rds_instance

Use this module for any RDS that is not Aurora. Use the rds_cluster for Aurora instances.

Known issues:

If you receive:

╷ │ Error: Creating CloudWatch Log Group failed: ResourceAlreadyExistsException: The specified log group already exists: The CloudWatch Log Group '/aws/rds/instance/website-stack-20220819105124303000000001/error' already exists. │ │ with module.website_stack.module.website_database.aws_cloudwatch_log_group.log_exports["error"], │ on ../../modules/rds_instance/cloudwatch_logs_exports.tf line 1, in resource "aws_cloudwatch_log_group" "log_exports": │ 1: resource "aws_cloudwatch_log_group" "log_exports" { │ ╵

Upon initial creation then import the resource or delete it and rerun the TerraForm module. The reason this happens is because we want to control automically created CloudWatch log groups. This happens in more places in AWS unfortunately.

max_allocated_storage

This Terraform command uses the coalesce function, which is commonly used to set default values or to check values for null or zero.

max_allocated_storage = coalesce(
    var.max_allocated_storage != null ? (
      var.max_allocated_storage != 0 ? var.max_allocated_storage : null
    ) : null,
    var.max_allocated_storage
)

Explanation:

• coalesce is a Terraform function that selects one of the given values, starting from left to right, and returns the first non-null value. If all values are null, it returns null.

• var.max_allocated_storage != null ? ... : null checks if the variable max_allocated_storage is not null. If it's not null, it proceeds to check if it's not equal to 0. If it's not null and not equal to 0, it uses the value of max_allocated_storage. Otherwise, it returns null.

• If var.max_allocated_storage != null ? ... : null returns null (because var.max_allocated_storage is null), then the default value of null is re-evaluated in the coalesce function, and then the value of var.max_allocated_storage is used.

Providers

Name	Version
aws	>=4.8.0
random	>=3.1.2

Modules

Name	Source	Version
iam_role	git@github.com:wearetechnative/terraform-aws-iam-role.git	v1.0.0

Resources

Name	Type
aws_cloudwatch_log_group.log_exports	resource
aws_db_instance.replica	resource
aws_db_instance.this	resource
aws_db_option_group.this	resource
aws_db_parameter_group.this	resource
aws_db_subnet_group.this	resource
random_password.login_suffix	resource
random_password.password	resource
aws_caller_identity.current	data source

Inputs

Name	Description	Type	Default	Required
additional_tags	Additional tags to be added to resources.	map(string)	{}	no
allocated_storage	Set the amount of storage to be used by RDS.	number	20	no
auto_minor_version_upgrade	Allow minor updates during maintenance window.	bool	true	no
az	specify availability zone for instance if preferred	string	null	no
az_replica	specify availability zone for replica instance if preferred	string	null	no
backup_retention_period	number of days to retain backups	number	35	no
backup_window	Add a window in the folling format: 03:00-04:00	string	"03:00-04:00"	no
db_name	Name of the database to create when the DB instance is created.	string	null	no
deletion_protection	protect the instance from deletion	bool	false	no
enable_aws_backup_tag	To enable aws backup service tag to RDS instance.	bool	false	no
enable_aws_backup_tag_replica	To enable aws backup service tag to RDS replica instance.	bool	false	no
enabled_cloudwatch_logs_exports	Enabled CloudWatch log exports.	list(string)	[ "audit", "error", "general", "slowquery" ]	no
engine	RDS database engine to use.	string	"mariadb"	no
engine_family	RDS database parameter group family.	string	"mariadb10.5"	no
engine_major_version	RDS database engine version to use for option group.	string	"10.5"	no
engine_version	RDS database engine version to use.	string	"10.5.12"	no
instance_class	Instance class to be used for database instance.	string	"db.t3.medium"	no
kms_key_arn	KMS key to use for encrypting RDS instances.	string	n/a	yes
maintenance_window	maintenance window for rds instance updates	string	"Sun:02:00-Sun:03:00"	no
max_allocated_storage	Set the maximum storage to be used by RDS.	number	20	no
multi_az	Use 2 AZs for high availability.	bool	true	no
name	Unique name for RDS instance.	string	n/a	yes
parameter_group_overrides	Optional map of user defined parameters. The map key is the parameter name. The map contains value and apply_method as attributes.	map(object({ value = string apply_method = string }))	{}	no
password	Set a password for username. If set to null, a random password will be created	string	null	no
performance_insights_enabled	performance insights	bool	false	no
performance_insights_retention_period	Retention period of performance insights data	number	31	no
replica	create a read replica or not	bool	false	no
security_group_ids	Provide at least one security group to be associated with this instance.	list(string)	n/a	yes
storage_io1_iops	Overrides storage_type to io1 if set and defines the provisioned iops required.	number	null	no
storage_type	Storage type to be used for instances.	string	"gp2"	no
subnet_ids	Required list of subnets to launch instances in.	list(string)	n/a	yes
username	Set a username for database. If set to null, a random username will be created	string	null	no

Outputs

Name	Description
db_dns_address	n/a
db_name	n/a
db_port	n/a
domain	n/a
instance_arn	n/a
master_db_user_name	n/a
master_db_user_password	n/a