BREAKING CHANGE: update module to include latest features and remove use of...

BREAKING CHANGE: update module to include latest features and remove use of `count` for module `count`/`for_each` (#234)

.github/workflows/pre-commit.yml

@@ -91,7 +91,7 @@ jobs:
       - name: Install pre-commit dependencies
         run: |
           pip install pre-commit
-          curl -Lo ./terraform-docs.tar.gz https://github.com/terraform-docs/terraform-docs/releases/download/v0.13.0/terraform-docs-v0.13.0-$(uname)-amd64.tar.gz && tar -xzf terraform-docs.tar.gz && chmod +x terraform-docs && sudo mv terraform-docs /usr/bin/
+          curl -Lo ./terraform-docs.tar.gz https://github.com/terraform-docs/terraform-docs/releases/download/v0.13.0/terraform-docs-v0.13.0-$(uname)-amd64.tar.gz && tar -xzf terraform-docs.tar.gz terraform-docs && chmod +x terraform-docs && sudo mv terraform-docs /usr/bin/
           curl -L "$(curl -s https://api.github.com/repos/terraform-linters/tflint/releases/latest | grep -o -E "https://.+?_linux_amd64.zip")" > tflint.zip && unzip tflint.zip && rm tflint.zip && sudo mv tflint /usr/bin/
       - name: Execute pre-commit
         # Run all pre-commit checks on max version supported

.pre-commit-config.yaml

@@ -21,6 +21,6 @@ repos:
           - '--args=--only=terraform_standard_module_structure'
           - '--args=--only=terraform_workspace_remote'
   - repo: git://github.com/pre-commit/pre-commit-hooks
-    rev: v3.4.0
+    rev: v4.0.1
     hooks:
       - id: check-merge-conflict

README.md

 # AWS EC2 Instance Terraform module
 
-Terraform module which creates EC2 instance(s) on AWS.
+Terraform module which creates an EC2 instance on AWS.
 
 ## Usage
 
+### Single EC2 Instance
+
 ```hcl
-module "ec2_cluster" {
+module "ec2_instance" {
   source  = "terraform-aws-modules/ec2-instance/aws"
-  version                = "~> 2.0"
+  version = "~> 3.0"
+
+  name = "single-instance"
+
+  ami                    = "ami-ebd02392"
+  instance_type          = "t2.micro"
+  key_name               = "user1"
+  monitoring             = true
+  vpc_security_group_ids = ["sg-12345678"]
+  subnet_id              = "subnet-eddcdzz4"
+
+  tags = {
+    Terraform   = "true"
+    Environment = "dev"
+  }
+}
+```
+
+### Multiple EC2 Instance
+
+```hcl
+module "ec2_instance" {
+  source  = "terraform-aws-modules/ec2-instance/aws"
+  version = "~> 3.0"
+
+  for_each = toset(["one", "two", "three"])
 
-  name                   = "my-cluster"
-  instance_count         = 5
+  name = "instance-${each.key}"
 
   ami                    = "ami-ebd02392"
   instance_type          = "t2.micro"
@@ -28,7 +54,7 @@ module "ec2_cluster" {
 
 ## Examples
 
-- [Basic EC2 instance](https://github.com/terraform-aws-modules/terraform-aws-ec2-instance/tree/master/examples/basic)
+- [Complete EC2 instance](https://github.com/terraform-aws-modules/terraform-aws-ec2-instance/tree/master/examples/complete)
 - [EC2 instance with EBS volume attachment](https://github.com/terraform-aws-modules/terraform-aws-ec2-instance/tree/master/examples/volume-attachment)
 
 ## Make an encrypted AMI for use
@@ -75,23 +101,22 @@ data "aws_ami" "ubuntu-xenial" {
 
 ## Notes
 
-- `network_interface` can't be specified together with `vpc_security_group_ids`, `associate_public_ip_address`, `subnet_id`. See [basic example](https://github.com/terraform-aws-modules/terraform-aws-ec2-instance/tree/master/examples/basic) for details.
+- `network_interface` can't be specified together with `vpc_security_group_ids`, `associate_public_ip_address`, `subnet_id`. See [complete example](https://github.com/terraform-aws-modules/terraform-aws-ec2-instance/tree/master/examples/complete) for details.
 - Changes in `ebs_block_device` argument will be ignored. Use [aws_volume_attachment](https://www.terraform.io/docs/providers/aws/r/volume_attachment.html) resource to attach and detach volumes from AWS EC2 instances. See [this example](https://github.com/terraform-aws-modules/terraform-aws-ec2-instance/tree/master/examples/volume-attachment).
-- One of `subnet_id` or `subnet_ids` is required. If both are provided, the value of `subnet_id` is prepended to the value of `subnet_ids`.
 
 <!-- BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK -->
 ## Requirements
 
 | Name | Version |
 |------|---------|
-| <a name="requirement_terraform"></a> [terraform](#requirement\_terraform) | >= 0.12.6 |
-| <a name="requirement_aws"></a> [aws](#requirement\_aws) | >= 3.24 |
+| <a name="requirement_terraform"></a> [terraform](#requirement\_terraform) | >= 0.13.1 |
+| <a name="requirement_aws"></a> [aws](#requirement\_aws) | >= 3.51 |
 
 ## Providers
 
 | Name | Version |
 |------|---------|
-| <a name="provider_aws"></a> [aws](#provider\_aws) | >= 3.24 |
+| <a name="provider_aws"></a> [aws](#provider\_aws) | >= 3.51 |
 
 ## Modules
 
@@ -107,39 +132,43 @@ No modules.
 
 | Name | Description | Type | Default | Required |
 |------|-------------|------|---------|:--------:|
-| <a name="input_ami"></a> [ami](#input\_ami) | ID of AMI to use for the instance | `string` | n/a | yes |
-| <a name="input_associate_public_ip_address"></a> [associate\_public\_ip\_address](#input\_associate\_public\_ip\_address) | If true, the EC2 instance will have associated public IP address | `bool` | `null` | no |
+| <a name="input_ami"></a> [ami](#input\_ami) | ID of AMI to use for the instance | `string` | `""` | no |
+| <a name="input_associate_public_ip_address"></a> [associate\_public\_ip\_address](#input\_associate\_public\_ip\_address) | Whether to associate a public IP address with an instance in a VPC | `bool` | `null` | no |
+| <a name="input_availability_zone"></a> [availability\_zone](#input\_availability\_zone) | AZ to start the instance in | `string` | `null` | no |
+| <a name="input_capacity_reservation_specification"></a> [capacity\_reservation\_specification](#input\_capacity\_reservation\_specification) | Describes an instance's Capacity Reservation targeting option | `any` | `null` | no |
 | <a name="input_cpu_core_count"></a> [cpu\_core\_count](#input\_cpu\_core\_count) | Sets the number of CPU cores for an instance. | `number` | `null` | no |
-| <a name="input_cpu_credits"></a> [cpu\_credits](#input\_cpu\_credits) | The credit option for CPU usage (unlimited or standard) | `string` | `"standard"` | no |
+| <a name="input_cpu_credits"></a> [cpu\_credits](#input\_cpu\_credits) | The credit option for CPU usage (unlimited or standard) | `string` | `null` | no |
 | <a name="input_cpu_threads_per_core"></a> [cpu\_threads\_per\_core](#input\_cpu\_threads\_per\_core) | Sets the number of CPU threads per core for an instance (has no effect unless cpu\_core\_count is also set). | `number` | `null` | no |
-| <a name="input_disable_api_termination"></a> [disable\_api\_termination](#input\_disable\_api\_termination) | If true, enables EC2 Instance Termination Protection | `bool` | `false` | no |
+| <a name="input_create"></a> [create](#input\_create) | Whether to create an instance | `bool` | `true` | no |
+| <a name="input_disable_api_termination"></a> [disable\_api\_termination](#input\_disable\_api\_termination) | If true, enables EC2 Instance Termination Protection | `bool` | `null` | no |
 | <a name="input_ebs_block_device"></a> [ebs\_block\_device](#input\_ebs\_block\_device) | Additional EBS block devices to attach to the instance | `list(map(string))` | `[]` | no |
-| <a name="input_ebs_optimized"></a> [ebs\_optimized](#input\_ebs\_optimized) | If true, the launched EC2 instance will be EBS-optimized | `bool` | `false` | no |
+| <a name="input_ebs_optimized"></a> [ebs\_optimized](#input\_ebs\_optimized) | If true, the launched EC2 instance will be EBS-optimized | `bool` | `null` | no |
 | <a name="input_enable_volume_tags"></a> [enable\_volume\_tags](#input\_enable\_volume\_tags) | Whether to enable volume tags (if enabled it conflicts with root\_block\_device tags) | `bool` | `true` | no |
+| <a name="input_enclave_options_enabled"></a> [enclave\_options\_enabled](#input\_enclave\_options\_enabled) | Whether Nitro Enclaves will be enabled on the instance. Defaults to `false` | `bool` | `null` | no |
 | <a name="input_ephemeral_block_device"></a> [ephemeral\_block\_device](#input\_ephemeral\_block\_device) | Customize Ephemeral (also known as Instance Store) volumes on the instance | `list(map(string))` | `[]` | no |
-| <a name="input_get_password_data"></a> [get\_password\_data](#input\_get\_password\_data) | If true, wait for password data to become available and retrieve it. | `bool` | `false` | no |
-| <a name="input_iam_instance_profile"></a> [iam\_instance\_profile](#input\_iam\_instance\_profile) | The IAM Instance Profile to launch the instance with. Specified as the name of the Instance Profile. | `string` | `""` | no |
-| <a name="input_instance_count"></a> [instance\_count](#input\_instance\_count) | Number of instances to launch | `number` | `1` | no |
-| <a name="input_instance_initiated_shutdown_behavior"></a> [instance\_initiated\_shutdown\_behavior](#input\_instance\_initiated\_shutdown\_behavior) | Shutdown behavior for the instance | `string` | `""` | no |
-| <a name="input_instance_type"></a> [instance\_type](#input\_instance\_type) | The type of instance to start | `string` | n/a | yes |
-| <a name="input_ipv6_address_count"></a> [ipv6\_address\_count](#input\_ipv6\_address\_count) | A number of IPv6 addresses to associate with the primary network interface. Amazon EC2 chooses the IPv6 addresses from the range of your subnet. | `number` | `null` | no |
+| <a name="input_get_password_data"></a> [get\_password\_data](#input\_get\_password\_data) | If true, wait for password data to become available and retrieve it. | `bool` | `null` | no |
+| <a name="input_hibernation"></a> [hibernation](#input\_hibernation) | If true, the launched EC2 instance will support hibernation | `bool` | `null` | no |
+| <a name="input_host_id"></a> [host\_id](#input\_host\_id) | ID of a dedicated host that the instance will be assigned to. Use when an instance is to be launched on a specific dedicated host | `string` | `null` | no |
+| <a name="input_iam_instance_profile"></a> [iam\_instance\_profile](#input\_iam\_instance\_profile) | IAM Instance Profile to launch the instance with. Specified as the name of the Instance Profile | `string` | `null` | no |
+| <a name="input_instance_initiated_shutdown_behavior"></a> [instance\_initiated\_shutdown\_behavior](#input\_instance\_initiated\_shutdown\_behavior) | Shutdown behavior for the instance. Amazon defaults this to stop for EBS-backed instances and terminate for instance-store instances. Cannot be set on instance-store instance | `string` | `null` | no |
+| <a name="input_instance_type"></a> [instance\_type](#input\_instance\_type) | The type of instance to start | `string` | `"t3.micro"` | no |
+| <a name="input_ipv6_address_count"></a> [ipv6\_address\_count](#input\_ipv6\_address\_count) | A number of IPv6 addresses to associate with the primary network interface. Amazon EC2 chooses the IPv6 addresses from the range of your subnet | `number` | `null` | no |
 | <a name="input_ipv6_addresses"></a> [ipv6\_addresses](#input\_ipv6\_addresses) | Specify one or more IPv6 addresses from the range of the subnet to associate with the primary network interface | `list(string)` | `null` | no |
