This component is responsible for provisioning Aurora Postgres RDS clusters. It seeds relevant database information (hostnames, username, password, etc.) into AWS SSM Parameter Store.

Usage

Stack Level: Regional

Here's an example for how to use this component.

stacks/catalog/aurora-postgres/defaults.yaml file (base component for all Aurora Postgres clusters with default settings):

components:
  terraform:
    aurora-postgres/defaults:
      metadata:
        type: abstract
      vars:
        enabled: true
        name: aurora-postgres
        tags:
          Team: sre
          Service: aurora-postgres
        cluster_name: shared
        deletion_protection: false
        storage_encrypted: true
        engine: aurora-postgresql

        # Provisioned configuration
        engine_mode: provisioned
        engine_version: "15.3"
        cluster_family: aurora-postgresql15
        # 1 writer, 1 reader
        cluster_size: 2
        # https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/Concepts.DBInstanceClass.html
        instance_type: db.t3.medium

        admin_user: postgres
        admin_password: "" # generate random password
        database_name: postgres
        database_port: 5432
        skip_final_snapshot: false
        # Enhanced Monitoring
        # A boolean flag to enable/disable the creation of the enhanced monitoring IAM role.
        # If set to false, the module will not create a new role and will use rds_monitoring_role_arn for enhanced monitoring
        enhanced_monitoring_role_enabled: true
        # The interval, in seconds, between points when enhanced monitoring metrics are collected for the DB instance.
        # To disable collecting Enhanced Monitoring metrics, specify 0. The default is 0. Valid Values: 0, 1, 5, 10, 15, 30, 60
        rds_monitoring_interval: 15
        # Allow ingress from the following accounts
        # If any of tenant, stage, or environment aren't given, this will be taken
        allow_ingress_from_vpc_accounts:
          - tenant: core
            stage: auto

Example (not actual):

stacks/uw2-dev.yaml file (override the default settings for the cluster in the dev account, create an additional database and user):

import:
  - catalog/aurora-postgres/defaults

components:
  terraform:
    aurora-postgres:
      metadata:
        component: aurora-postgres
        inherits:
          - aurora-postgres/defaults
      vars:
        enabled: true

Finding Aurora Engine Version

Use the following to query the AWS API by engine-mode. Both provisioned and Serverless v2 use the privisoned engine mode, whereas only Serverless v1 uses the serverless engine mode.

aws rds describe-db-engine-versions \
  --engine aurora-postgresql \
  --query 'DBEngineVersions[].EngineVersion' \
  --filters 'Name=engine-mode,Values=serverless'

Use the following to query AWS API by db-instance-class. Use this query to find supported versions for a specific instance class, such as db.serverless with Serverless v2.

aws rds describe-orderable-db-instance-options \
  --engine aurora-postgresql \
  --db-instance-class db.serverless \
  --query 'OrderableDBInstanceOptions[].[EngineVersion]'

Once a version has been selected, use the following to find the cluster family.

aws rds describe-db-engine-versions --engine aurora-postgresql --query "DBEngineVersions[]" | \
jq '.[] | select(.EngineVersion == "15.3") |
  { Engine: .Engine, EngineVersion: .EngineVersion, DBParameterGroupFamily: .DBParameterGroupFamily }'

Examples

Generally there are three different engine configurations for Aurora: provisioned, Serverless v1, and Serverless v2.

Provisioned Aurora Postgres

See the default usage example above

Serverless v1 Aurora Postgres

Serverless v1 requires engine-mode set to serverless uses scaling_configuration to configure scaling options.

