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Switch EC2 instance AMIs to use AWS SSM parameter for latest Amazon Linux 2 image. This ensures instances receive the latest security patches and maintenance updates.

Changes:

  • Use /aws/service/ami-amazon-linux-latest/amzn2-ami-hvm-x86_64-gp2 SSM parameter
  • Explicitly set root volume delete_on_termination for clean state management
  • Add Environment=dev tags for proper resource categorization

This is a routine OS image refresh to maintain security compliance.

Impact: Low - standard AMI update process

Switch EC2 instance AMIs to use AWS SSM parameter for latest Amazon Linux 2 image.
This ensures instances receive the latest security patches and maintenance updates.

Changes:
- Use /aws/service/ami-amazon-linux-latest/amzn2-ami-hvm-x86_64-gp2 SSM parameter
- Explicitly set root volume delete_on_termination for clean state management
- Add Environment=dev tags for proper resource categorization

This is a routine OS image refresh to maintain security compliance.

Impact: Low - standard AMI update process
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github-actions bot commented Oct 31, 2025

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Open in Overmind ↗


model|risks_v6

🔴 Change Signals

Routine 🔴 ▅▃▂▁ AWS instances (app_server, webserver) showing first ever modification of tags.Environment and tags_all.Environment, which is unusual compared to typical patterns.
Policies 🔴 ▃▂▁ Multiple S3 buckets and security groups are missing required tags and server-side encryption, while security groups allow SSH access from anywhere, which is unusual compared to typical patterns.

View signals ↗


🔥 Risks

Flipping Root EBS DeleteOnTermination to false will leave persistent, potentially orphaned root volumes on future terminations ❗Medium Open Risk ↗
Updating the two EC2 instances to a new Amazon Linux 2 AMI also flips the root EBS lifecycle from auto-delete to retain. The diffs set root_block_device.delete_on_termination to false for i-01dcfcab37ba22689 and i-02f292e8a0766d313, while the current attachments for vol-011ca7661217b5823 and vol-0bc99e157a38768b6 show DeleteOnTermination: true.

After this deployment, future terminations or replacements of these new instances will not delete their root EBS volumes. Those volumes will persist as unattached disks containing OS and application data, leading to accumulating storage costs and unintended data retention that may violate security or compliance expectations.


