Remove subnet and parameter groups

Instead of defining RDS subnet groups and parameter groups, emit the necessary IDs so that the module consumer can specify their own customized resources.
azavea · Jul 25, 2016 · a288187 · a288187
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commit a288187
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Showing 3 changed files with 72 additions and 73 deletions.
diff --git a/README.md b/README.md
@@ -9,12 +9,12 @@ module "postgresql_rds" {
   source = "github.com/azavea/terraform-aws-postgresql-rds"
 
   vpc_id = "vpc-20f74844"
-  vpc_cidr_block = "10.0.0.0/16"
 
   allocated_storage = "32"
   engine_version = "9.4.4"
   instance_type = "db.t2.micro"
   storage_type = "gp2"
+  database_identifier = "jl23kj32sdf"
   database_name = "hector"
   database_username = "hector"
   database_password = "secret"
@@ -24,11 +24,15 @@ module "postgresql_rds" {
   auto_minor_version_upgrade = false
   multi_availability_zone = true
   storage_encrypted = false
+  subnet_group = "${aws_db_subnet_group.default.name}"
+  parameter_group = "${aws_db_parameter_group.default.name}"
 
-  private_subnet_ids = "subnet-4a887f3c,subnet-76dae35d"
-  parameter_group_family = "postgres9.4"
-
+  alarm_cpu_threshold = 75
+  alarm_disk_queue_threshold = 10
+  alarm_free_disk_threshold = 5000000000
+  alarm_free_memory_threshold = 128000000
   alarm_actions = "arn:aws:sns..."
+
   project = "Something"
   environment = "Staging"
 }
@@ -39,11 +43,11 @@ module "postgresql_rds" {
 - `project` - Name of project this VPC is meant to house (default: `Unknown`)
 - `environment` - Name of environment this VPC is targeting (default: `Unknown`)
 - `vpc_id` - ID of VPC meant to house database
-- `vpc_cidr_block` - CIDR block of VPC
 - `allocated_storage` - Storage allocated to database instance (default: `32`)
 - `engine_version` - Database engine version (default: `9.4.4`)
 - `instance_type` - Instance type for database instance (default: `db.t2.micro`)
 - `storage_type` - Type of underlying storage for database (default: `gp2`)
+- `database_identifier` - Identifier for RDS instance
 - `database_name` - Name of database inside storage engine
 - `database_username` - Name of user inside storage engine
 - `database_password` - Database password inside storage engine
@@ -58,9 +62,13 @@ module "postgresql_rds" {
 - `multi_availability_zone` - Flag to enable hot standby in another availability
   zone (default: `false`)
 - `storage_encrypted` - Flag to enable storage encryption (default: `false`)
-- `private_subnet_ids` - Comma delimited list of private subnet IDs
-- `parameter_group_family` - Database engine parameter group family (default:
-  `postgres9.4`)
+- `subnet_group` - Database subnet group
+- `parameter_group` - Database engine parameter group (default:
+  `default.postgres9.4`)
+- `alarm_cpu_threshold` - CPU alarm threshold as a percentage (default: `75`)
+- `alarm_disk_queue_threshold` - Disk queue alarm threshold (default: `10`)
+- `alarm_free_disk_threshold` - Free disk alarm threshold in bytes (default: `5000000000`)
+- `alarm_free_memory_threshold` - Free memory alarm threshold in bytes (default: `128000000`)
 - `alarm_actions` - Comma delimited list of ARNs to be notified via CloudWatch
 
