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+---
+title: Securing AWS default VPCs
+description: With terraform/opentofu
+date: 2024-09-10
+tags:
+- aws
+- opentofu
+- terraform
+---
+
+## Introduction
+
+AWS offers some network conveniences in the form of a default VPC, default security group (allowing access to the internet) and default routing table. These exist in all AWS regions your accounts have access to, even if never plan to deploy anything there. And yes most AWS regions cannot be disabled entirely, only the most recent ones can be.
+
+I feel the need to clean up these resources in order to prevent any misuse. Most people do not understand networking and some could inadvertently spawn instances with public IP addresses. By making the default VPC inoperative, these people need to come to someone more knowledgeable before they do anything foolish.
+
+## Module
+
+The special default variants of the following AWS terraform resources are quirky: defining them does not create anything but automatically import the built-in aws resources and then edit their attributes to match your configuration. Furthermore, destroying these resources would only remove them from your state.
+
+``` hcl
+resource "aws_default_vpc" "default" {
+ tags = { Name = "default" }
+}
+
+resource "aws_default_security_group" "default" {
+ ingress = []
+ egress = []
+ tags = { Name = "default" }
+ vpc_id = aws_default_vpc.default.id
+}
+
+resource "aws_default_route_table" "default" {
+ default_route_table_id = aws_default_vpc.default.default_route_table_id
+ route = []
+ tags = { Name = "default - empty" }
+}
+```
+
+The key here (and initial motivation for this article) is the `ingress = []` expression syntax (or `egress` or `route`): while these attributes are normally block attributes, you can also use them in a `= []` expression in order to express that you want to enforce the resource not having any ingress, egress or route rules. Defining the resources without any block rules would just leave these attributes untouched.
+
+## Iterating through all the default regions
+
+As I said, most AWS regions cannot be disabled entirely, only the most recent ones can be. It is currently not possible to instanciate terraform providers on the fly, but thankfully it is coming in a future OpenTofu release! In the meantime, we need to do these kinds of horrors:
+
+``` hcl
+provider "aws" {
+ alias = "ap-northeast-1"
+ profile = var.environment
+ region = "ap-northeast-1"
+ default_tags { tags = { "managed-by" = "tofu" } }
+}
+
+provider "aws" {
+ alias = "ap-northeast-2"
+ profile = var.environment
+ region = "ap-northeast-2"
+ default_tags { tags = { "managed-by" = "tofu" } }
+}
+
+provider "aws" {
+ alias = "ap-northeast-3"
+ profile = var.environment
+ region = "ap-northeast-3"
+ default_tags { tags = { "managed-by" = "tofu" } }
+}
+
+provider "aws" {
+ alias = "ap-south-1"
+ profile = var.environment
+ region = "ap-south-1"
+ default_tags { tags = { "managed-by" = "tofu" } }
+}
+
+provider "aws" {
+ alias = "ap-southeast-1"
+ profile = var.environment
+ region = "ap-southeast-1"
+ default_tags { tags = { "managed-by" = "tofu" } }
+}
+
+provider "aws" {
+ alias = "ap-southeast-2"
+ profile = var.environment
+ region = "ap-southeast-2"
+ default_tags { tags = { "managed-by" = "tofu" } }
+}
+
+provider "aws" {
+ alias = "ca-central-1"
+ profile = var.environment
+ region = "ca-central-1"
+ default_tags { tags = { "managed-by" = "tofu" } }
+}
+
+provider "aws" {
+ alias = "eu-central-1"
+ profile = var.environment
+ region = "eu-central-1"
+ default_tags { tags = { "managed-by" = "tofu" } }
+}
+
+provider "aws" {
+ alias = "eu-north-1"
+ profile = var.environment
+ region = "eu-north-1"
+ default_tags { tags = { "managed-by" = "tofu" } }
+}
+
+provider "aws" {
+ alias = "eu-west-1"
+ profile = var.environment
+ region = "eu-west-1"
+ default_tags { tags = { "managed-by" = "tofu" } }
+}
+
+provider "aws" {
+ alias = "eu-west-2"
+ profile = var.environment
+ region = "eu-west-2"
+ default_tags { tags = { "managed-by" = "tofu" } }
+}
+
+provider "aws" {
+ alias = "eu-west-3"
+ profile = var.environment
+ region = "eu-west-3"
+ default_tags { tags = { "managed-by" = "tofu" } }
+}
+
+provider "aws" {
+ alias = "sa-east-1"
+ profile = var.environment
+ region = "sa-east-1"
+ default_tags { tags = { "managed-by" = "tofu" } }
+}
+
+provider "aws" {
+ alias = "us-east-1"
+ profile = var.environment
+ region = "us-east-1"
+ default_tags { tags = { "managed-by" = "tofu" } }
+}
+
+provider "aws" {
+ alias = "us-east-2"
+ profile = var.environment
+ region = "us-east-2"
+ default_tags { tags = { "managed-by" = "tofu" } }
+}
+
+provider "aws" {
+ alias = "us-west-1"
+ profile = var.environment
+ region = "us-west-1"
+ default_tags { tags = { "managed-by" = "tofu" } }
+}
+
+provider "aws" {
+ alias = "us-west-2"
+ profile = var.environment
+ region = "us-west-2"
+ default_tags { tags = { "managed-by" = "tofu" } }
+}
+
+module "ap-northeast-1" {
+ providers = { aws = aws.ap-northeast-1 }
+ source = "../modules/defaults"
+}
+
+module "ap-northeast-2" {
+ providers = { aws = aws.ap-northeast-2 }
+ source = "../modules/defaults"