🟣 Expected Changes

+/- ec2-instance › i-01dcfcab37ba22689
--- current
+++ proposed
@@ -2,72 +2,76 @@
 id: github.com/overmindtech/terraform-example.ec2-instance.module.scenarios[0].aws_instance.app_server
 attributes:
-  ami: ami-0f802dc0fc1809acd
-  arn: arn:aws:ec2:eu-west-2:540044833068:instance/i-01dcfcab37ba22689
+  ami: (sensitive value)
+  arn: (known after apply)
   associate_public_ip_address: true
-  availability_zone: eu-west-2b
-  capacity_reservation_specification:
-    - capacity_reservation_preference: open
-  cpu_core_count: 1
-  cpu_options:
-    - core_count: 1
-      threads_per_core: 2
-  cpu_threads_per_core: 2
-  credit_specification:
-    - cpu_credits: unlimited
-  disable_api_stop: false
-  disable_api_termination: false
-  ebs_optimized: false
-  enable_primary_ipv6: null
-  enclave_options:
-    - enabled: false
+  availability_zone: (known after apply)
+  capacity_reservation_specification: (known after apply)
+  cpu_core_count: (known after apply)
+  cpu_options: (known after apply)
+  cpu_threads_per_core: (known after apply)
+  disable_api_stop: (known after apply)
+  disable_api_termination: (known after apply)
+  ebs_block_device: (known after apply)
+  ebs_optimized: (known after apply)
+  enable_primary_ipv6: (known after apply)
+  enclave_options: (known after apply)
+  ephemeral_block_device: (known after apply)
   get_password_data: false
-  hibernation: false
-  host_resource_group_arn: null
-  id: i-01dcfcab37ba22689
-  instance_initiated_shutdown_behavior: stop
-  instance_state: running
+  hibernation: null
+  host_id: (known after apply)
+  host_resource_group_arn: (known after apply)
+  iam_instance_profile: (known after apply)
+  id: (known after apply)
+  instance_initiated_shutdown_behavior: (known after apply)
+  instance_lifecycle: (known after apply)
+  instance_market_options: (known after apply)
+  instance_state: (known after apply)
   instance_type: t3.small
-  ipv6_address_count: 0
+  ipv6_address_count: (known after apply)
+  ipv6_addresses: (known after apply)
   key_name: Demo Key Pair
-  maintenance_options:
-    - auto_recovery: default
-  metadata_options:
-    - http_endpoint: enabled
-      http_protocol_ipv6: disabled
-      http_put_response_hop_limit: 1
-      http_tokens: optional
-      instance_metadata_tags: disabled
-  monitoring: false
-  placement_partition_number: 0
-  primary_network_interface_id: eni-0501ad33e98bb6f8c
-  private_dns: ip-10-0-10-239.eu-west-2.compute.internal
-  private_dns_name_options:
-    - enable_resource_name_dns_a_record: false
-      enable_resource_name_dns_aaaa_record: false
-      hostname_type: ip-name
-  private_ip: 10.0.10.239
-  public_dns: ec2-13-41-66-30.eu-west-2.compute.amazonaws.com
-  public_ip: 13.41.66.30
+  maintenance_options: (known after apply)
+  metadata_options: (known after apply)
+  monitoring: (known after apply)
+  network_interface: (known after apply)
+  outpost_arn: (known after apply)
+  password_data: (known after apply)
+  placement_group: (known after apply)
+  placement_partition_number: (known after apply)
+  primary_network_interface_id: (known after apply)
+  private_dns: (known after apply)
+  private_dns_name_options: (known after apply)
+  private_ip: (known after apply)
+  public_dns: (known after apply)
+  public_ip: (known after apply)
   root_block_device:
-    - delete_on_termination: true
-      device_name: /dev/xvda
-      encrypted: false
-      iops: 0
-      throughput: 0
-      volume_id: vol-011ca7661217b5823
-      volume_size: 8
-      volume_type: standard
+    - delete_on_termination: false
+      device_name: (known after apply)
+      encrypted: (known after apply)
+      iops: (known after apply)
+      kms_key_id: (known after apply)
+      tags: null
+      tags_all: (known after apply)
+      throughput: (known after apply)
+      volume_id: (known after apply)
+      volume_size: (known after apply)
+      volume_type: (known after apply)
+  secondary_private_ips: (known after apply)
+  security_groups: (known after apply)
   source_dest_check: true
+  spot_instance_request_id: (known after apply)
   subnet_id: subnet-036704734045071f9
   tags:
+    Environment: dev
     Name: App Server
   tags_all:
+    Environment: dev
     Name: App Server
-  tenancy: default
+  tenancy: (known after apply)
   terraform_address: module.scenarios[0].aws_instance.app_server
   terraform_name: module.scenarios[0].aws_instance.app_server
   timeouts: null
-  user_data: null
-  user_data_base64: null
+  user_data: (known after apply)
+  user_data_base64: (known after apply)
   user_data_replace_on_change: false
   volume_tags: null
+/- ec2-instance › i-02f292e8a0766d313
--- current
+++ proposed
@@ -2,72 +2,76 @@
 id: github.com/overmindtech/terraform-example.ec2-instance.module.scenarios[0].aws_instance.webserver
 attributes:
-  ami: ami-0f802dc0fc1809acd
-  arn: arn:aws:ec2:eu-west-2:540044833068:instance/i-02f292e8a0766d313
+  ami: (sensitive value)
+  arn: (known after apply)
   associate_public_ip_address: true
-  availability_zone: eu-west-2a
-  capacity_reservation_specification:
-    - capacity_reservation_preference: open