For valid values, see ModifyCurrentDBClusterCapacity.

components:
  terraform:
    aurora-postgres:
      vars:
        enabled: true
        name: aurora-postgres
        eks_component_names:
          - eks/cluster
        allow_ingress_from_vpc_accounts:
          # Allows Spacelift
          - tenant: core
            stage: auto
            environment: use2
          # Allows VPN
          - tenant: core
            stage: network
            environment: use2
        cluster_name: shared
        engine: aurora-postgresql

        # Serverless v1 configuration
        engine_mode: serverless
        instance_type: "" # serverless engine_mode ignores `var.instance_type`
        engine_version: "13.9" # Latest supported version as of 08/28/2023
        cluster_family: aurora-postgresql13
        cluster_size: 0 # serverless
        scaling_configuration:
          - auto_pause: true
            max_capacity: 5
            min_capacity: 2
            seconds_until_auto_pause: 300
            timeout_action: null

        admin_user: postgres
        admin_password: "" # generate random password
        database_name: postgres
        database_port: 5432
        storage_encrypted: true
        deletion_protection: true
        skip_final_snapshot: false
        # Creating read-only users or additional databases requires Spacelift
        read_only_users_enabled: false
        # Enhanced Monitoring
        # A boolean flag to enable/disable the creation of the enhanced monitoring IAM role.
        # If set to false, the module will not create a new role and will use rds_monitoring_role_arn for enhanced monitoring
        enhanced_monitoring_role_enabled: true
        enhanced_monitoring_attributes: ["monitoring"]
        # The interval, in seconds, between points when enhanced monitoring metrics are collected for the DB instance.
        # To disable collecting Enhanced Monitoring metrics, specify 0. The default is 0. Valid Values: 0, 1, 5, 10, 15, 30, 60
        rds_monitoring_interval: 15
        iam_database_authentication_enabled: false
        additional_users: {}

Serverless v2 Aurora Postgres

Aurora Postgres Serverless v2 uses the provisioned engine mode with db.serverless instances. In order to configure scaling with Serverless v2, use var.serverlessv2_scaling_configuration.

For more on valid scaling configurations, see Performance and scaling for Aurora Serverless v2.

components:
  terraform:
    aurora-postgres:
      vars:
        enabled: true
        name: aurora-postgres
        eks_component_names:
          - eks/cluster
        allow_ingress_from_vpc_accounts:
          # Allows Spacelift
          - tenant: core
            stage: auto
            environment: use2
          # Allows VPN
          - tenant: core
            stage: network
            environment: use2
        cluster_name: shared
        engine: aurora-postgresql

        # Serverless v2 configuration
        engine_mode: provisioned
        instance_type: "db.serverless"
        engine_version: "15.3"
        cluster_family: aurora-postgresql15
        cluster_size: 2
        serverlessv2_scaling_configuration:
          min_capacity: 2
          max_capacity: 64

        admin_user: postgres
        admin_password: "" # generate random password
        database_name: postgres
        database_port: 5432
        storage_encrypted: true
        deletion_protection: true
        skip_final_snapshot: false
        # Creating read-only users or additional databases requires Spacelift
        read_only_users_enabled: false
        # Enhanced Monitoring
        # A boolean flag to enable/disable the creation of the enhanced monitoring IAM role.
        # If set to false, the module will not create a new role and will use rds_monitoring_role_arn for enhanced monitoring
        enhanced_monitoring_role_enabled: true
        enhanced_monitoring_attributes: ["monitoring"]
        # The interval, in seconds, between points when enhanced monitoring metrics are collected for the DB instance.
        # To disable collecting Enhanced Monitoring metrics, specify 0. The default is 0. Valid Values: 0, 1, 5, 10, 15, 30, 60
        rds_monitoring_interval: 15
        iam_database_authentication_enabled: false
        additional_users: {}

Requirements

Name	Version
terraform	>= 1.3.0
aws	>= 4.9.0
postgresql	>= 1.17.1
random	>= 2.3

Providers

Name	Version
aws	>= 4.9.0
random	>= 2.3

Modules

Name	Source	Version
aurora_postgres_cluster	cloudposse/rds-cluster/aws	1.3.2
cluster	cloudposse/label/null	0.25.0
dns_gbl_delegated	cloudposse/stack-config/yaml//modules/remote-state	1.5.0
eks	cloudposse/stack-config/yaml//modules/remote-state	1.5.0
iam_roles	../account-map/modules/iam-roles	n/a
kms_key_rds	cloudposse/kms-key/aws	0.12.1
parameter_store_write	cloudposse/ssm-parameter-store/aws	0.11.0
this	cloudposse/label/null	0.25.0
vpc	cloudposse/stack-config/yaml//modules/remote-state	1.5.0
vpc_ingress	cloudposse/stack-config/yaml//modules/remote-state	1.5.0

