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Module: ec2-instance-group

Terraform Module for providing N general purpose EC2 hosts.

If you only need to provision a single EC2 instance, consider using the terraform-aws-ec2-instance module instead.

IMPORTANT This module by-design does not provision an AutoScaling group. It was designed to provision a discrete number of instances suitable for running stateful services such as databases (e.g. Kafka, Redis, etc).

Included features:

  • Automatically create a Security Group
  • Option to switch EIP attachment
  • CloudWatch monitoring and automatic reboot if instance hangs
  • Assume Role capability

Usage​

Note: add ${var.ssh_key_pair} private key to the ssh agent.

Include this repository as a module in your existing terraform code.

Simple example:​

module "instance" {
  source = "cloudposse/ec2-instance-group/aws"
  # Cloud Posse recommends pinning every module to a specific version
  # version = "x.x.x"
  namespace                   = "eg"
  stage                       = "prod"
  name                        = "app"
  ami                         = "ami-a4dc46db"
  ami_owner                   = "099720109477"
  ssh_key_pair                = var.ssh_key_pair
  instance_type               = var.instance_type
  vpc_id                      = var.vpc_id
  security_groups             = var.security_groups
  subnet                      = var.subnet
  instance_count              = 3
}

Example with additional volumes and EIP​

module "kafka_instance" {
  source = "cloudposse/ec2-instance-group/aws"
  # Cloud Posse recommends pinning every module to a specific version
  # version = "x.x.x"

  namespace                   = "eg"
  stage                       = "prod"
  name                        = "app"
  ami                         = "ami-a4dc46db"
  ami_owner                   = "099720109477"
  ssh_key_pair                = var.ssh_key_pair
  vpc_id                      = var.vpc_id
  security_groups             = var.security_groups
  subnet                      = var.subnet
  associate_public_ip_address = true
  additional_ips_count        = 1
  ebs_volume_count            = 2
  instance_count              = 3

  security_group_rules = [
    {
      type        = "egress"
      from_port   = 0
      to_port     = 65535
      protocol    = "-1"
      cidr_blocks = ["0.0.0.0/0"]
    },
    {
      type        = "ingress"
      from_port   = 22
      to_port     = 22
      protocol    = "tcp"
      cidr_blocks = ["0.0.0.0/0"]
    },
    {
      type        = "ingress"
      from_port   = 80
      to_port     = 80
      protocol    = "tcp"
      cidr_blocks = ["0.0.0.0/0"]
    },
    {
      type        = "ingress"
      from_port   = 443
      to_port     = 443
      protocol    = "tcp"
      cidr_blocks = ["0.0.0.0/0"]
    }
  ]
}

Additional complete working example with variations of how to use the module​

In /examples directory

This module depends on these modules:

It is necessary to run terraform get or terraform init to download this module.

Now reference the label when creating an instance (for example):

resource "aws_ami_from_instance" "example" {
  count              = length(module.instance.*.id)
  name               = "app"
  source_instance_id = element(module.instance.*.id, count.index)
}