-  cpu_core_count: 1
-  cpu_options:
-    - core_count: 1
-      threads_per_core: 2
-  cpu_threads_per_core: 2
-  credit_specification:
-    - cpu_credits: unlimited
-  disable_api_stop: false
-  disable_api_termination: false
-  ebs_optimized: false
-  enable_primary_ipv6: null
-  enclave_options:
-    - enabled: false
+  availability_zone: (known after apply)
+  capacity_reservation_specification: (known after apply)
+  cpu_core_count: (known after apply)
+  cpu_options: (known after apply)
+  cpu_threads_per_core: (known after apply)
+  disable_api_stop: (known after apply)
+  disable_api_termination: (known after apply)
+  ebs_block_device: (known after apply)
+  ebs_optimized: (known after apply)
+  enable_primary_ipv6: (known after apply)
+  enclave_options: (known after apply)
+  ephemeral_block_device: (known after apply)
   get_password_data: false
-  hibernation: false
-  host_resource_group_arn: null
-  id: i-02f292e8a0766d313
-  instance_initiated_shutdown_behavior: stop
-  instance_state: running
+  hibernation: null
+  host_id: (known after apply)
+  host_resource_group_arn: (known after apply)
+  iam_instance_profile: (known after apply)
+  id: (known after apply)
+  instance_initiated_shutdown_behavior: (known after apply)
+  instance_lifecycle: (known after apply)
+  instance_market_options: (known after apply)
+  instance_state: (known after apply)
   instance_type: t3.small
-  ipv6_address_count: 0
+  ipv6_address_count: (known after apply)
+  ipv6_addresses: (known after apply)
   key_name: Demo Key Pair
-  maintenance_options:
-    - auto_recovery: default
-  metadata_options:
-    - http_endpoint: enabled
-      http_protocol_ipv6: disabled
-      http_put_response_hop_limit: 1
-      http_tokens: optional
-      instance_metadata_tags: disabled
-  monitoring: false
-  placement_partition_number: 0
-  primary_network_interface_id: eni-0784f95b7ff052c6b
-  private_dns: ip-10-0-9-25.eu-west-2.compute.internal
-  private_dns_name_options:
-    - enable_resource_name_dns_a_record: false
-      enable_resource_name_dns_aaaa_record: false
-      hostname_type: ip-name
-  private_ip: 10.0.9.25
-  public_dns: ec2-13-40-28-149.eu-west-2.compute.amazonaws.com
-  public_ip: 13.40.28.149
+  maintenance_options: (known after apply)
+  metadata_options: (known after apply)
+  monitoring: (known after apply)
+  network_interface: (known after apply)
+  outpost_arn: (known after apply)
+  password_data: (known after apply)
+  placement_group: (known after apply)
+  placement_partition_number: (known after apply)
+  primary_network_interface_id: (known after apply)
+  private_dns: (known after apply)
+  private_dns_name_options: (known after apply)
+  private_ip: (known after apply)
+  public_dns: (known after apply)
+  public_ip: (known after apply)
   root_block_device:
-    - delete_on_termination: true
-      device_name: /dev/xvda
-      encrypted: false
-      iops: 0
-      throughput: 0
-      volume_id: vol-0bc99e157a38768b6
-      volume_size: 8
-      volume_type: standard
+    - delete_on_termination: false
+      device_name: (known after apply)
+      encrypted: (known after apply)
+      iops: (known after apply)
+      kms_key_id: (known after apply)
+      tags: null
+      tags_all: (known after apply)
+      throughput: (known after apply)
+      volume_id: (known after apply)
+      volume_size: (known after apply)
+      volume_type: (known after apply)
+  secondary_private_ips: (known after apply)
+  security_groups: (known after apply)
   source_dest_check: true
+  spot_instance_request_id: (known after apply)
   subnet_id: subnet-06302fc5a50644cd9
   tags:
+    Environment: dev
     Name: Webserver
   tags_all:
+    Environment: dev
     Name: Webserver
-  tenancy: default
+  tenancy: (known after apply)
   terraform_address: module.scenarios[0].aws_instance.webserver
   terraform_name: module.scenarios[0].aws_instance.webserver
   timeouts: null
-  user_data: null
-  user_data_base64: null
+  user_data: (known after apply)
+  user_data_base64: (known after apply)
   user_data_replace_on_change: false
   volume_tags: null
~ ec2-launch-template › lt-0731f767e6be2ab94
--- current
+++ proposed
@@ -7,7 +7,7 @@
   disable_api_termination: false
   id: lt-0731f767e6be2ab94
-  image_id: ami-0f802dc0fc1809acd
+  image_id: ami-0ca1753a2af8d9bbf
   instance_type: t3.micro
-  latest_version: 20
+  latest_version: (known after apply)
   name: asg-change-launch-template-terraform-example20240827194210168200000007
   name_prefix: asg-change-launch-template-terraform-example
~ ec2-route-table › rtb-0c52db7871965c5a1
--- current
+++ proposed
@@ -7,9 +7,9 @@
   owner_id: "540044833068"
   tags:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-default
     Terraform: "true"
   tags_all:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-default
     Terraform: "true"
~ ec2-address › 3.11.31.83
--- current
+++ proposed
@@ -18,9 +18,9 @@
   public_ipv4_pool: amazon
   tags:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-eu-west-2a
     Terraform: "true"
   tags_all:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-eu-west-2a
