Terraform two PostgreSQL databases setup - amazon-web-services

Question

I am very very new to teraform scripting.
Our system is running in AWS and we have a single database server instance accessed by multiple micro services.
Each micro service that needs to persist some data needs to point to a different database (schema) on the same database server. We prefer each service to have its own schema to have the services totally decoupled from each other. However creating a separate database instance to achieve this would be a bit too much as some services only persist close to nothing so it would be a waste,
I created the PostgreSQL resource in a services.tf script that is common to all microservices:
resource "aws_db_instance" "my-system" {
identifier_prefix = "${var.resource_name_prefix}-tlm-"
engine = "postgres"
allocated_storage = "${var.database_storage_size}"
storage_type = "${var.database_storage_type}"
storage_encrypted = true
skip_final_snapshot = true
instance_class = "${var.database_instance_type}"
availability_zone = "${data.aws_availability_zones.all.names[0]}"
db_subnet_group_name = "${aws_db_subnet_group.default.name}"
vpc_security_group_ids = "${var.security_group_ids}"
backup_retention_period = "${var.database_retention_period}"
backup_window = "15:00-18:00" // UTC
maintenance_window = "sat:19:00-sat:20:00" // UTC
tags = "${var.tags}"
}
And now I for my service-1 and service-2 i want to be able to create the corespondent database name. I don't think the below is correct I am just adding it to give you an idea about what I am trying to achieve.
So service-1.tf will contain:
resource "aws_db_instance" "my-system" {
name = "service_1"
}
And service-2.tf will contain:
resource "aws_db_instance" "my-system" {
name = "service_2"
}
My question is what should I put in the service-1.tf and service-2.tf to make this possible.
Thank you in advance for your inputs.

Answer 1

Terraform can only manage at the RDS instance level. Configuring the schema etc is a DBA task.
One way you could automate the DBA tasks is by creating a null_resource using the local-exec provider to use a postgres client to do the work.

Answer 2

you can use count to manage one tf file only
resource "aws_db_instance" "my-system" {
count = "2"
name = "service_${count.index}"
identifier_prefix = "${var.resource_name_prefix}-tlm-"
engine = "postgres"
allocated_storage = "${var.database_storage_size}"
storage_type = "${var.database_storage_type}"
storage_encrypted = true
skip_final_snapshot = true
instance_class = "${var.database_instance_type}"
availability_zone = "${data.aws_availability_zones.all.names[0]}"
db_subnet_group_name = "${aws_db_subnet_group.default.name}"
vpc_security_group_ids = "${var.security_group_ids}"
backup_retention_period = "${var.database_retention_period}"
backup_window = "15:00-18:00" // UTC
maintenance_window = "sat:19:00-sat:20:00" // UTC
tags = "${var.tags}"
}