Issue when using Terraform to manage credentials that access RDS database - amazon-web-services

Question

I created a secret via Terraform, the secret is for accessing an RDS database which is also defined in Terraform, and in the secret, I don't want to include username and password, so I created an empty secret then add the credentials manually in AWS console.
Then in the RDS definition:
resource "aws_rds_cluster" "example_db_cluster" {
cluster_identifier = local.db_name
engine = "aurora-mysql"
engine_version = "xxx"
engine_mode = "xxx"
availability_zones = [xxx]
database_name = "xxx"
master_username = jsondecode(aws_secretsmanager_secret_version.db_secret_string.secret_string)["username"]
master_password = jsondecode(aws_secretsmanager_secret_version.db_secret_string.secret_string)["password"]
.....
The problem is that when I apply terraform, because the secret is empty so Terraform won't find the string for username and password which will cause error, does anyone have a better way to implement this? Feels like it's easier to just create the secret in Secret Manager manually.

Answer 1

You can generate a random_password and add to your secret using a aws_secretsmanager_secret_version.
Here's an example:
resource "random_password" "default_password" {
length = 20
special = false
}
variable "secretString" {
default = {
usernae = "dbuser"
password = random_password.default_password.result
}
type = map(string)
}
resource "aws_secretsmanager_secret" "db_secret_string" {
name = "db_secret_string"
}
resource "aws_secretsmanager_secret_version" "secret" {
secret_id = aws_secretsmanager_secret.db_secret_string.id
secret_string = jsonencode(var.secretString)
}