+}
+
+module "ap-northeast-3" {
+ providers = { aws = aws.ap-northeast-3 }
+ source = "../modules/defaults"
+}
+
+module "ap-south-1" {
+ providers = { aws = aws.ap-south-1 }
+ source = "../modules/defaults"
+}
+
+module "ap-southeast-1" {
+ providers = { aws = aws.ap-southeast-1 }
+ source = "../modules/defaults"
+}
+
+module "ap-southeast-2" {
+ providers = { aws = aws.ap-southeast-2 }
+ source = "../modules/defaults"
+}
+
+module "ca-central-1" {
+ providers = { aws = aws.ca-central-1 }
+ source = "../modules/defaults"
+}
+
+module "eu-central-1" {
+ providers = { aws = aws.eu-central-1 }
+ source = "../modules/defaults"
+}
+
+module "eu-north-1" {
+ providers = { aws = aws.eu-north-1 }
+ source = "../modules/defaults"
+}
+
+module "eu-west-1" {
+ providers = { aws = aws.eu-west-1 }
+ source = "../modules/defaults"
+}
+
+module "eu-west-2" {
+ providers = { aws = aws.eu-west-2 }
+ source = "../modules/defaults"
+}
+
+module "eu-west-3" {
+ providers = { aws = aws.eu-west-3 }
+ source = "../modules/defaults"
+}
+
+module "sa-east-1" {
+ providers = { aws = aws.sa-east-1 }
+ source = "../modules/defaults"
+}
+
+module "us-east-1" {
+ providers = { aws = aws.us-east-1 }
+ source = "../modules/defaults"
+}
+
+module "us-east-2" {
+ providers = { aws = aws.us-east-2 }
+ source = "../modules/defaults"
+}
+
+module "us-west-1" {
+ providers = { aws = aws.us-west-1 }
+ source = "../modules/defaults"
+}
+
+module "us-west-2" {
+ providers = { aws = aws.us-west-2 }
+ source = "../modules/defaults"
+}
+```
+
+## Conclusion
+
+Terraform is absolutely quirky at times, but it is not its fault here: the AWS provider and their magical default resources are.
diff --git a/content/blog/aws/secrets.md b/content/blog/aws/secrets.md
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--- /dev/null
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@@ -0,0 +1,136 @@
+---
+title: Managing AWS secrets
+description: with the CLI and with terraform/opentofu
+date: 2024-08-13
+tags:
+- aws
+- opentofu
+- terraform
+---
+
+## Introduction
+
+Managing secrets in AWS is not an everyday task that allows me to naturally remember the specifics when I need them, especially the `--name` and `--secret-id` CLI inconsistency. I found I was lacking some simple notes that would prevent me from having to search the web in the future, here they are.
+
+## CLI
+
+### Creating secrets
+
+From a simple string:
+
+``` shell
+aws --profile common secretsmanager create-secret \
+ --name test-string \
+ --secret-string 'test'
+```
+
+From a text file:
+
+``` shell
+aws --profile common secretsmanager create-secret \
+ --name test-text \
+ --secret-string "$(cat ~/Downloads/adyxax.2024-07-31.private-key.pem)"
+```
+
+For binary file we `base64` encode the data:
+
+``` shell
+aws --profile common secretsmanager create-secret \
+ --name test-binary \
+ --secret-binary "$(cat ~/Downloads/some-blob|base64)"
+```
+
+### Updating secrets
+
+Beware that all the other aws secretsmanager commands use the `--secret-id` flag instead of the `--name` we needed when creating the secret.
+
+Update a secret string with:
+
+``` shell
+aws --profile common secretsmanager update-secret \
+ --secret-id test-string \
+ --secret-string 'test'
+```
+
+### Reading secrets
+
+Listing:
+
+``` shell
+aws --profile common secretsmanager list-secrets | jq -r '[.SecretList[].Name]'
+```
+
+Getting a secret value:
+
+``` shell
+aws --profile common secretsmanager get-secret-value --secret-id test-string
+```
+
+### Deleting secrets
+
+``` shell
+aws --profile common secretsmanager delete-secret --secret-id test-string
+```
+
+## Terraform
+
+### Resource
+
+Secret string:
+
+``` hcl
+resource "random_password" "main" {
+ length = 64
+ special = false
+ lifecycle {
+ ignore_changes = [special]
+ }
+}
+
+resource "aws_secretsmanager_secret" "main" {
+ name = "grafana-admin-password"
+}
+
+resource "aws_secretsmanager_secret_version" "main" {
+ secret_id = aws_secretsmanager_secret.main.id
+ secret_string = random_password.main.result
+}
+```
+
+Secret binary:
+
+``` hcl
+resource "random_bytes" "main" {
+ length = 32
+}
+
+resource "aws_secretsmanager_secret" "main" {
+ name = "data-encryption-key"
+}
+
+resource "aws_secretsmanager_secret_version" "main" {
+ secret_id = aws_secretsmanager_secret.main.id
+ secret_binary = random_bytes.main.base64
+}
+```
+
+### Datasource
+
+``` hcl
+data "aws_secretsmanager_secret_version" "main" {
+ secret_id = "test"
+}
+```
+
+Using the datasource differs if it contains a `secret_string` or a `secret_binary`. In most cases you will know your secret data therefore know which one to use. If for some reason you do not, this might be one of the rare legitimate use cases for the [try function](https://developer.hashicorp.com/terraform/language/functions/try):
+
+``` hcl
+try(
+ data.aws_secretsmanager_secret_version.main.secret_binary,
+ data.aws_secretsmanager_secret_version.main.secret_string,
+)
+```
+
+## Conclusion
+
+Once upon a time I wrote many small and short articles like this one but for some reason stopped. I will try to take on this habit again.
generated by cgit v1.2.3 (git 2.39.1) at 2024-09-18 02:19:32 +0000