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:

terraform-terraform-label

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)
}

Requirements

Name	Version
terraform	>= 1.0
aws	>= 2.0

Providers

Name	Version
aws	>= 2.0

Modules

Name	Source	Version
label	cloudposse/label/null	0.25.0
security_group	cloudposse/security-group/aws	2.2.0
ssh_key_pair	cloudposse/key-pair/aws	0.19.0
this	cloudposse/label/null	0.25.0

Resources

Name	Type
aws_cloudwatch_metric_alarm.default	resource
aws_ebs_volume.default	resource
aws_eip.additional	resource
aws_eip.default	resource
aws_iam_instance_profile.default	resource
aws_iam_role.default	resource
aws_instance.default	resource
aws_network_interface.additional	resource
aws_network_interface_attachment.additional	resource
aws_volume_attachment.default	resource
aws_ami.info	data source
aws_caller_identity.default	data source
aws_iam_policy_document.default	data source
aws_region.default	data source

Inputs

Name	Description	Type	Default	Required
additional_ips_count	Count of additional EIPs	`number`	`0`	no
additional_tag_map	Additional key-value pairs to add to each map in `tags_as_list_of_maps`. Not added to `tags` or `id`. This is for some rare cases where resources want additional configuration of tags and therefore take a list of maps with tag key, value, and additional configuration.	`map(string)`	`{}`	no
ami	The AMI to use for the instance	`string`	n/a	yes
ami_owner	Owner of the given AMI	`string`	n/a	yes
applying_period	The period in seconds over which the specified statistic is applied	`number`	`60`	no
assign_eip_address	Assign an Elastic IP address to the instance	`bool`	`true`	no
associate_public_ip_address	Associate a public IP address with the instance	`bool`	`false`	no
attributes	ID element. Additional attributes (e.g. `workers` or `cluster`) to add to `id`, in the order they appear in the list. New attributes are appended to the end of the list. The elements of the list are joined by the `delimiter` and treated as a single ID element.	`list(string)`	`[]`	no
availability_zone	Availability Zone the instance is launched in. If not set, will be launched in the first AZ of the region	`string`	`""`	no
comparison_operator	The arithmetic operation to use when comparing the specified Statistic and Threshold. Possible values are: GreaterThanOrEqualToThreshold, GreaterThanThreshold, LessThanThreshold, LessThanOrEqualToThreshold	`string`	`"GreaterThanOrEqualToThreshold"`	no
context	Single object for setting entire context at once. See description of individual variables for details. Leave string and numeric variables as `null` to use default value. Individual variable settings (non-null) override settings in context object, except for attributes, tags, and additional_tag_map, which are merged.	`any`	`{ "additional_tag_map": {}, "attributes": [], "delimiter": null, "descriptor_formats": {}, "enabled": true, "environment": null, "id_length_limit": null, "label_key_case": null, "label_order": [], "label_value_case": null, "labels_as_tags": [ "unset" ], "name": null, "namespace": null, "regex_replace_chars": null, "stage": null, "tags": {}, "tenant": null }`	no
default_alarm_action	Default alarm action	`string`	`"action/actions/AWS_EC2.InstanceId.Reboot/1.0"`	no
delete_on_termination	Whether the volume should be destroyed on instance termination	`bool`	`true`	no
delimiter	Delimiter to be used between ID elements. Defaults to `-` (hyphen). Set to `""` to use no delimiter at all.	`string`	`null`	no
descriptor_formats	Describe additional descriptors to be output in the `descriptors` output map. Map of maps. Keys are names of descriptors. Values are maps of the form `{<br/> format = string<br/> labels = list(string)<br/>}` (Type is `any` so the map values can later be enhanced to provide additional options.) `format` is a Terraform format string to be passed to the `format()` function. `labels` is a list of labels, in order, to pass to `format()` function. Label values will be normalized before being passed to `format()` so they will be identical to how they appear in `id`. Default is `{}` (`descriptors` output will be empty).	`any`	`{}`	no
disable_api_termination	Enable EC2 Instance Termination Protection	`bool`	`false`	no