-| <a name="input_key_name"></a> [key\_name](#input\_key\_name) | The key name to use for the instance | `string` | `""` | no |
+| <a name="input_key_name"></a> [key\_name](#input\_key\_name) | Key name of the Key Pair to use for the instance; which can be managed using the `aws_key_pair` resource | `string` | `null` | no |
+| <a name="input_launch_template"></a> [launch\_template](#input\_launch\_template) | Specifies a Launch Template to configure the instance. Parameters configured on this resource will override the corresponding parameters in the Launch Template | `map(string)` | `null` | no |
 | <a name="input_metadata_options"></a> [metadata\_options](#input\_metadata\_options) | Customize the metadata options of the instance | `map(string)` | `{}` | no |
 | <a name="input_monitoring"></a> [monitoring](#input\_monitoring) | If true, the launched EC2 instance will have detailed monitoring enabled | `bool` | `false` | no |
-| <a name="input_name"></a> [name](#input\_name) | Name to be used on all resources as prefix | `string` | n/a | yes |
+| <a name="input_name"></a> [name](#input\_name) | Name to be used on EC2 instance created | `string` | `""` | no |
 | <a name="input_network_interface"></a> [network\_interface](#input\_network\_interface) | Customize network interfaces to be attached at instance boot time | `list(map(string))` | `[]` | no |
-| <a name="input_num_suffix_format"></a> [num\_suffix\_format](#input\_num\_suffix\_format) | Numerical suffix format used as the volume and EC2 instance name suffix | `string` | `"-%d"` | no |
-| <a name="input_placement_group"></a> [placement\_group](#input\_placement\_group) | The Placement Group to start the instance in | `string` | `""` | no |
+| <a name="input_placement_group"></a> [placement\_group](#input\_placement\_group) | The Placement Group to start the instance in | `string` | `null` | no |
 | <a name="input_private_ip"></a> [private\_ip](#input\_private\_ip) | Private IP address to associate with the instance in a VPC | `string` | `null` | no |
-| <a name="input_private_ips"></a> [private\_ips](#input\_private\_ips) | A list of private IP address to associate with the instance in a VPC. Should match the number of instances. | `list(string)` | `[]` | no |
 | <a name="input_root_block_device"></a> [root\_block\_device](#input\_root\_block\_device) | Customize details about the root block device of the instance. See Block Devices below for details | `list(any)` | `[]` | no |
+| <a name="input_secondary_private_ips"></a> [secondary\_private\_ips](#input\_secondary\_private\_ips) | A list of secondary private IPv4 addresses to assign to the instance's primary network interface (eth0) in a VPC. Can only be assigned to the primary network interface (eth0) attached at instance creation, not a pre-existing network interface i.e. referenced in a `network_interface block` | `list(string)` | `null` | no |
 | <a name="input_source_dest_check"></a> [source\_dest\_check](#input\_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 |
-| <a name="input_subnet_id"></a> [subnet\_id](#input\_subnet\_id) | The VPC Subnet ID to launch in | `string` | `""` | no |
-| <a name="input_subnet_ids"></a> [subnet\_ids](#input\_subnet\_ids) | A list of VPC Subnet IDs to launch in | `list(string)` | `[]` | no |
+| <a name="input_subnet_id"></a> [subnet\_id](#input\_subnet\_id) | The VPC Subnet ID to launch in | `string` | `null` | no |
 | <a name="input_tags"></a> [tags](#input\_tags) | A mapping of tags to assign to the resource | `map(string)` | `{}` | no |
-| <a name="input_tenancy"></a> [tenancy](#input\_tenancy) | The tenancy of the instance (if the instance is running in a VPC). Available values: default, dedicated, host. | `string` | `"default"` | no |
-| <a name="input_use_num_suffix"></a> [use\_num\_suffix](#input\_use\_num\_suffix) | Always append numerical suffix to instance name, even if instance\_count is 1 | `bool` | `false` | no |
+| <a name="input_tenancy"></a> [tenancy](#input\_tenancy) | The tenancy of the instance (if the instance is running in a VPC). Available values: default, dedicated, host. | `string` | `null` | no |
+| <a name="input_timeouts"></a> [timeouts](#input\_timeouts) | Define maximum timeout for creating, updating, and deleting EC2 instance resources | `map(string)` | `{}` | no |
 | <a name="input_user_data"></a> [user\_data](#input\_user\_data) | The user data to provide when launching the instance. Do not pass gzip-compressed data via this argument; see user\_data\_base64 instead. | `string` | `null` | no |
 | <a name="input_user_data_base64"></a> [user\_data\_base64](#input\_user\_data\_base64) | Can be used instead of user\_data to pass base64-encoded binary data directly. Use this instead of user\_data whenever the value is not a valid UTF-8 string. For example, gzip-encoded user data must be base64-encoded and passed via this argument to avoid corruption. | `string` | `null` | no |
 | <a name="input_volume_tags"></a> [volume\_tags](#input\_volume\_tags) | A mapping of tags to assign to the devices created by the instance at launch time | `map(string)` | `{}` | no |
@@ -149,29 +178,17 @@ No modules.
 
 | Name | Description |
 |------|-------------|
-| <a name="output_arn"></a> [arn](#output\_arn) | List of ARNs of instances |
-| <a name="output_availability_zone"></a> [availability\_zone](#output\_availability\_zone) | List of availability zones of instances |
-| <a name="output_credit_specification"></a> [credit\_specification](#output\_credit\_specification) | List of credit specification of instances |
-| <a name="output_ebs_block_device_volume_ids"></a> [ebs\_block\_device\_volume\_ids](#output\_ebs\_block\_device\_volume\_ids) | List of volume IDs of EBS block devices of instances |
-| <a name="output_id"></a> [id](#output\_id) | List of IDs of instances |
-| <a name="output_instance_count"></a> [instance\_count](#output\_instance\_count) | Number of instances to launch specified as argument to this module |
-| <a name="output_instance_state"></a> [instance\_state](#output\_instance\_state) | List of instance states of instances |
-| <a name="output_ipv6_addresses"></a> [ipv6\_addresses](#output\_ipv6\_addresses) | List of assigned IPv6 addresses of instances |
-| <a name="output_key_name"></a> [key\_name](#output\_key\_name) | List of key names of instances |
-| <a name="output_metadata_options"></a> [metadata\_options](#output\_metadata\_options) | List of metadata options of instances |
-| <a name="output_password_data"></a> [password\_data](#output\_password\_data) | List of Base-64 encoded encrypted password data for the instance |
-| <a name="output_placement_group"></a> [placement\_group](#output\_placement\_group) | List of placement groups of instances |
-| <a name="output_primary_network_interface_id"></a> [primary\_network\_interface\_id](#output\_primary\_network\_interface\_id) | List of IDs of the primary network interface of instances |
-| <a name="output_private_dns"></a> [private\_dns](#output\_private\_dns) | List of private DNS names assigned to the instances. Can only be used inside the Amazon EC2, and only available if you've enabled DNS hostnames for your VPC |
-| <a name="output_private_ip"></a> [private\_ip](#output\_private\_ip) | List of private IP addresses assigned to the instances |
-| <a name="output_public_dns"></a> [public\_dns](#output\_public\_dns) | List of public DNS names assigned to the instances. For EC2-VPC, this is only available if you've enabled DNS hostnames for your VPC |
-| <a name="output_public_ip"></a> [public\_ip](#output\_public\_ip) | List of public IP addresses assigned to the instances, if applicable |
-| <a name="output_root_block_device_volume_ids"></a> [root\_block\_device\_volume\_ids](#output\_root\_block\_device\_volume\_ids) | List of volume IDs of root block devices of instances |
-| <a name="output_security_groups"></a> [security\_groups](#output\_security\_groups) | List of associated security groups of instances |
-| <a name="output_subnet_id"></a> [subnet\_id](#output\_subnet\_id) | List of IDs of VPC subnets of instances |
-| <a name="output_tags"></a> [tags](#output\_tags) | List of tags of instances |
-| <a name="output_volume_tags"></a> [volume\_tags](#output\_volume\_tags) | List of tags of volumes of instances |
-| <a name="output_vpc_security_group_ids"></a> [vpc\_security\_group\_ids](#output\_vpc\_security\_group\_ids) | List of associated security groups of instances, if running in non-default VPC |
+| <a name="output_arn"></a> [arn](#output\_arn) | The ARN of the instance |
+| <a name="output_capacity_reservation_specification"></a> [capacity\_reservation\_specification](#output\_capacity\_reservation\_specification) | Capacity reservation specification of the instance |
+| <a name="output_id"></a> [id](#output\_id) | The ID of the instance |
+| <a name="output_instance_state"></a> [instance\_state](#output\_instance\_state) | The state of the instance. One of: `pending`, `running`, `shutting-down`, `terminated`, `stopping`, `stopped` |
+| <a name="output_outpost_arn"></a> [outpost\_arn](#output\_outpost\_arn) | The ARN of the Outpost the instance is assigned to |
+| <a name="output_password_data"></a> [password\_data](#output\_password\_data) | Base-64 encoded encrypted password data for the instance. Useful for getting the administrator password for instances running Microsoft Windows. This attribute is only exported if `get_password_data` is true |
+| <a name="output_primary_network_interface_id"></a> [primary\_network\_interface\_id](#output\_primary\_network\_interface\_id) | The ID of the instance's primary network interface |
+| <a name="output_private_dns"></a> [private\_dns](#output\_private\_dns) | The private DNS name assigned to the instance. Can only be used inside the Amazon EC2, and only available if you've enabled DNS hostnames for your VPC |
+| <a name="output_public_dns"></a> [public\_dns](#output\_public\_dns) | The public DNS name assigned to the instance. For EC2-VPC, this is only available if you've enabled DNS hostnames for your VPC |
+| <a name="output_public_ip"></a> [public\_ip](#output\_public\_ip) | The public IP address assigned to the instance, if applicable. NOTE: If you are using an aws\_eip with your instance, you should refer to the EIP's address directly and not use `public_ip` as this field will change after the EIP is attached |
+| <a name="output_tags_all"></a> [tags\_all](#output\_tags\_all) | A map of tags assigned to the resource, including those inherited from the provider default\_tags configuration block |
 <!-- END OF PRE-COMMIT-TERRAFORM DOCS HOOK -->
 
 ## Authors

UPGRADE-3.0.md

+# Upgrade from v2.x to v3.x
+
+If you have any questions regarding this upgrade process, please consult the `examples` directory:
+
+- [Complete](https://github.com/terraform-aws-modules/terraform-aws-ec2-instance/tree/master/examples/complete)
+- [Volume Attachment](https://github.com/terraform-aws-modules/terraform-aws-ec2-instance/tree/master/examples/volume-attachment)
+
+If you find a bug, please open an issue with supporting configuration to reproduce.