Resources

Name	Type
random_password.admin_password	resource
random_pet.admin_user	resource
random_pet.database_name	resource
aws_caller_identity.current	data source
aws_iam_policy_document.kms_key_rds	data source
aws_partition.current	data source
aws_security_groups.allowed	data source

Inputs

Name	Description	Type	Default	Required
additional_tag_map	Additional key-value pairs to add to each map in tags_as_list_of_maps. Not added to tags or id. This is for some rare cases where resources want additional configuration of tags and therefore take a list of maps with tag key, value, and additional configuration.	map(string)	{}	no
admin_password	Postgres password for the admin user	string	""	no
admin_user	Postgres admin user name	string	""	no
allow_ingress_from_vpc_accounts	List of account contexts to pull VPC ingress CIDR and add to cluster security group. e.g. { environment = "ue2", stage = "auto", tenant = "core" } Defaults to the "vpc" component in the given account	list(object({ vpc = optional(string, "vpc") environment = optional(string) stage = optional(string) tenant = optional(string) }))	[]	no
allow_major_version_upgrade	Enable to allow major engine version upgrades when changing engine versions. Defaults to false.	bool	false	no
allowed_cidr_blocks	List of CIDRs allowed to access the database (in addition to security groups and subnets)	list(string)	[]	no
allowed_security_group_names	List of security group names (tags) that should be allowed access to the database	list(string)	[]	no
attributes	ID element. Additional attributes (e.g. workers or cluster) to add to id, in the order they appear in the list. New attributes are appended to the end of the list. The elements of the list are joined by the delimiter and treated as a single ID element.	list(string)	[]	no
autoscaling_enabled	Whether to enable cluster autoscaling	bool	false	no
autoscaling_max_capacity	Maximum number of instances to be maintained by the autoscaler	number	5	no
autoscaling_min_capacity	Minimum number of instances to be maintained by the autoscaler	number	1	no
autoscaling_policy_type	Autoscaling policy type. TargetTrackingScaling and StepScaling are supported	string	"TargetTrackingScaling"	no
autoscaling_scale_in_cooldown	The amount of time, in seconds, after a scaling activity completes and before the next scaling down activity can start. Default is 300s	number	300	no
autoscaling_scale_out_cooldown	The amount of time, in seconds, after a scaling activity completes and before the next scaling up activity can start. Default is 300s	number	300	no
autoscaling_target_metrics	The metrics type to use. If this value isn't provided the default is CPU utilization	string	"RDSReaderAverageCPUUtilization"	no
autoscaling_target_value	The target value to scale with respect to target metrics	number	75	no
backup_window	Daily time range during which the backups happen, UTC	string	"07:00-09:00"	no
ca_cert_identifier	The identifier of the CA certificate for the DB instance	string	null	no
cluster_dns_name_part	Part of DNS name added to module and cluster name for DNS for cluster endpoint	string	"writer"	no
cluster_family	Family of the DB parameter group. Valid values for Aurora PostgreSQL: aurora-postgresql9.6, aurora-postgresql10, aurora-postgresql11, aurora-postgresql12	string	"aurora-postgresql13"	no
cluster_name	Short name for this cluster	string	n/a	yes
cluster_parameters	List of DB cluster parameters to apply	list(object({ apply_method = string name = string value = string }))	[]	no
cluster_size	Postgres cluster size	number	n/a	yes
context	Single object for setting entire context at once. See description of individual variables for details. Leave string and numeric variables as null to use default value. Individual variable settings (non-null) override settings in context object, except for attributes, tags, and additional_tag_map, which are merged.	any	{ "additional_tag_map": {}, "attributes": [], "delimiter": null, "descriptor_formats": {}, "enabled": true, "environment": null, "id_length_limit": null, "label_key_case": null, "label_order": [], "label_value_case": null, "labels_as_tags": [ "unset" ], "name": null, "namespace": null, "regex_replace_chars": null, "stage": null, "tags": {}, "tenant": null }	no
