aurora-postgres

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: {}

Variables

Required Variables

cluster_name (string) required: Short name for this cluster
cluster_size (number) required: Postgres cluster size
engine_mode (string) required: The database engine mode. Valid values: global, multimaster, parallelquery, provisioned, serverless
instance_type (string) required: EC2 instance type for Postgres cluster
region (string) required: AWS Region

Optional Variables

admin_password (string) optional

Postgres password for the admin user

Default value: ""

admin_user (string) optional

Postgres admin user name

Default value: ""

allow_ingress_from_vpc_accounts optional

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

Type:

list(object({
vpc         = optional(string, "vpc")
environment = optional(string)
stage       = optional(string)
tenant      = optional(string)
}))

Default value: [ ]

allow_major_version_upgrade (bool) optional

Enable to allow major engine version upgrades when changing engine versions. Defaults to false.

Default value: false

allowed_cidr_blocks (list(string)) optional

List of CIDRs allowed to access the database (in addition to security groups and subnets)

Default value: [ ]

allowed_security_group_names (list(string)) optional

List of security group names (tags) that should be allowed access to the database

Default value: [ ]

autoscaling_enabled (bool) optional

Whether to enable cluster autoscaling

Default value: false

autoscaling_max_capacity (number) optional

Maximum number of instances to be maintained by the autoscaler

Default value: 5

autoscaling_min_capacity (number) optional

Minimum number of instances to be maintained by the autoscaler

Default value: 1

autoscaling_policy_type (string) optional

Autoscaling policy type. TargetTrackingScaling and StepScaling are supported

Default value: "TargetTrackingScaling"

autoscaling_scale_in_cooldown (number) optional

The amount of time, in seconds, after a scaling activity completes and before the next scaling down activity can start. Default is 300s

Default value: 300

autoscaling_scale_out_cooldown (number) optional

The amount of time, in seconds, after a scaling activity completes and before the next scaling up activity can start. Default is 300s

Default value: 300

autoscaling_target_metrics (string) optional

The metrics type to use. If this value isn't provided the default is CPU utilization

Default value: "RDSReaderAverageCPUUtilization"

autoscaling_target_value (number) optional

The target value to scale with respect to target metrics

Default value: 75

backup_window (string) optional

Daily time range during which the backups happen, UTC

Default value: "07:00-09:00"

ca_cert_identifier (string) optional

The identifier of the CA certificate for the DB instance

Default value: null

cluster_dns_name_part (string) optional

Part of DNS name added to module and cluster name for DNS for cluster endpoint

Default value: "writer"

cluster_family (string) optional

Family of the DB parameter group. Valid values for Aurora PostgreSQL: aurora-postgresql9.6, aurora-postgresql10, aurora-postgresql11, aurora-postgresql12

Default value: "aurora-postgresql13"

cluster_parameters optional

List of DB cluster parameters to apply

Type:

list(object({
apply_method = string
name         = string
value        = string
}))

Default value: [ ]

database_name (string) optional

Name for an automatically created database on cluster creation. An empty name will generate a db name.

Default value: ""

database_port (number) optional

Database port

Default value: 5432

deletion_protection (bool) optional

Specifies whether the Cluster should have deletion protection enabled. The database can't be deleted when this value is set to true

Default value: false

dns_gbl_delegated_environment_name (string) optional

The name of the environment where global dns_delegated is provisioned

Default value: "gbl"

eks_component_names (set(string)) optional

The names of the eks components

Default value:

[
  "eks/cluster"
]

eks_security_group_enabled (bool) optional

Use the eks default security group

Default value: false

enabled_cloudwatch_logs_exports (list(string)) optional

List of log types to export to cloudwatch. The following log types are supported: audit, error, general, slowquery

Default value: [ ]

engine (string) optional

Name of the database engine to be used for the DB cluster

Default value: "postgresql"

engine_version (string) optional

Engine version of the Aurora global database

Default value: "13.4"

enhanced_monitoring_attributes (list(string)) optional

Attributes used to format the Enhanced Monitoring IAM role. If this role hits IAM role length restrictions (max 64 characters), consider shortening these strings.

Default value:

[
  "enhanced-monitoring"
]

enhanced_monitoring_role_enabled (bool) optional

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

Default value: true

iam_database_authentication_enabled (bool) optional

Specifies whether or mappings of AWS Identity and Access Management (IAM) accounts to database accounts is enabled

Default value: false

intra_security_group_traffic_enabled (bool) optional

Whether to allow traffic between resources inside the database's security group.

Default value: false

maintenance_window (string) optional

Weekly time range during which system maintenance can occur, in UTC

Default value: "wed:03:00-wed:04:00"

performance_insights_enabled (bool) optional

Whether to enable Performance Insights

Default value: false

publicly_accessible (bool) optional

Set true to make this database accessible from the public internet

Default value: false

rds_monitoring_interval (number) optional

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

Default value: 60

reader_dns_name_part (string) optional

Part of DNS name added to module and cluster name for DNS for cluster reader

Default value: "reader"

retention_period (number) optional

Number of days to retain backups for

Default value: 5

scaling_configuration optional

List of nested attributes with scaling properties. Only valid when engine_mode is set to serverless. This is required for Serverless v1

Type:

list(object({
auto_pause               = bool
max_capacity             = number
min_capacity             = number
seconds_until_auto_pause = number
timeout_action           = string
}))

Default value: [ ]

serverlessv2_scaling_configuration optional

Nested attribute with scaling properties for ServerlessV2. Only valid when engine_mode is set to provisioned. This is required for Serverless v2

Type:

object({
min_capacity = number
max_capacity = number
})

Default value: null

skip_final_snapshot (bool) optional

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.