+
+## List of backwards incompatible changes
+
+- Terraform v0.13.1 is now minimum supported version to take advantage of `count` and `for_each` arguments at module level
+
+### Variable and output changes
+
+1. Removed variables:
+
+   - `instance_count`
+   - `subnet_ids` (only need to use `subnet_id` now)
+   - `private_ips` (only need to use `private_ip` now)
+   - `use_num_suffix`
+   - `num_suffix_format`
+
+2. Renamed variables:
+
+   - `tags` -> `tags_all`
+
+3. Removed outputs:
+
+   - `availability_zone`
+   - `placement_group`
+   - `key_name`
+   - `ipv6_addresses`
+   - `private_ip`
+   - `security_groups`
+   - `vpc_security_group_ids`
+   - `subnet_id`
+   - `credit_specification`
+   - `metadata_options`
+   - `root_block_device_volume_ids`
+   - `ebs_block_device_volume_ids`
+   - `volume_tags`
+   - `instance_count`
+
+4. Renamed outputs:
+
+   :info: All outputs used to be lists, and are now singular outputs due to the removal of `count`
+
+## Upgrade State Migrations
+
+### Before 2.x Example
+
+```hcl
+module "ec2_upgrade" {
+  source  = "terraform-aws-modules/ec2-instance/aws"
+  version = "2.21.0"
+
+  instance_count = 3
+
+  name                        = local.name
+  ami                         = data.aws_ami.amazon_linux.id
+  instance_type               = "c5.large"
+  subnet_ids                  = module.vpc.private_subnets
+  vpc_security_group_ids      = [module.security_group.security_group_id]
+  associate_public_ip_address = true
+
+  tags = local.tags
+}
+```
+
+### After 3.x Example
+
+```hcl
+locals {
+  num_suffix_format = "-%d"
+  multiple_instances = {
+    0 = {
+      num_suffix    = 1
+      instance_type = "c5.large"
+      subnet_id     = element(module.vpc.private_subnets, 0)
+    }
+    1 = {
+      num_suffix    = 2
+      instance_type = "c5.large"
+      subnet_id     = element(module.vpc.private_subnets, 1)
+    }
+    2 = {
+      num_suffix    = 3
+      instance_type = "c5.large"
+      subnet_id     = element(module.vpc.private_subnets, 2)
+    }
+  }
+}
+
+module "ec2_upgrade" {
+  source = "../../"
+
+  for_each = local.multiple_instances
+
+  name = format("%s${local.num_suffix_format}", local.name, each.value.num_suffix)
+
+  ami                         = data.aws_ami.amazon_linux.id
+  instance_type               = each.value.instance_type
+  subnet_id                   = each.value.subnet_id
+  vpc_security_group_ids      = [module.security_group.security_group_id]
+  associate_public_ip_address = true
+
+  tags = local.tags
+}
+```
+
+To migrate from the `v2.x` version to `v3.x` version example shown above, the following state move commands can be performed to maintain the current resources without modification:
+
+```bash
+terraform state mv 'module.ec2_upgrade.aws_instance.this[0]' 'module.ec2_upgrade["0"].aws_instance.this[0]'
+terraform state mv 'module.ec2_upgrade.aws_instance.this[1]' 'module.ec2_upgrade["1"].aws_instance.this[0]'
+terraform state mv 'module.ec2_upgrade.aws_instance.this[2]' 'module.ec2_upgrade["2"].aws_instance.this[0]'
+```
+
+:info: Notes
+
+- In the `v2.x` example we use `subnet_ids` which is an array of subnets. These are mapped to the respective instance based on their index location; therefore in the `v3.x` example we are doing a similar index lookup to map back to the existing subnet used for that instance. This would also be the case for `private_ips`
+- In the `v3.x` example we have shown how users can continue to use the same naming scheme that is currently in use by the `v2.x` module. By moving the `num_suffix_format` into the module name itself inside a format function, users can continue to customize the names generated in a similar manner as that of the `v2.x` module.

examples/basic/README.md

-# Basic EC2 instance
-
-Configuration in this directory creates EC2 instances with different sets of arguments (with Elastic IP, with network interface attached, with credit specifications).
-
-## Usage
-
-To run this example you need to execute:
-
-```bash
-$ terraform init
-$ terraform plan
-$ terraform apply
-```
-
-Note that this example may create resources which can cost money. Run `terraform destroy` when you don't need these resources.
-
-<!-- BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK -->
-## Requirements
-
-| Name | Version |
-|------|---------|
-| <a name="requirement_terraform"></a> [terraform](#requirement\_terraform) | >= 0.12.6 |
-| <a name="requirement_aws"></a> [aws](#requirement\_aws) | >= 2.65 |
-
-## Providers
-
-| Name | Version |
-|------|---------|
-| <a name="provider_aws"></a> [aws](#provider\_aws) | >= 2.65 |
-
-## Modules
-
-| Name | Source | Version |
-|------|--------|---------|
-| <a name="module_ec2"></a> [ec2](#module\_ec2) | ../../ |  |
-| <a name="module_ec2_optimize_cpu"></a> [ec2\_optimize\_cpu](#module\_ec2\_optimize\_cpu) | ../../ |  |
-| <a name="module_ec2_with_metadata_options"></a> [ec2\_with\_metadata\_options](#module\_ec2\_with\_metadata\_options) | ../../ |  |
-| <a name="module_ec2_with_network_interface"></a> [ec2\_with\_network\_interface](#module\_ec2\_with\_network\_interface) | ../../ |  |
-| <a name="module_ec2_with_t2_unlimited"></a> [ec2\_with\_t2\_unlimited](#module\_ec2\_with\_t2\_unlimited) | ../../ |  |
-| <a name="module_ec2_with_t3_unlimited"></a> [ec2\_with\_t3\_unlimited](#module\_ec2\_with\_t3\_unlimited) | ../../ |  |
-| <a name="module_ec2_zero"></a> [ec2\_zero](#module\_ec2\_zero) | ../../ |  |
-| <a name="module_security_group"></a> [security\_group](#module\_security\_group) | terraform-aws-modules/security-group/aws | ~> 4.0 |
-
-## Resources
-
-| Name | Type |
-|------|------|
-| [aws_eip.this](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/eip) | resource |
-| [aws_kms_key.this](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/kms_key) | resource |
-| [aws_network_interface.this](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/network_interface) | resource |
-| [aws_placement_group.web](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/placement_group) | resource |
-| [aws_ami.amazon_linux](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/ami) | data source |
-| [aws_subnet_ids.all](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/subnet_ids) | data source |
-| [aws_vpc.default](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/vpc) | data source |
-
-## Inputs
-
-No inputs.
-
-## Outputs
-
-| Name | Description |
-|------|-------------|
-| <a name="output_credit_specification"></a> [credit\_specification](#output\_credit\_specification) | Credit specification of EC2 instance (empty list for not t2 instance types) |
-| <a name="output_credit_specification_t2_unlimited"></a> [credit\_specification\_t2\_unlimited](#output\_credit\_specification\_t2\_unlimited) | Credit specification of t2-type EC2 instance |
-| <a name="output_ebs_block_device_volume_ids"></a> [ebs\_block\_device\_volume\_ids](#output\_ebs\_block\_device\_volume\_ids) | List of volume IDs of EBS block devices of instances |
-| <a name="output_ids"></a> [ids](#output\_ids) | List of IDs of instances |
-| <a name="output_ids_t2"></a> [ids\_t2](#output\_ids\_t2) | List of IDs of t2-type instances |
-| <a name="output_instance_id"></a> [instance\_id](#output\_instance\_id) | EC2 instance ID |
-| <a name="output_instance_public_dns"></a> [instance\_public\_dns](#output\_instance\_public\_dns) | Public DNS name assigned to the EC2 instance |
-| <a name="output_metadata_options"></a> [metadata\_options](#output\_metadata\_options) | Metadata options for the instance |
-| <a name="output_metadata_options_custom"></a> [metadata\_options\_custom](#output\_metadata\_options\_custom) | Customized metadata options for the instance |
-| <a name="output_placement_group"></a> [placement\_group](#output\_placement\_group) | List of placement group |
-| <a name="output_public_dns"></a> [public\_dns](#output\_public\_dns) | List of public DNS names assigned to the instances |
-| <a name="output_root_block_device_volume_ids"></a> [root\_block\_device\_volume\_ids](#output\_root\_block\_device\_volume\_ids) | List of volume IDs of root block devices of instances |
-| <a name="output_t2_instance_id"></a> [t2\_instance\_id](#output\_t2\_instance\_id) | EC2 instance ID |
-| <a name="output_tags"></a> [tags](#output\_tags) | List of tags |
-| <a name="output_vpc_security_group_ids"></a> [vpc\_security\_group\_ids](#output\_vpc\_security\_group\_ids) | List of VPC security group ids assigned to the instances |
-<!-- END OF PRE-COMMIT-TERRAFORM DOCS HOOK -->

examples/basic/outputs.tf

-output "ids" {
-  description = "List of IDs of instances"
-  value       = module.ec2.id
-}
-
-output "ids_t2" {
-  description = "List of IDs of t2-type instances"
-  value       = module.ec2_with_t2_unlimited.id
-}
-
-output "public_dns" {
-  description = "List of public DNS names assigned to the instances"
-  value       = module.ec2.public_dns
-}
-
-output "vpc_security_group_ids" {
-  description = "List of VPC security group ids assigned to the instances"
-  value       = module.ec2.vpc_security_group_ids
-}
-
-output "root_block_device_volume_ids" {
-  description = "List of volume IDs of root block devices of instances"
-  value       = module.ec2.root_block_device_volume_ids
-}
-
-output "ebs_block_device_volume_ids" {
-  description = "List of volume IDs of EBS block devices of instances"
-  value       = module.ec2.ebs_block_device_volume_ids
-}
-
-output "tags" {
-  description = "List of tags"
-  value       = module.ec2.tags
-}
-
-output "placement_group" {
-  description = "List of placement group"
-  value       = module.ec2.placement_group
-}
-
-output "instance_id" {
-  description = "EC2 instance ID"
-  value       = module.ec2.id[0]
-}
-
-output "t2_instance_id" {
-  description = "EC2 instance ID"
-  value       = module.ec2_with_t2_unlimited.id[0]
-}
-
-output "instance_public_dns" {
-  description = "Public DNS name assigned to the EC2 instance"
-  value       = module.ec2.public_dns[0]
-}
-
-output "credit_specification" {
-  description = "Credit specification of EC2 instance (empty list for not t2 instance types)"
-  value       = module.ec2.credit_specification
-}
-
-output "credit_specification_t2_unlimited" {
-  description = "Credit specification of t2-type EC2 instance"
-  value       = module.ec2_with_t2_unlimited.credit_specification
-}
-
-output "metadata_options" {
-  description = "Metadata options for the instance"
-  value       = module.ec2.metadata_options
-}
-
-output "metadata_options_custom" {
-  description = "Customized metadata options for the instance"
-  value       = module.ec2_with_metadata_options.metadata_options
-}

examples/basic/versions.tf

-terraform {
-  required_version = ">= 0.12.6"
-
-  required_providers {
-    aws = ">= 2.65"
-  }
-}

examples/complete/README.md

+# Complete EC2 instance
+
+Configuration in this directory creates EC2 instances with different sets of arguments (with Elastic IP, with network interface attached, with credit specifications).
+
+## Usage
+
+To run this example you need to execute:
+
+```bash
+$ terraform init
+$ terraform plan
+$ terraform apply
+```
+
+Note that this example may create resources which can cost money. Run `terraform destroy` when you don't need these resources.