 ## Outputs

diff --git a/main.tf b/main.tf
@@ -17,66 +17,46 @@ resource "aws_security_group" "postgresql" {
 #
 
 resource "aws_db_instance" "postgresql" {
-  allocated_storage          = "${var.allocated_storage}"
-  engine                     = "postgres"
-  engine_version             = "${var.engine_version}"
-  identifier                 = "${var.database_name}"
-  instance_class             = "${var.instance_type}"
-  storage_type               = "${var.storage_type}"
-  name                       = "${var.database_name}"
-  password                   = "${var.database_password}"
-  username                   = "${var.database_username}"
-  backup_retention_period    = "${var.backup_retention_period}"
-  backup_window              = "${var.backup_window}"
-  maintenance_window         = "${var.maintenance_window}"
-  auto_minor_version_upgrade = "${var.auto_minor_version_upgrade}"
-  multi_az                   = "${var.multi_availability_zone}"
-  port                       = "5432"
-  vpc_security_group_ids     = ["${aws_security_group.postgresql.id}"]
-  db_subnet_group_name       = "${aws_db_subnet_group.default.name}"
-  parameter_group_name       = "${aws_db_parameter_group.default.name}"
-  storage_encrypted          = "${var.storage_encrypted}"
+  allocated_storage       = "${var.allocated_storage}"
+  engine                  = "postgres"
+  engine_version          = "${var.engine_version}"
+  identifier              = "${var.database_identifier}"
+  instance_class          = "${var.instance_type}"
+  storage_type            = "${var.storage_type}"
+  name                    = "${var.database_name}"
+  password                = "${var.database_password}"
+  username                = "${var.database_username}"
+  backup_retention_period = "${var.backup_retention_period}"
+  backup_window           = "${var.backup_window}"
+  maintenance_window      = "${var.maintenance_window}"
+  multi_az                = "${var.multi_availability_zone}"
+  port                    = "5432"
+  vpc_security_group_ids  = ["${aws_security_group.postgresql.id}"]
+  db_subnet_group_name    = "${var.subnet_group}"
+  parameter_group_name    = "${var.parameter_group}"
+  storage_encrypted       = "${var.storage_encrypted}"
 
   tags {
-    Name = "DatabaseServer"
-  }
-}
-
-resource "aws_db_subnet_group" "default" {
-  name        = "${var.database_name}-subnet-group"
-  description = "Private subnets for the RDS instances"
-  subnet_ids  = ["${split(",", var.private_subnet_ids)}"]
-
-  tags {
-    Name = "dbsngDatabaseServer"
-  }
-}
-
-resource "aws_db_parameter_group" "default" {
-  name        = "${var.database_name}-parameter-group"
-  description = "Parameter group for the RDS instances"
-  family      = "${var.parameter_group_family}"
-
-  parameter {
-    name  = "log_min_duration_statement"
-    value = "500"
+    Name        = "DatabaseServer"
+    Project     = "${var.project}"
+    Environment = "${var.environment}"
   }
 }
 
 #
 # CloudWatch resources
 #
 
-resource "aws_cloudwatch_metric_alarm" "cpu" {
-  alarm_name          = "alarmDatabaseServerCPUUtilization-${var.database_name}"
+resource "aws_cloudwatch_metric_alarm" "database_cpu" {
+  alarm_name          = "alarm${var.environment}DatabaseServerCPUUtilization"
   alarm_description   = "Database server CPU utilization"
   comparison_operator = "GreaterThanThreshold"
   evaluation_periods  = "1"
   metric_name         = "CPUUtilization"
   namespace           = "AWS/RDS"
   period              = "300"
   statistic           = "Average"
-  threshold           = "75"
+  threshold           = "${var.alarm_cpu_threshold}"
 
   dimensions {
     DBInstanceIdentifier = "${aws_db_instance.postgresql.id}"
@@ -85,16 +65,16 @@ resource "aws_cloudwatch_metric_alarm" "cpu" {
   alarm_actions = ["${split(",", var.alarm_actions)}"]
 }
 