ebs_device_names	Name of the EBS device to mount	`list(string)`	`[ "/dev/xvdb", "/dev/xvdc", "/dev/xvdd", "/dev/xvde", "/dev/xvdf", "/dev/xvdg", "/dev/xvdh", "/dev/xvdi", "/dev/xvdj", "/dev/xvdk", "/dev/xvdl", "/dev/xvdm", "/dev/xvdn", "/dev/xvdo", "/dev/xvdp", "/dev/xvdq", "/dev/xvdr", "/dev/xvds", "/dev/xvdt", "/dev/xvdu", "/dev/xvdv", "/dev/xvdw", "/dev/xvdx", "/dev/xvdy", "/dev/xvdz" ]`	no
ebs_iops	Amount of provisioned IOPS. This must be set with a volume_type of io1	`number`	`0`	no
ebs_optimized	Launched EC2 instance will be EBS-optimized	`bool`	`false`	no
ebs_volume_count	Count of EBS volumes that will be attached to the instance	`number`	`0`	no
ebs_volume_encrypted	Size of the EBS volume in gigabytes	`bool`	`true`	no
ebs_volume_size	Size of the EBS volume in gigabytes	`number`	`10`	no
ebs_volume_type	The type of EBS volume. Can be standard, gp2 or io1	`string`	`"gp2"`	no
enabled	Set to false to prevent the module from creating any resources	`bool`	`null`	no
environment	ID element. Usually used for region e.g. 'uw2', 'us-west-2', OR role 'prod', 'staging', 'dev', 'UAT'	`string`	`null`	no
evaluation_periods	The number of periods over which data is compared to the specified threshold	`number`	`5`	no
generate_ssh_key_pair	If true, create a new key pair and save the pem for it to the current working directory	`bool`	`false`	no
id_length_limit	Limit `id` to this many characters (minimum 6). Set to `0` for unlimited length. Set to `null` for keep the existing setting, which defaults to `0`. Does not affect `id_full`.	`number`	`null`	no
instance_count	Count of ec2 instances to create	`number`	`1`	no
instance_type	The type of the instance	`string`	`"t2.micro"`	no
ipv6_address_count	Number of IPv6 addresses to associate with the primary network interface. Amazon EC2 chooses the IPv6 addresses from the range of your subnet	`number`	`0`	no
ipv6_addresses	List of IPv6 addresses from the range of the subnet to associate with the primary network interface	`list(string)`	`[]`	no
kms_key_id	KMS key ID used to encrypt EBS volume. When specifying kms_key_id, ebs_volume_encrypted needs to be set to true	`string`	`null`	no
label_key_case	Controls the letter case of the `tags` keys (label names) for tags generated by this module. Does not affect keys of tags passed in via the `tags` input. Possible values: `lower`, `title`, `upper`. Default value: `title`.	`string`	`null`	no
label_order	The order in which the labels (ID elements) appear in the `id`. Defaults to ["namespace", "environment", "stage", "name", "attributes"]. You can omit any of the 6 labels ("tenant" is the 6th), but at least one must be present.	`list(string)`	`null`	no
label_value_case	Controls the letter case of ID elements (labels) as included in `id`, set as tag values, and output by this module individually. Does not affect values of tags passed in via the `tags` input. Possible values: `lower`, `title`, `upper` and `none` (no transformation). Set this to `title` and set `delimiter` to `""` to yield Pascal Case IDs. Default value: `lower`.	`string`	`null`	no
labels_as_tags	Set of labels (ID elements) to include as tags in the `tags` output. Default is to include all labels. Tags with empty values will not be included in the `tags` output. Set to `[]` to suppress all generated tags. Notes: The value of the `name` tag, if included, will be the `id`, not the `name`. Unlike other `null-label` inputs, the initial setting of `labels_as_tags` cannot be changed in later chained modules. Attempts to change it will be silently ignored.	`set(string)`	`[ "default" ]`	no
metadata_http_endpoint_enabled	Whether the metadata service is available	`bool`	`true`	no
metadata_http_tokens_required	Whether or not the metadata service requires session tokens, also referred to as Instance Metadata Service Version 2.	`bool`	`true`	no
metric_name	The name for the alarm's associated metric. Allowed values can be found in https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/ec2-metricscollected.html	`string`	`"StatusCheckFailed_Instance"`	no
metric_namespace	The namespace for the alarm's associated metric. Allowed values can be found in https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/aws-namespaces.html	`string`	`"AWS/EC2"`	no
metric_threshold	The value against which the specified statistic is compared	`number`	`1`	no
monitoring	Launched EC2 instance will have detailed monitoring enabled	`bool`	`true`	no
name	ID element. Usually the component or solution name, e.g. 'app' or 'jenkins'. This is the only ID element not also included as a `tag`. The "name" tag is set to the full `id` string. There is no tag with the value of the `name` input.	`string`	`null`	no