+
+<!-- BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK -->
+## Requirements
+
+| Name | Version |
+|------|---------|
+| <a name="requirement_terraform"></a> [terraform](#requirement\_terraform) | >= 0.13.1 |
+| <a name="requirement_aws"></a> [aws](#requirement\_aws) | >= 3.51 |
+
+## Providers
+
+| Name | Version |
+|------|---------|
+| <a name="provider_aws"></a> [aws](#provider\_aws) | >= 3.51 |
+
+## Modules
+
+| Name | Source | Version |
+|------|--------|---------|
+| <a name="module_ec2_complete"></a> [ec2\_complete](#module\_ec2\_complete) | ../../ |  |
+| <a name="module_ec2_disabled"></a> [ec2\_disabled](#module\_ec2\_disabled) | ../../ |  |
+| <a name="module_ec2_metadata_options"></a> [ec2\_metadata\_options](#module\_ec2\_metadata\_options) | ../../ |  |
+| <a name="module_ec2_multiple"></a> [ec2\_multiple](#module\_ec2\_multiple) | ../../ |  |
+| <a name="module_ec2_network_interface"></a> [ec2\_network\_interface](#module\_ec2\_network\_interface) | ../../ |  |
+| <a name="module_ec2_t2_unlimited"></a> [ec2\_t2\_unlimited](#module\_ec2\_t2\_unlimited) | ../../ |  |
+| <a name="module_ec2_t3_unlimited"></a> [ec2\_t3\_unlimited](#module\_ec2\_t3\_unlimited) | ../../ |  |
+| <a name="module_security_group"></a> [security\_group](#module\_security\_group) | terraform-aws-modules/security-group/aws | ~> 4.0 |
+| <a name="module_vpc"></a> [vpc](#module\_vpc) | terraform-aws-modules/vpc/aws | ~> 3.0 |
+
+## Resources
+
+| Name | Type |
+|------|------|
+| [aws_kms_key.this](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/kms_key) | resource |
+| [aws_network_interface.this](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/network_interface) | resource |
+| [aws_placement_group.web](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/placement_group) | resource |
+| [aws_ami.amazon_linux](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/ami) | data source |
+
+## Inputs
+
+No inputs.
+
+## Outputs
+
+| Name | Description |
+|------|-------------|
+| <a name="output_ec2_complete_arn"></a> [ec2\_complete\_arn](#output\_ec2\_complete\_arn) | The ARN of the instance |
+| <a name="output_ec2_complete_capacity_reservation_specification"></a> [ec2\_complete\_capacity\_reservation\_specification](#output\_ec2\_complete\_capacity\_reservation\_specification) | Capacity reservation specification of the instance |
+| <a name="output_ec2_complete_id"></a> [ec2\_complete\_id](#output\_ec2\_complete\_id) | The ID of the instance |
+| <a name="output_ec2_complete_instance_state"></a> [ec2\_complete\_instance\_state](#output\_ec2\_complete\_instance\_state) | The state of the instance. One of: `pending`, `running`, `shutting-down`, `terminated`, `stopping`, `stopped` |
+| <a name="output_ec2_complete_primary_network_interface_id"></a> [ec2\_complete\_primary\_network\_interface\_id](#output\_ec2\_complete\_primary\_network\_interface\_id) | The ID of the instance's primary network interface |
+| <a name="output_ec2_complete_private_dns"></a> [ec2\_complete\_private\_dns](#output\_ec2\_complete\_private\_dns) | The private DNS name assigned to the instance. Can only be used inside the Amazon EC2, and only available if you've enabled DNS hostnames for your VPC |
+| <a name="output_ec2_complete_public_dns"></a> [ec2\_complete\_public\_dns](#output\_ec2\_complete\_public\_dns) | The public DNS name assigned to the instance. For EC2-VPC, this is only available if you've enabled DNS hostnames for your VPC |
+| <a name="output_ec2_complete_public_ip"></a> [ec2\_complete\_public\_ip](#output\_ec2\_complete\_public\_ip) | The public IP address assigned to the instance, if applicable. NOTE: If you are using an aws\_eip with your instance, you should refer to the EIP's address directly and not use `public_ip` as this field will change after the EIP is attached |
+| <a name="output_ec2_complete_tags_all"></a> [ec2\_complete\_tags\_all](#output\_ec2\_complete\_tags\_all) | A map of tags assigned to the resource, including those inherited from the provider default\_tags configuration block |
+| <a name="output_ec2_multiple"></a> [ec2\_multiple](#output\_ec2\_multiple) | The full output of the `ec2_module` module |
+| <a name="output_ec2_t2_unlimited_arn"></a> [ec2\_t2\_unlimited\_arn](#output\_ec2\_t2\_unlimited\_arn) | The ARN of the instance |
+| <a name="output_ec2_t2_unlimited_capacity_reservation_specification"></a> [ec2\_t2\_unlimited\_capacity\_reservation\_specification](#output\_ec2\_t2\_unlimited\_capacity\_reservation\_specification) | Capacity reservation specification of the instance |
+| <a name="output_ec2_t2_unlimited_id"></a> [ec2\_t2\_unlimited\_id](#output\_ec2\_t2\_unlimited\_id) | The ID of the instance |
+| <a name="output_ec2_t2_unlimited_instance_state"></a> [ec2\_t2\_unlimited\_instance\_state](#output\_ec2\_t2\_unlimited\_instance\_state) | The state of the instance. One of: `pending`, `running`, `shutting-down`, `terminated`, `stopping`, `stopped` |
+| <a name="output_ec2_t2_unlimited_primary_network_interface_id"></a> [ec2\_t2\_unlimited\_primary\_network\_interface\_id](#output\_ec2\_t2\_unlimited\_primary\_network\_interface\_id) | The ID of the instance's primary network interface |
+| <a name="output_ec2_t2_unlimited_private_dns"></a> [ec2\_t2\_unlimited\_private\_dns](#output\_ec2\_t2\_unlimited\_private\_dns) | The private DNS name assigned to the instance. Can only be used inside the Amazon EC2, and only available if you've enabled DNS hostnames for your VPC |
+| <a name="output_ec2_t2_unlimited_public_dns"></a> [ec2\_t2\_unlimited\_public\_dns](#output\_ec2\_t2\_unlimited\_public\_dns) | The public DNS name assigned to the instance. For EC2-VPC, this is only available if you've enabled DNS hostnames for your VPC |
+| <a name="output_ec2_t2_unlimited_public_ip"></a> [ec2\_t2\_unlimited\_public\_ip](#output\_ec2\_t2\_unlimited\_public\_ip) | The public IP address assigned to the instance, if applicable. NOTE: If you are using an aws\_eip with your instance, you should refer to the EIP's address directly and not use `public_ip` as this field will change after the EIP is attached |
+| <a name="output_ec2_t2_unlimited_tags_all"></a> [ec2\_t2\_unlimited\_tags\_all](#output\_ec2\_t2\_unlimited\_tags\_all) | A map of tags assigned to the resource, including those inherited from the provider default\_tags configuration block |
+| <a name="output_ec2_t3_unlimited_arn"></a> [ec2\_t3\_unlimited\_arn](#output\_ec2\_t3\_unlimited\_arn) | The ARN of the instance |
+| <a name="output_ec2_t3_unlimited_capacity_reservation_specification"></a> [ec2\_t3\_unlimited\_capacity\_reservation\_specification](#output\_ec2\_t3\_unlimited\_capacity\_reservation\_specification) | Capacity reservation specification of the instance |
+| <a name="output_ec2_t3_unlimited_id"></a> [ec2\_t3\_unlimited\_id](#output\_ec2\_t3\_unlimited\_id) | The ID of the instance |
+| <a name="output_ec2_t3_unlimited_instance_state"></a> [ec2\_t3\_unlimited\_instance\_state](#output\_ec2\_t3\_unlimited\_instance\_state) | The state of the instance. One of: `pending`, `running`, `shutting-down`, `terminated`, `stopping`, `stopped` |
+| <a name="output_ec2_t3_unlimited_primary_network_interface_id"></a> [ec2\_t3\_unlimited\_primary\_network\_interface\_id](#output\_ec2\_t3\_unlimited\_primary\_network\_interface\_id) | The ID of the instance's primary network interface |
+| <a name="output_ec2_t3_unlimited_private_dns"></a> [ec2\_t3\_unlimited\_private\_dns](#output\_ec2\_t3\_unlimited\_private\_dns) | The private DNS name assigned to the instance. Can only be used inside the Amazon EC2, and only available if you've enabled DNS hostnames for your VPC |
+| <a name="output_ec2_t3_unlimited_public_dns"></a> [ec2\_t3\_unlimited\_public\_dns](#output\_ec2\_t3\_unlimited\_public\_dns) | The public DNS name assigned to the instance. For EC2-VPC, this is only available if you've enabled DNS hostnames for your VPC |
+| <a name="output_ec2_t3_unlimited_public_ip"></a> [ec2\_t3\_unlimited\_public\_ip](#output\_ec2\_t3\_unlimited\_public\_ip) | The public IP address assigned to the instance, if applicable. NOTE: If you are using an aws\_eip with your instance, you should refer to the EIP's address directly and not use `public_ip` as this field will change after the EIP is attached |
+| <a name="output_ec2_t3_unlimited_tags_all"></a> [ec2\_t3\_unlimited\_tags\_all](#output\_ec2\_t3\_unlimited\_tags\_all) | A map of tags assigned to the resource, including those inherited from the provider default\_tags configuration block |
+<!-- END OF PRE-COMMIT-TERRAFORM DOCS HOOK -->

examples/basic/main.tf → examples/complete/main.tf

 provider "aws" {
-  region = "eu-west-1"
+  region = local.region
 }
 
 locals {
-  user_data = <<EOF
-#!/bin/bash
-echo "Hello Terraform!"
-EOF
-}
+  name   = "example-ec2-complete"
+  region = "eu-west-1"
+
+  user_data = <<-EOT
+  #!/bin/bash
+  echo "Hello Terraform!"
