feat: Use Instance Metadata Service Version 2 by default. (#3513)

This closes #3512.

Co-authored-by: Niek Palm <npalm@users.noreply.github.com>

README.md

@@ -575,7 +575,7 @@ We welcome any improvement to the standard module to make the default as secure
 | <a name="input_runner_group_name"></a> [runner\_group\_name](#input\_runner\_group\_name) | Name of the runner group. | `string` | `"Default"` | no |
 | <a name="input_runner_iam_role_managed_policy_arns"></a> [runner\_iam\_role\_managed\_policy\_arns](#input\_runner\_iam\_role\_managed\_policy\_arns) | Attach AWS or customer-managed IAM policies (by ARN) to the runner IAM role | `list(string)` | `[]` | no |
 | <a name="input_runner_log_files"></a> [runner\_log\_files](#input\_runner\_log\_files) | (optional) Replaces the module default cloudwatch log config. See https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/CloudWatch-Agent-Configuration-File-Details.html for details. | <pre>list(object({<br>    log_group_name   = string<br>    prefix_log_group = bool<br>    file_path        = string<br>    log_stream_name  = string<br>  }))</pre> | `null` | no |
-| <a name="input_runner_metadata_options"></a> [runner\_metadata\_options](#input\_runner\_metadata\_options) | Metadata options for the ec2 runner instances. By default, the module uses metadata tags for bootstrapping the runner, only disable `instance_metadata_tags` when using custom scripts for starting the runner. | `map(any)` | <pre>{<br>  "http_endpoint": "enabled",<br>  "http_put_response_hop_limit": 1,<br>  "http_tokens": "optional",<br>  "instance_metadata_tags": "enabled"<br>}</pre> | no |
+| <a name="input_runner_metadata_options"></a> [runner\_metadata\_options](#input\_runner\_metadata\_options) | Metadata options for the ec2 runner instances. By default, the module uses metadata tags for bootstrapping the runner, only disable `instance_metadata_tags` when using custom scripts for starting the runner. | `map(any)` | <pre>{<br>  "http_endpoint": "enabled",<br>  "http_put_response_hop_limit": 1,<br>  "http_tokens": "required",<br>  "instance_metadata_tags": "enabled"<br>}</pre> | no |
 | <a name="input_runner_name_prefix"></a> [runner\_name\_prefix](#input\_runner\_name\_prefix) | The prefix used for the GitHub runner name. The prefix will be used in the default start script to prefix the instance name when register the runner in GitHub. The value is availabe via an EC2 tag 'ghr:runner\_name\_prefix'. | `string` | `""` | no |
 | <a name="input_runner_os"></a> [runner\_os](#input\_runner\_os) | The EC2 Operating System type to use for action runner instances (linux,windows). | `string` | `"linux"` | no |
 | <a name="input_runner_run_as"></a> [runner\_run\_as](#input\_runner\_run\_as) | Run the GitHub actions agent as user. | `string` | `"ec2-user"` | no |

modules/multi-runner/variables.tf

@@ -33,7 +33,7 @@ variable "multi_runner_config" {
       runner_metadata_options = optional(map(any), {
         instance_metadata_tags      = "enabled"
         http_endpoint               = "enabled"
-        http_tokens                 = "optional"
+        http_tokens                 = "required"
         http_put_response_hop_limit = 1
       })
       ami_filter                              = optional(map(list(string)), { state = ["available"] })

modules/runners/variables.tf

@@ -504,7 +504,7 @@ variable "metadata_options" {
   default = {
     instance_metadata_tags      = "enabled"
     http_endpoint               = "enabled"
-    http_tokens                 = "optional"
+    http_tokens                 = "required"
     http_put_response_hop_limit = 1
   }
 }

variables.tf

@@ -572,7 +572,7 @@ variable "runner_metadata_options" {
   default = {
     instance_metadata_tags      = "enabled"
     http_endpoint               = "enabled"
-    http_tokens                 = "optional"
+    http_tokens                 = "required"
     http_put_response_hop_limit = 1
   }
 }