Default value: false

snapshot_identifier (string) optional

Specifies whether or not to create this cluster from a snapshot

Default value: null

ssm_path_prefix (string) optional

Top level SSM path prefix (without leading or trailing slash)

Default value: "aurora-postgres"

storage_encrypted (bool) optional

Specifies whether the DB cluster is encrypted

Default value: true

vpc_component_name (string) optional

The name of the VPC component

Default value: "vpc"

Context Variables

The following variables are defined in the context.tf file of this module and part of the terraform-null-label pattern.

additional_tag_map (map(string)) optional

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.

Required: No

Default value: { }

attributes (list(string)) optional

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.

Required: No

Default value: [ ]

context (any) optional

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.

Required: No

Default value:

{
  "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
}

delimiter (string) optional

Delimiter to be used between ID elements.
Defaults to - (hyphen). Set to "" to use no delimiter at all.

Required: No

Default value: null

descriptor_formats (any) optional

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).

Required: No

Default value: { }

enabled (bool) optional

Set to false to prevent the module from creating any resources
Required: No

Default value: null

environment (string) optional

ID element. Usually used for region e.g. 'uw2', 'us-west-2', OR role 'prod', 'staging', 'dev', 'UAT'
Required: No

Default value: null

id_length_limit (number) optional

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.

Required: No

Default value: null

label_key_case (string) optional

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.

Required: No

Default value: null

label_order (list(string)) optional

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.

Required: No

Default value: null

label_value_case (string) optional

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.

Required: No

Default value: null

labels_as_tags (set(string)) optional

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.

Required: No

Default value:

[
  "default"
]

name (string) optional

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.

Required: No

Default value: null

namespace (string) optional

ID element. Usually an abbreviation of your organization name, e.g. 'eg' or 'cp', to help ensure generated IDs are globally unique
Required: No

Default value: null

regex_replace_chars (string) optional

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.

Required: No

Default value: null

stage (string) optional

ID element. Usually used to indicate role, e.g. 'prod', 'staging', 'source', 'build', 'test', 'deploy', 'release'
Required: No

Default value: null

tags (map(string)) optional

Additional tags (e.g. {'BusinessUnit': 'XYZ'}).
Neither the tag keys nor the tag values will be modified by this module.

Required: No

Default value: { }

tenant (string) optional

ID element (Rarely used, not included by default). A customer identifier, indicating who this instance of a resource is for
Required: No

Default value: null

Outputs

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

Dependencies

Requirements

terraform, version: >= 1.3.0
aws, version: >= 4.9.0
postgresql, version: >= 1.17.1
random, version: >= 2.3

Providers

aws, version: >= 4.9.0
random, version: >= 2.3

Modules

Name	Version	Source	Description
`aurora_postgres_cluster`	1.3.2	`cloudposse/rds-cluster/aws`	https://www.terraform.io/docs/providers/aws/r/rds_cluster.html
`cluster`	0.25.0	`cloudposse/label/null`	n/a
`dns_gbl_delegated`	1.5.0	`cloudposse/stack-config/yaml//modules/remote-state`	n/a
`eks`	1.5.0	`cloudposse/stack-config/yaml//modules/remote-state`	n/a
`iam_roles`	latest	`../account-map/modules/iam-roles`	n/a
`kms_key_rds`	0.12.1	`cloudposse/kms-key/aws`	n/a
`parameter_store_write`	0.11.0	`cloudposse/ssm-parameter-store/aws`	n/a
`this`	0.25.0	`cloudposse/label/null`	n/a
`vpc`	1.5.0	`cloudposse/stack-config/yaml//modules/remote-state`	n/a
`vpc_ingress`	1.5.0	`cloudposse/stack-config/yaml//modules/remote-state`	n/a

Resources

The following resources are used by this module:

random_password.admin_password (resource)
random_pet.admin_user (resource)
random_pet.database_name (resource)

Data Sources

The following data sources are used by this module:

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)

References

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

Usage​

Finding Aurora Engine Version​

Examples​

Provisioned Aurora Postgres​

Serverless v1 Aurora Postgres​

Serverless v2 Aurora Postgres​

Variables​

Required Variables​

Optional Variables​

Context Variables​

Outputs​

Dependencies​

Requirements​

Providers​

Modules​

Resources​

Data Sources​

References​

Usage

Finding Aurora Engine Version

Examples

Provisioned Aurora Postgres

Serverless v1 Aurora Postgres

Serverless v2 Aurora Postgres

Variables

Required Variables

Optional Variables

Context Variables

Outputs

Dependencies

Requirements

Providers

Modules

Resources

Data Sources

References