namespace	ID element. Usually an abbreviation of your organization name, e.g. 'eg' or 'cp', to help ensure generated IDs are globally unique	`string`	`null`	no
permissions_boundary_arn	Policy ARN to attach to instance role as a permissions boundary	`string`	`""`	no
private_ips	Private IP address to associate with the instances in the VPC	`list(string)`	`[]`	no
regex_replace_chars	Terraform regular expression (regex) string. Characters matching the regex will be removed from the ID elements. If not set, `"/[^a-zA-Z0-9-]/"` is used to remove all characters other than hyphens, letters and digits.	`string`	`null`	no
region	AWS Region the instance is launched in	`string`	n/a	yes
root_block_device_encrypted	Whether to encrypt the root block device	`bool`	`true`	no
root_iops	Amount of provisioned IOPS. This must be set if root_volume_type is set to `io1`	`number`	`0`	no
root_volume_size	Size of the root volume in gigabytes	`number`	`10`	no
root_volume_type	Type of root volume. Can be standard, gp2 or io1	`string`	`"gp2"`	no
security_group_description	The Security Group description.	`string`	`"EC2 instances Security Group"`	no
security_group_enabled	Whether to create default Security Group for EC2 instances.	`bool`	`true`	no
security_group_name	The name to assign to the security group. Must be unique within the VPC. If not provided, will be derived from the `null-label.context` passed in. If `create_before_destroy` is true, will be used as a name prefix.	`list(string)`	`[]`	no
security_group_rules	A list of maps of Security Group rules. The values of map is fully complated with `aws_security_group_rule` resource. To get more info see https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/security_group_rule .	`list(any)`	`[]`	no
security_groups	A list of Security Group IDs to associate with EC2 instances.	`list(string)`	`[]`	no
source_dest_check	Controls if traffic is routed to the instance when the destination address does not match the instance. Used for NAT or VPNs	`bool`	`true`	no
ssh_key_pair	SSH key pair to be provisioned on the instance	`string`	`""`	no
ssh_key_pair_path	Path to where the generated key pairs will be created. Defaults to $${path.cwd}	`string`	`""`	no
stage	ID element. Usually used to indicate role, e.g. 'prod', 'staging', 'source', 'build', 'test', 'deploy', 'release'	`string`	`null`	no
statistic_level	The statistic to apply to the alarm's associated metric. Allowed values are: SampleCount, Average, Sum, Minimum, Maximum	`string`	`"Maximum"`	no
subnet	VPC Subnet ID the instance is launched in	`string`	n/a	yes
tags	Additional tags (e.g. `{'BusinessUnit': 'XYZ'}`). Neither the tag keys nor the tag values will be modified by this module.	`map(string)`	`{}`	no
tenant	ID element _(Rarely used, not included by default)_. A customer identifier, indicating who this instance of a resource is for	`string`	`null`	no
user_data	Instance user data. Do not pass gzip-compressed data via this argument	`string`	`""`	no
vpc_id	The ID of the VPC that the instance security group belongs to	`string`	n/a	yes

Outputs

Name	Description
alarm_ids	CloudWatch Alarm IDs
aws_key_pair_name	Name of AWS key pair
ebs_ids	IDs of EBSs
eip_per_instance_count	Number of EIPs per instance.
eni_to_eip_map	Map of ENI with EIP
ids	Disambiguated IDs list
instance_count	Total number of instances created
name	Instance(s) name
new_ssh_keypair_generated	Was a new ssh_key_pair generated
primary_network_interface_ids	IDs of the instance's primary network interface
private_dns	Private DNS records of instances
private_ips	Private IPs of instances
public_dns	All public DNS records for the public interfaces and ENIs
public_ips	List of Public IPs of instances (or EIP)
role_names	Names of AWS IAM Roles associated with creating instance
security_group_arn	EC2 instances Security Group ARN
security_group_id	EC2 instances Security Group ID
security_group_ids	ID on the new AWS Security Group associated with creating instance
security_group_name	EC2 instances Security Group name
ssh_key_pem_path	Path where SSH key pair was created (if applicable)

Module: ec2-instance-group

Usage​

Simple example:​

Example with additional volumes and EIP​

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

Requirements​

Providers​

Modules​

Resources​

Inputs​

Outputs​