Relational Database Service (RDS)

Get started with Relational Database Service (RDS) on LocalStack

LocalStack supports a basic version of the Relational Database Service (RDS) for testing.

Supported DB engines

Currently, it is possible to spin up PostgreSQL, MariaDB, MySQL, and MSSQL (SQL Server) databases on the local machine.

Postgres Engine

When creating an RDS DB cluster or instance with postgres/aurora-postgresql DB engine and a specific EngineVersion, LocalStack will install and provision the respective Postgres version on demand.

Currently, versions 11, 12, and 13 can be chosen - when selecting a major version outside of this range, the default version 11 is used as fallback.

Please be aware that the minor version cannot be freely selected - the latest available version will be installed in the docker environment.

In order to disable installation of custom versions, you may configure the environment variable RDS_PG_CUSTOM_VERSIONS=0, in which case always the default Postgres version 11 will be used.

MariaDB Engine

MariaDB will be installed as OS package in LocalStack. Currently, it is not possible to freely select a specific version.

Snapshots are currently not supported for MariaDB.

MySQL Engine

By default, a MariaDB installation is used when requesting a MySQL engine type.

If you wish to use a real MySQL version, you can do so by setting the environment variable RDS_MYSQL_DOCKER=1. With this feature enabled, MySQL community server will be started in a new docker container when requesting the MySQL engine. The engine-version will be used as the tag for the image, meaning you can freely select the desired MySQL version.

In case you want to use a special image, you can also set the environment variable MYSQL_IMAGE=<my-image:tag>.

Please note that the MasterUserPassword defined for the database cluster/instance will be used as the MYSQL_ROOT_PASSWORD environment for user root in the MySQL container. The user for MasterUserName will use the same password, and will have full access to the defined database.

DB Snapshots are currently not supported for MySQL.

MSSQL Engine

For the MSSQL engine, the database server is started in a new docker container using the latest image.

DB Snapshots are currently not supported for MSSQL.

End-to-end example (Postgres)

The local RDS service also supports the RDS Data API, which allows executing data queries against RDS clusters over a JSON/REST interface. Below is a simple example that illustrates (1) creation of an RDS cluster, (2) creation of a SecretsManager secret with the DB password, and (3) running a simple SELECT 123 query via the RDS Data API.

$ awslocal rds create-db-cluster --db-cluster-identifier db1 --engine aurora-postgresql --database-name test
    "DBCluster": {
        "Endpoint": "localhost:4510",
        "Port": 4510,  # may vary
        "DBClusterArn": "arn:aws:rds:us-east-1:000000000000:cluster:db1",

$ awslocal secretsmanager create-secret --name dbpass --secret-string test
    "ARN": "arn:aws:secretsmanager:eu-central-1:1234567890:secret:dbpass-cfnAX",
    "Name": "dbpass",
    "VersionId": "fffa1f4a-2381-4a2b-a977-4869d59a16c0"

$ awslocal rds-data execute-statement --database test --resource-arn arn:aws:rds:us-east-1:000000000000:cluster:db1 --secret-arn arn:aws:secretsmanager:eu-central-1:1234567890:secret:dbpass-cfnAX --include-result-metadata --sql 'SELECT 123'
    "columnMetadata": [
            "arrayBaseColumnType": 0,
            "isAutoIncrement": false,
            "isCaseSensitive": false,
            "isCurrency": false,
            "isSigned": true,
            "label": "?column?",
            "name": "?column?",
            "nullable": 0,
            "precision": 10,
            "scale": 0,
            "schemaName": "",
            "tableName": "",
            "type": 4,
            "typeName": "int4"
    "numberOfRecordsUpdated": 0,
    "records": [
                "longValue": 123

You can also use other clients like psql to interact with the database. The hostname and port of your created instance can be found in the output from above or by running awslocal rds describe-db-instances.

$ psql -d test -U test -p 4513 -h localhost -W
Password: <enter "test">

Default usernames and passwords

Please consider the following notes regarding default usernames/passwords and database names:

  • The default for master-username and db-name is “test”. The default master-user-password is “test” - except for MSSQL DBs, which uses “Test123!” as the default master password.
  • You can use any master-username, except “postgres”, for creating a new RDS instance. The user will automatically be created.
  • The user “postgres” is special, and it is not possible to create a new RDS instance with this user name.
  • Do not use db-name “postgres” as it is already in use by LocalStack.