Required) The S3 bucket name to store the logs in.
• prefix - (Optional) The S3 bucket prefix. Logs are stored in the root if not configured.
• enabled - (Optional) Boolean to enable / disable access_logs. Defaults to false, even when bucket is specified.

Subnet Mapping (subnet_mapping) blocks support the following:

• subnet_id - (Required) The id of the subnet of which to attach to the load balancer. You can specify only one subnet per Availability Zone.
• allocation_id - (Optional) The allocation ID of the Elastic IP address.
• private_ipv4_address - (Optional) A private ipv4 address within the subnet to assign to the internal-facing load balancer.
• ipv6_address - (Optional) An ipv6 address within the subnet to assign to the internet-facing load balancer.

Attributes Reference

In addition to all arguments above, the following attributes are exported:

• id - The ARN of the load balancer (matches arn).
• arn - The ARN of the load balancer (matches id).
• arn_suffix - The ARN suffix for use with CloudWatch Metrics.
• dns_name - The DNS name of the load balancer.
• tags_all - A map of tags assigned to the resource, including those inherited from the provider default_tags configuration block.
• zone_id - The canonical hosted zone ID of the load balancer (to be used in a Route 53 Alias record).
• subnet_mapping.*.outpost_id - ID of the Outpost containing the load balancer.

Timeouts

aws_lb provides the following Timeouts configuration options:

• create - (Default 10 minutes) Used for Creating LB
• update - (Default 10 minutes) Used for LB modifications
• delete - (Default 10 minutes) Used for destroying LB

Import

LBs can be imported using their ARN, e.g.,

$ terraform import aws_lb.bar arn:aws:elasticloadbalancing:us-west-2:123456789012:loadbalancer/app/my-load-balancer/50dc6c495c0c9188