+  EOT
 
-##################################################################
-# Data sources to get VPC, subnet, security group and AMI details
-##################################################################
-data "aws_vpc" "default" {
-  default = true
+  tags = {
+    Owner       = "user"
+    Environment = "dev"
+  }
 }
 
-data "aws_subnet_ids" "all" {
-  vpc_id = data.aws_vpc.default.id
+################################################################################
+# Supporting Resources
+################################################################################
+
+module "vpc" {
+  source  = "terraform-aws-modules/vpc/aws"
+  version = "~> 3.0"
+
+  name = local.name
+  cidr = "10.99.0.0/18"
+
+  azs              = ["${local.region}a", "${local.region}b", "${local.region}c"]
+  public_subnets   = ["10.99.0.0/24", "10.99.1.0/24", "10.99.2.0/24"]
+  private_subnets  = ["10.99.3.0/24", "10.99.4.0/24", "10.99.5.0/24"]
+  database_subnets = ["10.99.7.0/24", "10.99.8.0/24", "10.99.9.0/24"]
+
+  tags = local.tags
 }
 
 data "aws_ami" "amazon_linux" {
   most_recent = true
-
   owners      = ["amazon"]
 
   filter {
     name   = "name"
-
-    values = [
-      "amzn-ami-hvm-*-x86_64-gp2",
-    ]
-  }
-
-  filter {
-    name = "owner-alias"
-
-    values = [
-      "amazon",
-    ]
+    values = ["amzn-ami-hvm-*-x86_64-gp2"]
   }
 }
 
@@ -46,22 +50,19 @@ module "security_group" {
   source  = "terraform-aws-modules/security-group/aws"
   version = "~> 4.0"
 
-  name        = "example"
+  name        = local.name
   description = "Security group for example usage with EC2 instance"
-  vpc_id      = data.aws_vpc.default.id
+  vpc_id      = module.vpc.vpc_id
 
   ingress_cidr_blocks = ["0.0.0.0/0"]
   ingress_rules       = ["http-80-tcp", "all-icmp"]
   egress_rules        = ["all-all"]
-}
 
-resource "aws_eip" "this" {
-  vpc      = true
-  instance = module.ec2.id[0]
+  tags = local.tags
 }
 
 resource "aws_placement_group" "web" {
-  name     = "hunky-dory-pg"
+  name     = local.name
   strategy = "cluster"
 }
 
@@ -69,33 +70,52 @@ resource "aws_kms_key" "this" {
 }
 
 resource "aws_network_interface" "this" {
-  count = 1
+  subnet_id = element(module.vpc.private_subnets, 0)
+}
+
+################################################################################
+# EC2 Module
+################################################################################
 
-  subnet_id = tolist(data.aws_subnet_ids.all.ids)[count.index]
+module "ec2_disabled" {
+  source = "../../"
+
+  create = false
 }
 
-module "ec2" {
+module "ec2_complete" {
   source = "../../"
 
-  instance_count = 1
+  name = local.name
 
-  name          = "example-normal"
   ami                         = data.aws_ami.amazon_linux.id
-  instance_type = "c5.large"
-  subnet_id     = tolist(data.aws_subnet_ids.all.ids)[0]
-  #  private_ips                 = ["172.31.32.5", "172.31.46.20"]
+  instance_type               = "c5.4xlarge"
+  availability_zone           = element(module.vpc.azs, 0)
+  subnet_id                   = element(module.vpc.private_subnets, 0)
   vpc_security_group_ids      = [module.security_group.security_group_id]
-  associate_public_ip_address = true
   placement_group             = aws_placement_group.web.id
+  associate_public_ip_address = true
+
+  # only one of these can be enabled at a time
+  hibernation = true
+  # enclave_options_enabled = true
 
   user_data_base64 = base64encode(local.user_data)
 
+  cpu_core_count       = 2 # default 4
+  cpu_threads_per_core = 1 # default 2
+
+  capacity_reservation_specification = {
+    capacity_reservation_preference = "open"
+  }
+
   enable_volume_tags = false
   root_block_device = [
     {
+      encrypted   = true
       volume_type = "gp3"
-      volume_size = 10
       throughput  = 200
+      volume_size = 50
       tags = {
         Name = "my-root-block"
       }
@@ -113,119 +133,134 @@ module "ec2" {
     }
   ]
 
-  tags = {
-    "Env"      = "Private"
-    "Location" = "Secret"
-  }
+  tags = local.tags
 }
 
-module "ec2_with_t2_unlimited" {
+module "ec2_network_interface" {
   source = "../../"
 
-  instance_count = 1
+  name = "${local.name}-network-interface"
 
-  name          = "example-t2-unlimited"
   ami           = data.aws_ami.amazon_linux.id
-  instance_type = "t2.micro"
-  cpu_credits   = "unlimited"
-  subnet_id     = tolist(data.aws_subnet_ids.all.ids)[0]
-  #  private_ip = "172.31.32.10"
-  vpc_security_group_ids      = [module.security_group.security_group_id]
-  associate_public_ip_address = true
-}
-
-module "ec2_with_t3_unlimited" {
-  source = "../../"
+  instance_type = "c5.large"
 
-  instance_count = 1
+  network_interface = [
+    {
+      device_index          = 0
+      network_interface_id  = aws_network_interface.this.id
+      delete_on_termination = false
+    }
+  ]
 
-  name                        = "example-t3-unlimited"
-  ami                         = data.aws_ami.amazon_linux.id
-  instance_type               = "t3.large"
-  cpu_credits                 = "unlimited"
-  subnet_id                   = tolist(data.aws_subnet_ids.all.ids)[0]
-  vpc_security_group_ids      = [module.security_group.security_group_id]
-  associate_public_ip_address = true
+  tags = local.tags
 }
 
-module "ec2_with_metadata_options" {
+module "ec2_metadata_options" {
   source = "../../"
 
-  instance_count = 1
+  name = "${local.name}-metadata-options"
 
-  name                        = "example-metadata_options"
   ami                    = data.aws_ami.amazon_linux.id
-  instance_type               = "t2.small"
-  subnet_id                   = tolist(data.aws_subnet_ids.all.ids)[0]
+  instance_type          = "c5.4xlarge"
+  subnet_id              = element(module.vpc.private_subnets, 0)
   vpc_security_group_ids = [module.security_group.security_group_id]
-  associate_public_ip_address = true
 
   metadata_options = {
     http_endpoint               = "enabled"
     http_tokens                 = "required"
     http_put_response_hop_limit = 8
   }
-}
 
-module "ec2_with_network_interface" {
-  source = "../../"
-
-  instance_count = 1
-
-  name            = "example-network"
-  ami             = data.aws_ami.amazon_linux.id
-  instance_type   = "c5.large"
-  placement_group = aws_placement_group.web.id
-
-  network_interface = [
-    {
-      device_index          = 0
-      network_interface_id  = aws_network_interface.this[0].id
-      delete_on_termination = false
-    }
-  ]
+  tags = local.tags
 }
 
-# This instance won't be created
-module "ec2_zero" {
+module "ec2_t2_unlimited" {
   source = "../../"
 
-  instance_count = 0
+  name = "${local.name}-t2-unlimited"
 
-  name                   = "example-zero"
   ami                         = data.aws_ami.amazon_linux.id
-  instance_type          = "c5.large"
-  subnet_id              = tolist(data.aws_subnet_ids.all.ids)[0]
+  instance_type               = "t2.micro"
+  cpu_credits                 = "unlimited"
+  subnet_id                   = element(module.vpc.private_subnets, 0)
   vpc_security_group_ids      = [module.security_group.security_group_id]
+  associate_public_ip_address = true
+
+  tags = local.tags
 }
 
-module "ec2_optimize_cpu" {
+module "ec2_t3_unlimited" {
   source = "../../"
 
-  instance_count = 1
+  name = "${local.name}-t3-unlimited"
 
-  name          = "example-optimize-cpu"
   ami                         = data.aws_ami.amazon_linux.id
-  instance_type = "c4.2xlarge"
-  subnet_id     = tolist(data.aws_subnet_ids.all.ids)[0]
-
+  instance_type               = "t3.micro"
+  cpu_credits                 = "unlimited"
+  subnet_id                   = element(module.vpc.private_subnets, 0)
   vpc_security_group_ids      = [module.security_group.security_group_id]
   associate_public_ip_address = true
-  placement_group             = aws_placement_group.web.id
 
-  user_data_base64 = base64encode(local.user_data)
+  tags = local.tags
+}
+
+################################################################################
+# EC2 Module - multiple instances with `for_each`
+################################################################################
 
+locals {
+  multiple_instances = {
+    one = {
+      instance_type     = "t3.micro"
+      availability_zone = element(module.vpc.azs, 0)
+      subnet_id         = element(module.vpc.private_subnets, 0)
       root_block_device = [
         {
+          encrypted   = true
+          volume_type = "gp3"
+          throughput  = 200
+          volume_size = 50
+          tags = {
+            Name = "my-root-block"
+          }
+        }
+      ]
+    }
+    two = {
+      instance_type     = "t3.small"
+      availability_zone = element(module.vpc.azs, 1)
+      subnet_id         = element(module.vpc.private_subnets, 1)
+      root_block_device = [
+        {
+          encrypted   = true
           volume_type = "gp2"
-      volume_size = 10
-    },
+          volume_size = 50
+        }
       ]
-  cpu_core_count       = 2 # default 4
-  cpu_threads_per_core = 1 # default 2
-
-  tags = {
-    "Env"      = "Private"
-    "Location" = "Secret"
     }
+    three = {
+      instance_type     = "t3.medium"
+      availability_zone = element(module.vpc.azs, 2)
+      subnet_id         = element(module.vpc.private_subnets, 2)
+    }
+  }
+}
+
+module "ec2_multiple" {
+  source = "../../"
+
+  for_each = local.multiple_instances
+
+  name = "${local.name}-multi-${each.key}"
+
+  ami                    = data.aws_ami.amazon_linux.id
+  instance_type          = each.value.instance_type
+  availability_zone      = each.value.availability_zone
+  subnet_id              = each.value.subnet_id
+  vpc_security_group_ids = [module.security_group.security_group_id]
+
+  enable_volume_tags = false
+  root_block_device  = lookup(each.value, "root_block_device", [])
+
+  tags = local.tags
 }

examples/complete/outputs.tf

+# EC2 Complete
+output "ec2_complete_id" {
+  description = "The ID of the instance"
+  value       = module.ec2_complete.id
+}
+
+output "ec2_complete_arn" {
+  description = "The ARN of the instance"
+  value       = module.ec2_complete.arn
+}
+
+output "ec2_complete_capacity_reservation_specification" {
+  description = "Capacity reservation specification of the instance"
+  value       = module.ec2_complete.capacity_reservation_specification
+}
+
+output "ec2_complete_instance_state" {
+  description = "The state of the instance. One of: `pending`, `running`, `shutting-down`, `terminated`, `stopping`, `stopped`"
+  value       = module.ec2_complete.instance_state
+}
+
+output "ec2_complete_primary_network_interface_id" {
+  description = "The ID of the instance's primary network interface"
+  value       = module.ec2_complete.primary_network_interface_id
+}
+
+output "ec2_complete_private_dns" {
+  description = "The private DNS name assigned to the instance. Can only be used inside the Amazon EC2, and only available if you've enabled DNS hostnames for your VPC"
+  value       = module.ec2_complete.private_dns
+}
+
+output "ec2_complete_public_dns" {
+  description = "The public DNS name assigned to the instance. For EC2-VPC, this is only available if you've enabled DNS hostnames for your VPC"
+  value       = module.ec2_complete.public_dns
+}
+
+output "ec2_complete_public_ip" {
+  description = "The public IP address assigned to the instance, if applicable. NOTE: If you are using an aws_eip with your instance, you should refer to the EIP's address directly and not use `public_ip` as this field will change after the EIP is attached"
+  value       = module.ec2_complete.public_ip
+}
+
+output "ec2_complete_tags_all" {
+  description = "A map of tags assigned to the resource, including those inherited from the provider default_tags configuration block"
+  value       = module.ec2_complete.tags_all
+}
+
+# EC2 T2 Unlimited
+output "ec2_t2_unlimited_id" {
+  description = "The ID of the instance"
+  value       = module.ec2_t2_unlimited.id
+}
+
+output "ec2_t2_unlimited_arn" {
+  description = "The ARN of the instance"
+  value       = module.ec2_t2_unlimited.arn
+}
+
+output "ec2_t2_unlimited_capacity_reservation_specification" {
+  description = "Capacity reservation specification of the instance"
+  value       = module.ec2_t2_unlimited.capacity_reservation_specification
+}
+
+output "ec2_t2_unlimited_instance_state" {
+  description = "The state of the instance. One of: `pending`, `running`, `shutting-down`, `terminated`, `stopping`, `stopped`"
+  value       = module.ec2_t2_unlimited.instance_state
+}
+
+output "ec2_t2_unlimited_primary_network_interface_id" {
+  description = "The ID of the instance's primary network interface"
+  value       = module.ec2_t2_unlimited.primary_network_interface_id
+}
+
+output "ec2_t2_unlimited_private_dns" {
+  description = "The private DNS name assigned to the instance. Can only be used inside the Amazon EC2, and only available if you've enabled DNS hostnames for your VPC"
+  value       = module.ec2_t2_unlimited.private_dns
+}
+
+output "ec2_t2_unlimited_public_dns" {
+  description = "The public DNS name assigned to the instance. For EC2-VPC, this is only available if you've enabled DNS hostnames for your VPC"
+  value       = module.ec2_t2_unlimited.public_dns
+}
+
+output "ec2_t2_unlimited_public_ip" {
+  description = "The public IP address assigned to the instance, if applicable. NOTE: If you are using an aws_eip with your instance, you should refer to the EIP's address directly and not use `public_ip` as this field will change after the EIP is attached"
+  value       = module.ec2_t2_unlimited.public_ip
+}
+
+output "ec2_t2_unlimited_tags_all" {
+  description = "A map of tags assigned to the resource, including those inherited from the provider default_tags configuration block"
+  value       = module.ec2_t2_unlimited.tags_all
+}
+
+# EC2 T3 Unlimited
+output "ec2_t3_unlimited_id" {
+  description = "The ID of the instance"
+  value       = module.ec2_t3_unlimited.id
+}
+
+output "ec2_t3_unlimited_arn" {
+  description = "The ARN of the instance"
+  value       = module.ec2_t3_unlimited.arn
+}
+
+output "ec2_t3_unlimited_capacity_reservation_specification" {
+  description = "Capacity reservation specification of the instance"
+  value       = module.ec2_t3_unlimited.capacity_reservation_specification
+}
+
+output "ec2_t3_unlimited_instance_state" {
+  description = "The state of the instance. One of: `pending`, `running`, `shutting-down`, `terminated`, `stopping`, `stopped`"
+  value       = module.ec2_t3_unlimited.instance_state
+}
+
+output "ec2_t3_unlimited_primary_network_interface_id" {
+  description = "The ID of the instance's primary network interface"
+  value       = module.ec2_t3_unlimited.primary_network_interface_id
+}
+
+output "ec2_t3_unlimited_private_dns" {
+  description = "The private DNS name assigned to the instance. Can only be used inside the Amazon EC2, and only available if you've enabled DNS hostnames for your VPC"
+  value       = module.ec2_t3_unlimited.private_dns
+}
+
+output "ec2_t3_unlimited_public_dns" {
+  description = "The public DNS name assigned to the instance. For EC2-VPC, this is only available if you've enabled DNS hostnames for your VPC"
+  value       = module.ec2_t3_unlimited.public_dns
+}
+
+output "ec2_t3_unlimited_public_ip" {
+  description = "The public IP address assigned to the instance, if applicable. NOTE: If you are using an aws_eip with your instance, you should refer to the EIP's address directly and not use `public_ip` as this field will change after the EIP is attached"
+  value       = module.ec2_t3_unlimited.public_ip
+}
+
+output "ec2_t3_unlimited_tags_all" {
+  description = "A map of tags assigned to the resource, including those inherited from the provider default_tags configuration block"
+  value       = module.ec2_t3_unlimited.tags_all
+}
+
+# EC2 Multiple
+output "ec2_multiple" {
+  description = "The full output of the `ec2_module` module"
+  value       = module.ec2_multiple
+}

examples/complete/versions.tf

+terraform {
+  required_version = ">= 0.13.1"
+
+  required_providers {
+    aws = {
+      source  = "hashicorp/aws"
+      version = ">= 3.51"
+    }
+  }
+}

examples/volume-attachment/README.md

@@ -2,8 +2,6 @@
 
 Configuration in this directory creates EC2 instances, EBS volume and attach it together.
