postgres

Creates a postgres Aurora RDS database instance

This module creates a postgres Aurora RDS database instance. It is made in the private subnets automatically created during environment setup and so can only be accessed in the VPC or through some proxy (e.g. VPN).

Backups

Opta will provision your database with 7 days of automatic daily backups in the form of RDS snapshots. You can find them either programmatically via the aws cli, or through the AWS web console (they will be called system snapshots, and they have a different tab than the manual ones).

Performance and Scaling

You can modify the DB instance class with the field instance_class in the module configuration.

Storage scaling is automatically managed by AWS Aurora, see the official documentation.

To add replicas to an existing cluser, follow the official guide.

Restoring from Snapshot

Opta supports creating a new database not just from scratch, but from database snapshots you have in your desired account + region. To do this, simply set the restore_from_snapshot to the ARN of said snapshot you wish to restore from.

There is a big caveat: as Opta has no knowledge of the initial db setup from which the snapshot was created, we do not know what database name, username, or password the database would be created with– these will always be set to those of the original database. If you try to link this module to a k8s-service, the db name/username/password secrets will be set to UNKNOWN_SEE_ORIGINAL_DB. To overcome this limitation, please use opta secret update on the your k8s-service yaml to manually populate the secrets in with the original values.

NOTE: Do not remove the restore_from_snapshot input after creation, even if the snapshot is created as it will cause the database to recreate.

Adding to Global Database

Opta supports distributed databases via AWS' Aurora Global database. This subject is talked in detail in the multi-region section of the docs

There is a big caveat: as the execution of Opta has no knowledge of the initial db serving as the primary, we do not know what database name, username, or password the database would be created with– these will always be set to those of the original database. If you try to link this module to a k8s-service, the db name/username/password secrets will be set to UNKNOWN_SEE_PRIMARY_DB. To overcome this limitation, please use opta secret update on the your k8s-service yaml to manually populate the secrets in with the original values.

Linking

When linked to a k8s-service, it adds connection credentials to your container’s environment variables as:

  • {module_name}_db_user
  • {module_name}_db_password
  • {module_name}_db_name
  • {module_name}_db_host

In the modules reference example, the {module_name} would be replaced with rds.

The permission list can optionally have one entry which should be a map for renaming the default environment variable names to a user-defined value:

links:
  - db:
      - db_user: DBUSER
        db_host: DBHOST
        db_name: DBNAME
        db_password: DBPASS

If present, this map must have renames for all 4 fields.

These values are passed securely into your environment by using a kubernetes secret created by opta within your k8s-service’s isolated k8s namespace. These secrets are then passed as environment variables directly into your container. Take note that since opta’s AWS/EKS clusters always have the disk encryption enabled, your secret never touches an unencrypted disk. Furthermore, because of k8’s RBAC, no other opta-managed k8s service can access this instance of the creds as a k8s secret without manual override of the RBAC, nor can any other entities/users unless given “read secret” permission on this namespace.

To those with the permissions, you can view it via the following command (MANIFEST_NAME is the name field in your yaml):

kubectl get secrets -n MANIFEST_NAME secret -o yaml

Fields

Name Description Default Required
instance_class This is the RDS instance type used for the Aurora cluster instances. db.t3.medium False
engine_version The version of the database to use. 11.9 False
multi_az Enable read-write replication across different availability zones on the same reason (doubles the cost, but needed for compliance). Can be added and updated at a later date without need to recreate. False False
safety Add deletion protection to stop accidental db deletions False False
backup_retention_days How many days to keep the backup retention 7 False
extra_security_groups_ids Ids of extra AWS security groups to add to the database [] False
create_global_database Create an Aurora Global database with this db as the master/writer False False
existing_global_database_id ID of the Aurora global database to attach None False
database_name The name of the database to create. Follow naming conventions here app False
restore_from_snapshot The arn of the snapshot to “restore” this database from. None False

Outputs

Name Description
global_database_id The id of the global database, if created

Last modified May 23, 2022 : Docs for new release (#191) (ba6432d)