-resource "aws_cloudwatch_metric_alarm" "disk_queue" {
-  alarm_name          = "alarmDatabaseServerDiskQueueDepth-${var.database_name}"
+resource "aws_cloudwatch_metric_alarm" "database_disk_queue" {
+  alarm_name          = "alarm${var.environment}DatabaseServerDiskQueueDepth"
   alarm_description   = "Database server disk queue depth"
   comparison_operator = "GreaterThanThreshold"
   evaluation_periods  = "1"
   metric_name         = "DiskQueueDepth"
   namespace           = "AWS/RDS"
   period              = "60"
   statistic           = "Average"
-  threshold           = "10"
+  threshold           = "${var.alarm_disk_queue_threshold}"
 
   dimensions {
     DBInstanceIdentifier = "${aws_db_instance.postgresql.id}"
@@ -103,18 +83,16 @@ resource "aws_cloudwatch_metric_alarm" "disk_queue" {
   alarm_actions = ["${split(",", var.alarm_actions)}"]
 }
 
-resource "aws_cloudwatch_metric_alarm" "disk_free" {
-  alarm_name          = "alarmDatabaseServerFreeStorageSpace-${var.database_name}"
+resource "aws_cloudwatch_metric_alarm" "database_disk_free" {
+  alarm_name          = "alarm${var.environment}DatabaseServerFreeStorageSpace"
   alarm_description   = "Database server free storage space"
   comparison_operator = "LessThanThreshold"
   evaluation_periods  = "1"
   metric_name         = "FreeStorageSpace"
   namespace           = "AWS/RDS"
   period              = "60"
   statistic           = "Average"
-
-  # 5GB in bytes
-  threshold = "5000000000"
+  threshold           = "${var.alarm_free_disk_threshold}"
 
   dimensions {
     DBInstanceIdentifier = "${aws_db_instance.postgresql.id}"
@@ -123,24 +101,19 @@ resource "aws_cloudwatch_metric_alarm" "disk_free" {
   alarm_actions = ["${split(",", var.alarm_actions)}"]
 }
 
-resource "aws_cloudwatch_metric_alarm" "memory_free" {
-  alarm_name          = "alarmDatabaseServerFreeableMemory-${var.database_name}"
+resource "aws_cloudwatch_metric_alarm" "database_memory_free" {
+  alarm_name          = "alarm${var.environment}DatabaseServerFreeableMemory"
   alarm_description   = "Database server freeable memory"
   comparison_operator = "LessThanThreshold"
   evaluation_periods  = "1"
   metric_name         = "FreeableMemory"
   namespace           = "AWS/RDS"
   period              = "60"
   statistic           = "Average"
-
-  # 128MB in bytes
-  threshold = "128000000"
+  threshold           = "${var.alarm_free_memory_threshold}"
 
   dimensions {
     DBInstanceIdentifier = "${aws_db_instance.postgresql.id}"
-    Name        = "DatabaseServer"
-    Project     = "${var.project}"
-    Environment = "${var.environment}"
   }
 
   alarm_actions = ["${split(",", var.alarm_actions)}"]

diff --git a/variables.tf b/variables.tf
@@ -8,8 +8,6 @@ variable "environment" {
 
 variable "vpc_id" {}
 
-variable "vpc_cidr_block" {}
-
 variable "allocated_storage" {
   default = "32"
 }
@@ -26,6 +24,8 @@ variable "storage_type" {
   default = "gp2"
 }
 
+variable "database_identifier" {}
+
 variable "database_name" {}
 
 variable "database_password" {}
@@ -58,10 +58,28 @@ variable "storage_encrypted" {
   default = false
 }
 
-variable "private_subnet_ids" {}
+variable "subnet_group" {}
+
+variable "parameter_group" {
+  default = "default.postgres9.4"
+}
+
+variable "alarm_cpu_threshold" {
+  default = 75
+}
+
+variable "alarm_disk_queue_threshold" {
+  default = 10
+}
+
+variable "alarm_free_disk_threshold" {
+  # 5GB
+  default = 5000000000
+}
 
-variable "parameter_group_family" {
-  default = "postgres9.5"
+variable "alarm_free_memory_threshold" {
+  # 128MB
+  default = 128000000
 }
 
 variable "alarm_actions" {}