 
-Unspecified arguments for security group id and subnet are inherited from the default VPC.
-
 This example outputs instance id and EBS volume id.
 
 ## Usage
@@ -23,14 +21,14 @@ Note that this example may create resources which can cost money. Run `terraform
 
 | Name | Version |
 |------|---------|
-| <a name="requirement_terraform"></a> [terraform](#requirement\_terraform) | >= 0.12.6 |
-| <a name="requirement_aws"></a> [aws](#requirement\_aws) | >= 2.65 |
+| <a name="requirement_terraform"></a> [terraform](#requirement\_terraform) | >= 0.13.1 |
+| <a name="requirement_aws"></a> [aws](#requirement\_aws) | >= 3.51 |
 
 ## Providers
 
 | Name | Version |
 |------|---------|
-| <a name="provider_aws"></a> [aws](#provider\_aws) | >= 2.65 |
+| <a name="provider_aws"></a> [aws](#provider\_aws) | >= 3.51 |
 
 ## Modules
 
@@ -38,6 +36,7 @@ Note that this example may create resources which can cost money. Run `terraform
 |------|--------|---------|
 | <a name="module_ec2"></a> [ec2](#module\_ec2) | ../../ |  |
 | <a name="module_security_group"></a> [security\_group](#module\_security\_group) | terraform-aws-modules/security-group/aws | ~> 4.0 |
+| <a name="module_vpc"></a> [vpc](#module\_vpc) | terraform-aws-modules/vpc/aws | ~> 3.0 |
 
 ## Resources
 
@@ -46,20 +45,22 @@ Note that this example may create resources which can cost money. Run `terraform
 | [aws_ebs_volume.this](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/ebs_volume) | resource |
 | [aws_volume_attachment.this](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/volume_attachment) | resource |
 | [aws_ami.amazon_linux](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/ami) | data source |
-| [aws_subnet_ids.all](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/subnet_ids) | data source |
-| [aws_vpc.default](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/vpc) | data source |
 
 ## Inputs
 
-| Name | Description | Type | Default | Required |
-|------|-------------|------|---------|:--------:|
-| <a name="input_instances_number"></a> [instances\_number](#input\_instances\_number) | NUmber of instances | `number` | `1` | no |
+No inputs.
 
 ## Outputs
 
 | Name | Description |
 |------|-------------|
-| <a name="output_ebs_volume_attachment_id"></a> [ebs\_volume\_attachment\_id](#output\_ebs\_volume\_attachment\_id) | The volume ID |
-| <a name="output_ebs_volume_attachment_instance_id"></a> [ebs\_volume\_attachment\_instance\_id](#output\_ebs\_volume\_attachment\_instance\_id) | The instance ID |
-| <a name="output_instances_public_ips"></a> [instances\_public\_ips](#output\_instances\_public\_ips) | Public IPs assigned to the EC2 instance |
+| <a name="output_ec2_arn"></a> [ec2\_arn](#output\_ec2\_arn) | The ARN of the instance |
+| <a name="output_ec2_capacity_reservation_specification"></a> [ec2\_capacity\_reservation\_specification](#output\_ec2\_capacity\_reservation\_specification) | Capacity reservation specification of the instance |
+| <a name="output_ec2_id"></a> [ec2\_id](#output\_ec2\_id) | The ID of the instance |
+| <a name="output_ec2_instance_state"></a> [ec2\_instance\_state](#output\_ec2\_instance\_state) | The state of the instance. One of: `pending`, `running`, `shutting-down`, `terminated`, `stopping`, `stopped` |
+| <a name="output_ec2_primary_network_interface_id"></a> [ec2\_primary\_network\_interface\_id](#output\_ec2\_primary\_network\_interface\_id) | The ID of the instance's primary network interface |
+| <a name="output_ec2_private_dns"></a> [ec2\_private\_dns](#output\_ec2\_private\_dns) | The private DNS name assigned to the instance. Can only be used inside the Amazon EC2, and only available if you've enabled DNS hostnames for your VPC |
+| <a name="output_ec2_public_dns"></a> [ec2\_public\_dns](#output\_ec2\_public\_dns) | The public DNS name assigned to the instance. For EC2-VPC, this is only available if you've enabled DNS hostnames for your VPC |
+| <a name="output_ec2_public_ip"></a> [ec2\_public\_ip](#output\_ec2\_public\_ip) | The public IP address assigned to the instance, if applicable. NOTE: If you are using an aws\_eip with your instance, you should refer to the EIP's address directly and not use `public_ip` as this field will change after the EIP is attached |
+| <a name="output_ec2_tags_all"></a> [ec2\_tags\_all](#output\_ec2\_tags\_all) | A map of tags assigned to the resource, including those inherited from the provider default\_tags configuration block |
 <!-- END OF PRE-COMMIT-TERRAFORM DOCS HOOK -->

examples/volume-attachment/main.tf

 provider "aws" {
-  region = "eu-west-1"
+  region = local.region
 }
 
-##################################################################
-# Data sources to get VPC, subnet, security group and AMI details
-##################################################################
-data "aws_vpc" "default" {
-  default = true
+locals {
+  availability_zone = "${local.region}a"
+  name              = "example-ec2-volume-attachment"
+  region            = "eu-west-1"
+  tags = {
+    Owner       = "user"
+    Environment = "dev"
+  }
 }
 
-data "aws_subnet_ids" "all" {
-  vpc_id = data.aws_vpc.default.id
+################################################################################
+# Supporting Resources
+################################################################################
+
+module "vpc" {
+  source  = "terraform-aws-modules/vpc/aws"
+  version = "~> 3.0"
+
+  name = local.name
+  cidr = "10.99.0.0/18"
+
+  azs              = ["${local.region}a", "${local.region}b", "${local.region}c"]
+  public_subnets   = ["10.99.0.0/24", "10.99.1.0/24", "10.99.2.0/24"]
+  private_subnets  = ["10.99.3.0/24", "10.99.4.0/24", "10.99.5.0/24"]
+  database_subnets = ["10.99.7.0/24", "10.99.8.0/24", "10.99.9.0/24"]
+
+  tags = local.tags
 }
 
 data "aws_ami" "amazon_linux" {
   most_recent = true
-
   owners      = ["amazon"]
 
   filter {
     name   = "name"
-
-    values = [
-      "amzn-ami-hvm-*-x86_64-gp2",
-    ]
-  }
-
-  filter {
-    name = "owner-alias"
-
-    values = [
-      "amazon",
-    ]
+    values = ["amzn-ami-hvm-*-x86_64-gp2"]
   }
 }
 
@@ -39,39 +45,45 @@ module "security_group" {
   source  = "terraform-aws-modules/security-group/aws"
   version = "~> 4.0"
 
-  name        = "example"
+  name        = local.name
   description = "Security group for example usage with EC2 instance"
-  vpc_id      = data.aws_vpc.default.id
+  vpc_id      = module.vpc.vpc_id
 
   ingress_cidr_blocks = ["0.0.0.0/0"]
   ingress_rules       = ["http-80-tcp", "all-icmp"]
   egress_rules        = ["all-all"]
+
+  tags = local.tags
 }
 
+################################################################################
+# EC2 Module
+################################################################################
+
 module "ec2" {
   source = "../../"
 
-  instance_count = var.instances_number
+  name = local.name
 
-  name                        = "example-with-ebs"
   ami                         = data.aws_ami.amazon_linux.id
   instance_type               = "c5.large"
-  subnet_id                   = tolist(data.aws_subnet_ids.all.ids)[0]
+  availability_zone           = local.availability_zone
+  subnet_id                   = element(module.vpc.private_subnets, 0)
   vpc_security_group_ids      = [module.security_group.security_group_id]
   associate_public_ip_address = true
+
+  tags = local.tags
 }
 
 resource "aws_volume_attachment" "this" {
-  count = var.instances_number
-
   device_name = "/dev/sdh"
-  volume_id   = aws_ebs_volume.this[count.index].id
-  instance_id = module.ec2.id[count.index]
+  volume_id   = aws_ebs_volume.this.id
+  instance_id = module.ec2.id
 }
 
 resource "aws_ebs_volume" "this" {
-  count = var.instances_number
-
-  availability_zone = module.ec2.availability_zone[count.index]
+  availability_zone = local.availability_zone
   size              = 1
+
+  tags = local.tags
 }

examples/volume-attachment/outputs.tf

-output "instances_public_ips" {
-  description = "Public IPs assigned to the EC2 instance"
-  value       = module.ec2.public_ip
+# EC2
+output "ec2_id" {
+  description = "The ID of the instance"
+  value       = module.ec2.id
+}
+
+output "ec2_arn" {
+  description = "The ARN of the instance"
+  value       = module.ec2.arn
+}
+
+output "ec2_capacity_reservation_specification" {
+  description = "Capacity reservation specification of the instance"
+  value       = module.ec2.capacity_reservation_specification
+}
+
+output "ec2_instance_state" {
+  description = "The state of the instance. One of: `pending`, `running`, `shutting-down`, `terminated`, `stopping`, `stopped`"
+  value       = module.ec2.instance_state
 }
 
-output "ebs_volume_attachment_id" {
-  description = "The volume ID"
-  value       = aws_volume_attachment.this.*.volume_id
+output "ec2_primary_network_interface_id" {
+  description = "The ID of the instance's primary network interface"
+  value       = module.ec2.primary_network_interface_id
 }
 
-output "ebs_volume_attachment_instance_id" {
-  description = "The instance ID"
-  value       = aws_volume_attachment.this.*.instance_id
+output "ec2_private_dns" {
+  description = "The private DNS name assigned to the instance. Can only be used inside the Amazon EC2, and only available if you've enabled DNS hostnames for your VPC"
+  value       = module.ec2.private_dns
 }
 
+output "ec2_public_dns" {
+  description = "The public DNS name assigned to the instance. For EC2-VPC, this is only available if you've enabled DNS hostnames for your VPC"
+  value       = module.ec2.public_dns
+}
+
+output "ec2_public_ip" {
+  description = "The public IP address assigned to the instance, if applicable. NOTE: If you are using an aws_eip with your instance, you should refer to the EIP's address directly and not use `public_ip` as this field will change after the EIP is attached"
+  value       = module.ec2.public_ip
+}
+
+output "ec2_tags_all" {
+  description = "A map of tags assigned to the resource, including those inherited from the provider default_tags configuration block"
+  value       = module.ec2.tags_all
+}

examples/volume-attachment/variables.tf

-variable "instances_number" {
-  description = "NUmber of instances"
-  type        = number
-  default     = 1
-}

examples/volume-attachment/versions.tf

 terraform {
-  required_version = ">= 0.12.6"
+  required_version = ">= 0.13.1"
 
   required_providers {
-    aws = ">= 2.65"
+    aws = {
+      source  = "hashicorp/aws"
+      version = ">= 3.51"
+    }
   }
 }

main.tf

@@ -3,29 +3,47 @@ locals {
 }
 
 resource "aws_instance" "this" {
-  count = var.instance_count
+  count = var.create ? 1 : 0
 
   ami                  = var.ami
   instance_type        = var.instance_type
+  cpu_core_count       = var.cpu_core_count
+  cpu_threads_per_core = var.cpu_threads_per_core
   user_data            = var.user_data
   user_data_base64     = var.user_data_base64