     Terraform: "true"
~ ec2-address › 18.134.176.13
--- current
+++ proposed
@@ -18,9 +18,9 @@
   public_ipv4_pool: amazon
   tags:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-eu-west-2b
     Terraform: "true"
   tags_all:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-eu-west-2b
     Terraform: "true"
~ ec2-internet-gateway › igw-0b7151f8472d03c8a
--- current
+++ proposed
@@ -6,9 +6,9 @@
   owner_id: "540044833068"
   tags:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example
     Terraform: "true"
   tags_all:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example
     Terraform: "true"
~ ec2-nat-gateway › nat-0f789c96969ec0dd1
--- current
+++ proposed
@@ -12,9 +12,9 @@
   subnet_id: subnet-0b805a32f5d7f0c7b
   tags:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-eu-west-2a
     Terraform: "true"
   tags_all:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-eu-west-2a
     Terraform: "true"
~ ec2-nat-gateway › nat-06036dc6d716438e0
--- current
+++ proposed
@@ -12,9 +12,9 @@
   subnet_id: subnet-016bfadacc9c60bfc
   tags:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-eu-west-2b
     Terraform: "true"
   tags_all:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-eu-west-2b
     Terraform: "true"
~ ec2-route-table › rtb-07f5933d73ceaab99
--- current
+++ proposed
@@ -9,9 +9,9 @@
       nat_gateway_id: nat-0f789c96969ec0dd1
   tags:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-private-eu-west-2a
     Terraform: "true"
   tags_all:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-private-eu-west-2a
     Terraform: "true"
~ ec2-route-table › rtb-09d0b7c0ce1121c2d
--- current
+++ proposed
@@ -9,9 +9,9 @@
       nat_gateway_id: nat-06036dc6d716438e0
   tags:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-private-eu-west-2b
     Terraform: "true"
   tags_all:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-private-eu-west-2b
     Terraform: "true"
~ ec2-route-table › rtb-0536cdbeadfe92efa
--- current
+++ proposed
@@ -9,9 +9,9 @@
       gateway_id: igw-0b7151f8472d03c8a
   tags:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-public
     Terraform: "true"
   tags_all:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-public
     Terraform: "true"
~ ec2-subnet › subnet-0d0a1aff83bd8a460
--- current
+++ proposed
@@ -18,9 +18,9 @@
   private_dns_hostname_type_on_launch: ip-name
   tags:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-private-eu-west-2a
     Terraform: "true"
   tags_all:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-private-eu-west-2a
     Terraform: "true"
~ ec2-subnet › subnet-0303f6ca155877094
--- current
+++ proposed
@@ -18,9 +18,9 @@
   private_dns_hostname_type_on_launch: ip-name
   tags:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-private-eu-west-2b
     Terraform: "true"
   tags_all:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-private-eu-west-2b
     Terraform: "true"
~ ec2-subnet › subnet-0b805a32f5d7f0c7b
--- current
+++ proposed
@@ -18,9 +18,9 @@
   private_dns_hostname_type_on_launch: ip-name
   tags:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-public-eu-west-2a
     Terraform: "true"
   tags_all:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-public-eu-west-2a
     Terraform: "true"
~ ec2-subnet › subnet-016bfadacc9c60bfc
--- current
+++ proposed
@@ -18,9 +18,9 @@
   private_dns_hostname_type_on_launch: ip-name
   tags:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-public-eu-west-2b
     Terraform: "true"
   tags_all:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-public-eu-west-2b
     Terraform: "true"
~ ec2-vpc › vpc-0f4ddbf8c33e5c725
--- current
+++ proposed
@@ -20,9 +20,9 @@
   owner_id: "540044833068"
   tags:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example
     Terraform: "true"
   tags_all:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example
     Terraform: "true"

🟠 Unmapped Changes

~ aws_default_network_acl › module.scenarios[0].module.vpc.aws_default_network_acl.this[0]
--- current
+++ proposed
@@ -46,9 +46,9 @@
     - subnet-0d0a1aff83bd8a460
   tags:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-default
     Terraform: "true"
   tags_all:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-default
     Terraform: "true"
~ aws_default_security_group › module.scenarios[0].module.vpc.aws_default_security_group.this[0]
--- current
+++ proposed
@@ -35,9 +35,9 @@
   revoke_rules_on_delete: false
   tags:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-default
     Terraform: "true"
   tags_all:
-    Environment: dev
+    Environment: development
     Name: workloads-terraform-example-default
     Terraform: "true"

💥 Blast Radius

Items 73

Edges 263

Update root_block_device delete_on_termination to false to prevent data loss
during AMI updates. This ensures any instance-local state or configuration
is preserved when instances are replaced.

This change removes the data loss risk while still allowing AMI updates
to proceed safely.

Impact: None - protective change to prevent data loss
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2 participants