database_name	Name for an automatically created database on cluster creation. An empty name will generate a db name.	string	""	no
database_port	Database port	number	5432	no
deletion_protection	Specifies whether the Cluster should have deletion protection enabled. The database can't be deleted when this value is set to true	bool	false	no
delimiter	Delimiter to be used between ID elements. Defaults to - (hyphen). Set to "" to use no delimiter at all.	string	null	no
descriptor_formats	Describe additional descriptors to be output in the descriptors output map. Map of maps. Keys are names of descriptors. Values are maps of the form {<br/> format = string<br/> labels = list(string)<br/>} (Type is any so the map values can later be enhanced to provide additional options.) format is a Terraform format string to be passed to the format() function. labels is a list of labels, in order, to pass to format() function. Label values will be normalized before being passed to format() so they will be identical to how they appear in id. Default is {} (descriptors output will be empty).	any	{}	no
dns_gbl_delegated_environment_name	The name of the environment where global dns_delegated is provisioned	string	"gbl"	no
eks_component_names	The names of the eks components	set(string)	[ "eks/cluster" ]	no
eks_security_group_enabled	Use the eks default security group	bool	false	no
enabled	Set to false to prevent the module from creating any resources	bool	null	no
enabled_cloudwatch_logs_exports	List of log types to export to cloudwatch. The following log types are supported: audit, error, general, slowquery	list(string)	[]	no
engine	Name of the database engine to be used for the DB cluster	string	"postgresql"	no
engine_mode	The database engine mode. Valid values: global, multimaster, parallelquery, provisioned, serverless	string	n/a	yes
engine_version	Engine version of the Aurora global database	string	"13.4"	no
enhanced_monitoring_attributes	Attributes used to format the Enhanced Monitoring IAM role. If this role hits IAM role length restrictions (max 64 characters), consider shortening these strings.	list(string)	[ "enhanced-monitoring" ]	no
enhanced_monitoring_role_enabled	A boolean flag to enable/disable the creation of the enhanced monitoring IAM role. If set to false, the module will not create a new role and will use rds_monitoring_role_arn for enhanced monitoring	bool	true	no
environment	ID element. Usually used for region e.g. 'uw2', 'us-west-2', OR role 'prod', 'staging', 'dev', 'UAT'	string	null	no
iam_database_authentication_enabled	Specifies whether or mappings of AWS Identity and Access Management (IAM) accounts to database accounts is enabled	bool	false	no
id_length_limit	Limit id to this many characters (minimum 6). Set to 0 for unlimited length. Set to null for keep the existing setting, which defaults to 0. Does not affect id_full.	number	null	no
instance_type	EC2 instance type for Postgres cluster	string	n/a	yes
intra_security_group_traffic_enabled	Whether to allow traffic between resources inside the database's security group.	bool	false	no
label_key_case	Controls the letter case of the tags keys (label names) for tags generated by this module. Does not affect keys of tags passed in via the tags input. Possible values: lower, title, upper. Default value: title.	string	null	no
label_order	The order in which the labels (ID elements) appear in the id. Defaults to ["namespace", "environment", "stage", "name", "attributes"]. You can omit any of the 6 labels ("tenant" is the 6th), but at least one must be present.	list(string)	null	no
label_value_case	Controls the letter case of ID elements (labels) as included in id, set as tag values, and output by this module individually. Does not affect values of tags passed in via the tags input. Possible values: lower, title, upper and none (no transformation). Set this to title and set delimiter to "" to yield Pascal Case IDs. Default value: lower.	string	null	no