-  subnet_id = length(var.network_interface) > 0 ? null : element(
-    distinct(compact(concat([var.subnet_id], var.subnet_ids))),
-    count.index,
-  )
+  hibernation          = var.hibernation
+
+  availability_zone      = var.availability_zone
+  subnet_id              = var.subnet_id
+  vpc_security_group_ids = var.vpc_security_group_ids
+
   key_name             = var.key_name
   monitoring           = var.monitoring
   get_password_data    = var.get_password_data
-  vpc_security_group_ids = var.vpc_security_group_ids
   iam_instance_profile = var.iam_instance_profile
 
   associate_public_ip_address = var.associate_public_ip_address
-  private_ip                  = length(var.private_ips) > 0 ? element(var.private_ips, count.index) : var.private_ip
+  private_ip                  = var.private_ip
+  secondary_private_ips       = var.secondary_private_ips
   ipv6_address_count          = var.ipv6_address_count
   ipv6_addresses              = var.ipv6_addresses
 
   ebs_optimized = var.ebs_optimized
 
+  dynamic "capacity_reservation_specification" {
+    for_each = var.capacity_reservation_specification != null ? [var.capacity_reservation_specification] : []
+    content {
+      capacity_reservation_preference = lookup(capacity_reservation_specification.value, "capacity_reservation_preference", null)
+
+      dynamic "capacity_reservation_target" {
+        for_each = lookup(capacity_reservation_specification.value, "capacity_reservation_target", [])
+        content {
+          capacity_reservation_id = lookup(capacity_reservation_target.value, "capacity_reservation_id", null)
+        }
+      }
+    }
+  }
+
   dynamic "root_block_device" {
     for_each = var.root_block_device
     content {
@@ -65,7 +83,7 @@ resource "aws_instance" "this" {
   }
 
   dynamic "metadata_options" {
-    for_each = length(keys(var.metadata_options)) == 0 ? [] : [var.metadata_options]
+    for_each = var.metadata_options != null ? [var.metadata_options] : []
     content {
       http_endpoint               = lookup(metadata_options.value, "http_endpoint", "enabled")
       http_tokens                 = lookup(metadata_options.value, "http_tokens", "optional")
@@ -82,29 +100,36 @@ resource "aws_instance" "this" {
     }
   }
 
+  dynamic "launch_template" {
+    for_each = var.launch_template != null ? [var.launch_template] : []
+    content {
+      id      = lookup(var.launch_template, "id", null)
+      name    = lookup(var.launch_template, "name", null)
+      version = lookup(var.launch_template, "version", null)
+    }
+  }
+
+  enclave_options {
+    enabled = var.enclave_options_enabled
+  }
+
   source_dest_check                    = length(var.network_interface) > 0 ? null : var.source_dest_check
   disable_api_termination              = var.disable_api_termination
   instance_initiated_shutdown_behavior = var.instance_initiated_shutdown_behavior
   placement_group                      = var.placement_group
   tenancy                              = var.tenancy
-  cpu_core_count                       = var.cpu_core_count
-  cpu_threads_per_core                 = var.cpu_threads_per_core
-
-  tags = merge(
-    {
-      "Name" = var.instance_count > 1 || var.use_num_suffix ? format("%s${var.num_suffix_format}", var.name, count.index + 1) : var.name
-    },
-    var.tags,
-  )
-
-  volume_tags = var.enable_volume_tags ? merge(
-    {
-      "Name" = var.instance_count > 1 || var.use_num_suffix ? format("%s${var.num_suffix_format}", var.name, count.index + 1) : var.name
-    },
-    var.volume_tags,
-  ) : null
+  host_id                              = var.host_id
 
   credit_specification {
     cpu_credits = local.is_t_instance_type ? var.cpu_credits : null
   }
+
+  timeouts {
+    create = lookup(var.timeouts, "create", null)
+    update = lookup(var.timeouts, "update", null)
+    delete = lookup(var.timeouts, "delete", null)
+  }
+
+  tags        = merge({ "Name" = var.name }, var.tags)
+  volume_tags = var.enable_volume_tags ? merge({ "Name" = var.name }, var.volume_tags) : null
 }

outputs.tf

 output "id" {
-  description = "List of IDs of instances"
-  value       = aws_instance.this.*.id
+  description = "The ID of the instance"
+  value       = element(concat(aws_instance.this.*.id, [""]), 0)
 }
 
 output "arn" {
-  description = "List of ARNs of instances"
-  value       = aws_instance.this.*.arn
+  description = "The ARN of the instance"
+  value       = element(concat(aws_instance.this.*.arn, [""]), 0)
 }
 
-output "availability_zone" {
-  description = "List of availability zones of instances"
-  value       = aws_instance.this.*.availability_zone
+output "capacity_reservation_specification" {
+  description = "Capacity reservation specification of the instance"
+  value       = element(concat(aws_instance.this.*.capacity_reservation_specification, [""]), 0)
 }
 
-output "placement_group" {
-  description = "List of placement groups of instances"
-  value       = aws_instance.this.*.placement_group
+output "instance_state" {
+  description = "The state of the instance. One of: `pending`, `running`, `shutting-down`, `terminated`, `stopping`, `stopped`"
+  value       = element(concat(aws_instance.this.*.instance_state, [""]), 0)
 }
 
-output "key_name" {
-  description = "List of key names of instances"
-  value       = aws_instance.this.*.key_name
+output "outpost_arn" {
+  description = "The ARN of the Outpost the instance is assigned to"
+  value       = element(concat(aws_instance.this.*.outpost_arn, [""]), 0)
 }
 
 output "password_data" {
-  description = "List of Base-64 encoded encrypted password data for the instance"
-  value       = aws_instance.this.*.password_data
-}
-
-output "public_dns" {
-  description = "List of public DNS names assigned to the instances. For EC2-VPC, this is only available if you've enabled DNS hostnames for your VPC"
-  value       = aws_instance.this.*.public_dns
-}
-
-output "public_ip" {
-  description = "List of public IP addresses assigned to the instances, if applicable"
-  value       = aws_instance.this.*.public_ip
-}
-
-output "ipv6_addresses" {
-  description = "List of assigned IPv6 addresses of instances"
-  value       = aws_instance.this.*.ipv6_addresses
+  description = "Base-64 encoded encrypted password data for the instance. Useful for getting the administrator password for instances running Microsoft Windows. This attribute is only exported if `get_password_data` is true"
+  value       = element(concat(aws_instance.this.*.password_data, [""]), 0)
 }
 
 output "primary_network_interface_id" {
-  description = "List of IDs of the primary network interface of instances"
-  value       = aws_instance.this.*.primary_network_interface_id
+  description = "The ID of the instance's primary network interface"
+  value       = element(concat(aws_instance.this.*.primary_network_interface_id, [""]), 0)
 }
 
 output "private_dns" {
-  description = "List of private DNS names assigned to the instances. Can only be used inside the Amazon EC2, and only available if you've enabled DNS hostnames for your VPC"
-  value       = aws_instance.this.*.private_dns
-}
-
-output "private_ip" {
-  description = "List of private IP addresses assigned to the instances"
-  value       = aws_instance.this.*.private_ip
-}
-
-output "security_groups" {
-  description = "List of associated security groups of instances"
-  value       = aws_instance.this.*.security_groups
-}
-
-output "vpc_security_group_ids" {
-  description = "List of associated security groups of instances, if running in non-default VPC"
-  value       = aws_instance.this.*.vpc_security_group_ids
+  description = "The private DNS name assigned to the instance. Can only be used inside the Amazon EC2, and only available if you've enabled DNS hostnames for your VPC"
+  value       = element(concat(aws_instance.this.*.private_dns, [""]), 0)
 }
 
-output "subnet_id" {
-  description = "List of IDs of VPC subnets of instances"
-  value       = aws_instance.this.*.subnet_id
-}
-
-output "credit_specification" {
-  description = "List of credit specification of instances"
-  value       = aws_instance.this.*.credit_specification
-}
-
-output "metadata_options" {
-  description = "List of metadata options of instances"
-  value       = aws_instance.this.*.metadata_options
-}
-
-output "instance_state" {
-  description = "List of instance states of instances"
-  value       = aws_instance.this.*.instance_state
-}
-
-output "root_block_device_volume_ids" {
-  description = "List of volume IDs of root block devices of instances"
-  value       = [for device in aws_instance.this.*.root_block_device : device.*.volume_id]
-}
-
-output "ebs_block_device_volume_ids" {
-  description = "List of volume IDs of EBS block devices of instances"
-  value       = [for device in aws_instance.this.*.ebs_block_device : device.*.volume_id]
-}
-
-output "tags" {
-  description = "List of tags of instances"
-  value       = aws_instance.this.*.tags
+output "public_dns" {
+  description = "The public DNS name assigned to the instance. For EC2-VPC, this is only available if you've enabled DNS hostnames for your VPC"
+  value       = element(concat(aws_instance.this.*.public_dns, [""]), 0)
 }
 
-output "volume_tags" {
-  description = "List of tags of volumes of instances"
-  value       = aws_instance.this.*.volume_tags
+output "public_ip" {
+  description = "The public IP address assigned to the instance, if applicable. NOTE: If you are using an aws_eip with your instance, you should refer to the EIP's address directly and not use `public_ip` as this field will change after the EIP is attached"
+  value       = element(concat(aws_instance.this.*.public_ip, [""]), 0)
 }
 
-output "instance_count" {
-  description = "Number of instances to launch specified as argument to this module"
-  value       = var.instance_count
+output "tags_all" {
+  description = "A map of tags assigned to the resource, including those inherited from the provider default_tags configuration block"
+  value       = element(concat(aws_instance.this.*.tags_all, [""]), 0)
 }

variables.tf

-variable "name" {
-  description = "Name to be used on all resources as prefix"
-  type        = string
+variable "create" {
+  description = "Whether to create an instance"
+  type        = bool
+  default     = true
 }
 
-variable "instance_count" {
-  description = "Number of instances to launch"
-  type        = number
-  default     = 1
+variable "name" {
+  description = "Name to be used on EC2 instance created"
+  type        = string
+  default     = ""
 }
 
 variable "ami" {
   description = "ID of AMI to use for the instance"
   type        = string
-}
-
-variable "placement_group" {
-  description = "The Placement Group to start the instance in"
-  type        = string
   default     = ""
 }
 
-variable "get_password_data" {
-  description = "If true, wait for password data to become available and retrieve it."
