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tf_aws_alb

A Terraform module containing common configurations for an AWS Application Load Balancer (ALB) running over HTTP/HTTPS.

Assumptions

  • You want to associate the ASG with a target group and ALB
  • You've created a Virtual Private Cloud (VPC) + subnets where you intend to put this ALB and backing instances.
  • You can fully bootstrap your instances using an AMI + user_data.
  • You want to configure a listener for HTTPS
  • You've uploaded an SSL certificate to AWS/IAM

The module supports both (mutually exclusive):

  • Internal IP ALBs
  • External IP ALBs

It's recommended you use this module with sg_https_only and tf_aws_asg_elb

Why ALB instad of ELB?

Admittedly, the use-case appears almost identical to how one would use an ELB BUT we inherit a few bonuses by moving to ALB. Those are best outlined in AWS's documentation. For an example of using ALB with ECS look no further than the hashicorp example.

Input Variables

  • alb_is_internal - Determines if the ALB is externally facing or internal. (Optional; default: false)
  • alb_name - Name of the ALB as it appears in the AWS console. (Optional; default: my-alb)
  • alb_protocols - A comma delimited list of protocols the ALB will accept for incoming connections. Only HTTP and HTTPS are supported. (Optional; default: HTTPS)
  • alb_security_groups - A comma delimited list of security groups to attach to the ALB. (Required)
  • aws_region - Region to deploy our resources. (Required)
  • aws_account_id - The AWS account ID. (Required)
  • backend_port - Port on which the backing instances serve traffic. (Optional; default: 80)
  • backend_protocol - Protocol the backing instances use. (Optional; default: HTTP)
  • certificate_arn - . (Required if using HTTPS in alb_protocols)
  • cookie_duration - If sticky sessions via cookies are desired, set this variable to a value from 2 - 604800 seconds. (Optional)
  • health_check_path - Path for the load balancer to health check instances. (Optional; default: /)
  • log_bucket - S3 bucket where access logs should land. (Required)
  • log_prefix - S3 prefix within the log_bucket where logs should land. (Optional)
  • principle_account_id - A mapping of regions to principle account IDs used to send LB logs. (Should only change as regions are added)
  • subnets - ALB will be created in the subnets in this list. (Required)
  • vpc_id - Resources will be created in the VPC with this id. (Required)
  • tags - A mapping of tags to assign to the resource.

Outputs

  • alb_id - id of the ALB created.
  • alb_dns_name - DNS CNAME of the ALB created.
  • alb_zone_id - Route53 zone_id of the newly minted ALB.
  • target_group_arn - arn of the target group. Useful for passing to your Auto Scaling group module.
  • principle_account_id - the id of the AWS root user within this region. See docs here.

Usage example:

A full example leveraging other community modules is contained in the test/fixtures directory. Here's the gist if you're using this module without:

  1. Set the input variables from above in variables.tf.
  2. Define the ALB module using the following in your main.tf:
module "alb" {
  source              = "github.com/terraform-community-modules/tf_aws_alb//alb"
  alb_security_groups = "${var.alb_security_groups}"
  aws_account_id      = "${var.aws_account_id}"
  certificate_arn     = "${var.certificate_arn}"
  log_bucket          = "${var.log_bucket}"
  log_prefix          = "${var.log_prefix}"
  subnets             = "${var.public_subnets}"
  vpc_id              = "${var.vpc_id}"

  tags {
      "Terraform" = "true"
      "Env" = "${terraform.env}"
  }
}
  1. Always terraform plan to see your change before running terraform apply.
  2. Win the day!

Testing

This module has been packaged with awspec tests through test kitchen. To run them:

  1. Install the prerequisites of rvm and ruby 2.4.0 via homebrew.
  2. Install bundler and the gems from our Gemfile:
gem install bundler; bundle install
  1. Configure variables in test/fixtures/terraform.tfvars. An example of how this should look is in terraform.tfvars.example.
  2. Test using kitchen test from the root of the repo.

Contributing

Report issues/questions/feature requests on in the Issues section.

Pull requests are welcome! Ideally create a feature branch and issue for every individual change you make. These are the steps:

  1. Fork the repo.
  2. Create your feature branch from master (git checkout -b my-new-feature).
  3. Commit your awesome changes (git commit -am 'Added some feature').
  4. Push to the branch (git push origin my-new-feature).
  5. Create a new Pull Request and tell us about your changes.

Change log

The Change log captures all important release notes.

Authors

Created and maintained by Brandon O'Connor - [email protected].

License

MIT Licensed. See LICENSE for full details.