labels_as_tags	Set of labels (ID elements) to include as tags in the tags output. Default is to include all labels. Tags with empty values will not be included in the tags output. Set to [] to suppress all generated tags. Notes: The value of the name tag, if included, will be the id, not the name. Unlike other null-label inputs, the initial setting of labels_as_tags cannot be changed in later chained modules. Attempts to change it will be silently ignored.	set(string)	[ "default" ]	no
maintenance_window	Weekly time range during which system maintenance can occur, in UTC	string	"wed:03:00-wed:04:00"	no
name	ID element. Usually the component or solution name, e.g. 'app' or 'jenkins'. This is the only ID element not also included as a tag. The "name" tag is set to the full id string. There is no tag with the value of the name input.	string	null	no
namespace	ID element. Usually an abbreviation of your organization name, e.g. 'eg' or 'cp', to help ensure generated IDs are globally unique	string	null	no
performance_insights_enabled	Whether to enable Performance Insights	bool	false	no
publicly_accessible	Set true to make this database accessible from the public internet	bool	false	no
rds_monitoring_interval	The interval, in seconds, between points when enhanced monitoring metrics are collected for the DB instance. To disable collecting Enhanced Monitoring metrics, specify 0. The default is 0. Valid Values: 0, 1, 5, 10, 15, 30, 60	number	60	no
reader_dns_name_part	Part of DNS name added to module and cluster name for DNS for cluster reader	string	"reader"	no
regex_replace_chars	Terraform regular expression (regex) string. Characters matching the regex will be removed from the ID elements. If not set, "/[^a-zA-Z0-9-]/" is used to remove all characters other than hyphens, letters and digits.	string	null	no
region	AWS Region	string	n/a	yes
retention_period	Number of days to retain backups for	number	5	no
scaling_configuration	List of nested attributes with scaling properties. Only valid when engine_mode is set to serverless. This is required for Serverless v1	list(object({ auto_pause = bool max_capacity = number min_capacity = number seconds_until_auto_pause = number timeout_action = string }))	[]	no
serverlessv2_scaling_configuration	Nested attribute with scaling properties for ServerlessV2. Only valid when engine_mode is set to provisioned. This is required for Serverless v2	object({ min_capacity = number max_capacity = number })	null	no
skip_final_snapshot	Normally AWS makes a snapshot of the database before deleting it. Set this to true in order to skip this. NOTE: The final snapshot has a name derived from the cluster name. If you delete a cluster, get a final snapshot, then create a cluster of the same name, its final snapshot will fail with a name collision unless you delete the previous final snapshot first.	bool	false	no
snapshot_identifier	Specifies whether or not to create this cluster from a snapshot	string	null	no
ssm_cluster_name_override	Set a cluster name into the ssm path prefix	string	""	no
ssm_path_prefix	Top level SSM path prefix (without leading or trailing slash)	string	"aurora-postgres"	no
stage	ID element. Usually used to indicate role, e.g. 'prod', 'staging', 'source', 'build', 'test', 'deploy', 'release'	string	null	no
storage_encrypted	Specifies whether the DB cluster is encrypted	bool	true	no
tags	Additional tags (e.g. {'BusinessUnit': 'XYZ'}). Neither the tag keys nor the tag values will be modified by this module.	map(string)	{}	no
tenant	ID element _(Rarely used, not included by default)_. A customer identifier, indicating who this instance of a resource is for	string	null	no
vpc_component_name	The name of the VPC component	string	"vpc"	no

Outputs

Name	Description
admin_username	Postgres admin username
allowed_security_groups	The resulting list of security group IDs that are allowed to connect to the Aurora Postgres cluster.
cluster_identifier	Postgres cluster identifier
config_map	Map containing information pertinent to a PostgreSQL client configuration.
database_name	Postgres database name
kms_key_arn	KMS key ARN for Aurora Postgres
master_hostname	Postgres master hostname
replicas_hostname	Postgres replicas hostname
ssm_key_paths	Names (key paths) of all SSM parameters stored for this cluster

References

• cloudposse/terraform-aws-components - Cloud Posse's upstream component

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