+variable "associate_public_ip_address" {
+  description = "Whether to associate a public IP address with an instance in a VPC"
   type        = bool
-  default     = false
+  default     = null
 }
 
-variable "tenancy" {
-  description = "The tenancy of the instance (if the instance is running in a VPC). Available values: default, dedicated, host."
+variable "availability_zone" {
+  description = "AZ to start the instance in"
   type        = string
-  default     = "default"
-}
-
-variable "ebs_optimized" {
-  description = "If true, the launched EC2 instance will be EBS-optimized"
-  type        = bool
-  default     = false
+  default     = null
 }
 
-variable "disable_api_termination" {
-  description = "If true, enables EC2 Instance Termination Protection"
-  type        = bool
-  default     = false
+variable "capacity_reservation_specification" {
+  description = "Describes an instance's Capacity Reservation targeting option"
+  type        = any
+  default     = null
 }
 
-variable "instance_initiated_shutdown_behavior" {
-  description = "Shutdown behavior for the instance" # https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/terminating-instances.html#Using_ChangingInstanceInitiatedShutdownBehavior
+variable "cpu_credits" {
+  description = "The credit option for CPU usage (unlimited or standard)"
   type        = string
-  default     = ""
+  default     = null
 }
 
-variable "instance_type" {
-  description = "The type of instance to start"
-  type        = string
+variable "disable_api_termination" {
+  description = "If true, enables EC2 Instance Termination Protection"
+  type        = bool
+  default     = null
 }
 
-variable "key_name" {
-  description = "The key name to use for the instance"
-  type        = string
-  default     = ""
+variable "ebs_block_device" {
+  description = "Additional EBS block devices to attach to the instance"
+  type        = list(map(string))
+  default     = []
 }
 
-variable "monitoring" {
-  description = "If true, the launched EC2 instance will have detailed monitoring enabled"
+variable "ebs_optimized" {
+  description = "If true, the launched EC2 instance will be EBS-optimized"
   type        = bool
-  default     = false
-}
-
-variable "vpc_security_group_ids" {
-  description = "A list of security group IDs to associate with"
-  type        = list(string)
   default     = null
 }
 
-variable "subnet_id" {
-  description = "The VPC Subnet ID to launch in"
-  type        = string
-  default     = ""
+variable "enclave_options_enabled" {
+  description = "Whether Nitro Enclaves will be enabled on the instance. Defaults to `false`"
+  type        = bool
+  default     = null
 }
 
-variable "subnet_ids" {
-  description = "A list of VPC Subnet IDs to launch in"
-  type        = list(string)
+variable "ephemeral_block_device" {
+  description = "Customize Ephemeral (also known as Instance Store) volumes on the instance"
+  type        = list(map(string))
   default     = []
 }
 
-variable "associate_public_ip_address" {
-  description = "If true, the EC2 instance will have associated public IP address"
+variable "get_password_data" {
+  description = "If true, wait for password data to become available and retrieve it."
   type        = bool
   default     = null
 }
 
-variable "private_ip" {
-  description = "Private IP address to associate with the instance in a VPC"
-  type        = string
+variable "hibernation" {
+  description = "If true, the launched EC2 instance will support hibernation"
+  type        = bool
   default     = null
 }
 
-variable "private_ips" {
-  description = "A list of private IP address to associate with the instance in a VPC. Should match the number of instances."
-  type        = list(string)
-  default     = []
-}
-
-variable "source_dest_check" {
-  description = "Controls if traffic is routed to the instance when the destination address does not match the instance. Used for NAT or VPNs."
-  type        = bool
-  default     = true
+variable "host_id" {
+  description = "ID of a dedicated host that the instance will be assigned to. Use when an instance is to be launched on a specific dedicated host"
+  type        = string
+  default     = null
 }
 
-variable "user_data" {
-  description = "The user data to provide when launching the instance. Do not pass gzip-compressed data via this argument; see user_data_base64 instead."
+variable "iam_instance_profile" {
+  description = "IAM Instance Profile to launch the instance with. Specified as the name of the Instance Profile"
   type        = string
   default     = null
 }
 
-variable "user_data_base64" {
-  description = "Can be used instead of user_data to pass base64-encoded binary data directly. Use this instead of user_data whenever the value is not a valid UTF-8 string. For example, gzip-encoded user data must be base64-encoded and passed via this argument to avoid corruption."
+variable "instance_initiated_shutdown_behavior" {
+  description = "Shutdown behavior for the instance. Amazon defaults this to stop for EBS-backed instances and terminate for instance-store instances. Cannot be set on instance-store instance" # https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/terminating-instances.html#Using_ChangingInstanceInitiatedShutdownBehavior
   type        = string
   default     = null
 }
 
-variable "iam_instance_profile" {
-  description = "The IAM Instance Profile to launch the instance with. Specified as the name of the Instance Profile."
+variable "instance_type" {
+  description = "The type of instance to start"
   type        = string
-  default     = ""
+  default     = "t3.micro"
 }
 
 variable "ipv6_address_count" {
-  description = "A number of IPv6 addresses to associate with the primary network interface. Amazon EC2 chooses the IPv6 addresses from the range of your subnet."
+  description = "A number of IPv6 addresses to associate with the primary network interface. Amazon EC2 chooses the IPv6 addresses from the range of your subnet"
   type        = number
   default     = null
 }
@@ -139,22 +118,46 @@ variable "ipv6_addresses" {
   default     = null
 }
 
-variable "tags" {
-  description = "A mapping of tags to assign to the resource"
+variable "key_name" {
+  description = "Key name of the Key Pair to use for the instance; which can be managed using the `aws_key_pair` resource"
+  type        = string
+  default     = null
+}
+
+variable "launch_template" {
+  description = "Specifies a Launch Template to configure the instance. Parameters configured on this resource will override the corresponding parameters in the Launch Template"
+  type        = map(string)
+  default     = null
+}
+
+variable "metadata_options" {
+  description = "Customize the metadata options of the instance"
   type        = map(string)
   default     = {}
 }
 
-variable "enable_volume_tags" {
-  description = "Whether to enable volume tags (if enabled it conflicts with root_block_device tags)"
+variable "monitoring" {
+  description = "If true, the launched EC2 instance will have detailed monitoring enabled"
   type        = bool
-  default     = true
+  default     = false
 }
 
-variable "volume_tags" {
-  description = "A mapping of tags to assign to the devices created by the instance at launch time"
-  type        = map(string)
-  default     = {}
+variable "network_interface" {
+  description = "Customize network interfaces to be attached at instance boot time"
+  type        = list(map(string))
+  default     = []
+}
+
+variable "placement_group" {
+  description = "The Placement Group to start the instance in"
+  type        = string
+  default     = null
+}
+
+variable "private_ip" {
+  description = "Private IP address to associate with the instance in a VPC"
+  type        = string
+  default     = null
 }
 
 variable "root_block_device" {
@@ -163,46 +166,70 @@ variable "root_block_device" {
   default     = []
 }
 
-variable "ebs_block_device" {
-  description = "Additional EBS block devices to attach to the instance"
-  type        = list(map(string))
-  default     = []
+variable "secondary_private_ips" {
+  description = "A list of secondary private IPv4 addresses to assign to the instance's primary network interface (eth0) in a VPC. Can only be assigned to the primary network interface (eth0) attached at instance creation, not a pre-existing network interface i.e. referenced in a `network_interface block`"
+  type        = list(string)
+  default     = null
 }
 
-variable "ephemeral_block_device" {
-  description = "Customize Ephemeral (also known as Instance Store) volumes on the instance"
-  type        = list(map(string))
-  default     = []
+variable "source_dest_check" {
+  description = "Controls if traffic is routed to the instance when the destination address does not match the instance. Used for NAT or VPNs."
+  type        = bool
+  default     = true
 }
 
-variable "network_interface" {
-  description = "Customize network interfaces to be attached at instance boot time"
-  type        = list(map(string))
-  default     = []
+variable "subnet_id" {
+  description = "The VPC Subnet ID to launch in"
+  type        = string
+  default     = null
 }
 
-variable "cpu_credits" {
-  description = "The credit option for CPU usage (unlimited or standard)"
+variable "tags" {
+  description = "A mapping of tags to assign to the resource"
+  type        = map(string)
+  default     = {}
+}
+
+variable "tenancy" {
+  description = "The tenancy of the instance (if the instance is running in a VPC). Available values: default, dedicated, host."
   type        = string
-  default     = "standard"
+  default     = null
 }
 
-variable "metadata_options" {
-  description = "Customize the metadata options of the instance"
+variable "user_data" {
+  description = "The user data to provide when launching the instance. Do not pass gzip-compressed data via this argument; see user_data_base64 instead."
+  type        = string
+  default     = null
+}
+
+variable "user_data_base64" {
+  description = "Can be used instead of user_data to pass base64-encoded binary data directly. Use this instead of user_data whenever the value is not a valid UTF-8 string. For example, gzip-encoded user data must be base64-encoded and passed via this argument to avoid corruption."
+  type        = string
+  default     = null
+}
+
+variable "volume_tags" {
+  description = "A mapping of tags to assign to the devices created by the instance at launch time"
   type        = map(string)
   default     = {}
 }
 
-variable "use_num_suffix" {
-  description = "Always append numerical suffix to instance name, even if instance_count is 1"
+variable "enable_volume_tags" {
+  description = "Whether to enable volume tags (if enabled it conflicts with root_block_device tags)"
   type        = bool
-  default     = false
+  default     = true
 }
 
-variable "num_suffix_format" {
-  description = "Numerical suffix format used as the volume and EC2 instance name suffix"
-  type        = string
-  default     = "-%d"
+variable "vpc_security_group_ids" {
+  description = "A list of security group IDs to associate with"
+  type        = list(string)
+  default     = null
+}
+
+variable "timeouts" {
+  description = "Define maximum timeout for creating, updating, and deleting EC2 instance resources"
+  type        = map(string)
+  default     = {}
 }
 
 variable "cpu_core_count" {

versions.tf

 terraform {
-  required_version = ">= 0.12.6"
+  required_version = ">= 0.13.1"
 
   required_providers {
-    aws = ">= 3.24"
+    aws = {
+      source  = "hashicorp/aws"
+      version = ">= 3.51"
+    }
   }
 }