PostgreSQL database secrets engine

PostgreSQL is one of the supported plugins for the database secrets engine. This plugin generates database credentials dynamically based on configured roles for the PostgreSQL database, and also supports Static Roles.

See the database secrets engine docs for more information about setting up the database secrets engine.

The PostgreSQL secrets engine uses pgx, the same database library as the PostgreSQL storage backend. Connection string options, including SSL options, can be found in the pgx and PostgreSQL connection string documentation.

Capabilities

Setup

1. Enable the database secrets engine if it is not already enabled:

   $ vault secrets enable database
   Success! Enabled the database secrets engine at: database/
   

   By default, the secrets engine will enable at the name of the engine. To enable the secrets engine at a different path, use the -path argument.

2. Configure Vault with the proper plugin and connection information:

   $ vault write database/config/my-postgresql-database \
       plugin_name="postgresql-database-plugin" \
       allowed_roles="my-role" \
       connection_url="postgresql://{{username}}:{{password}}@localhost:5432/database-name" \
       username="vaultuser" \
       password="vaultpass" \
       password_authentication="scram-sha-256"
   

3. Configure a role that maps a name in Vault to an SQL statement to execute to create the database credential:

   $ vault write database/roles/my-role \
       db_name="my-postgresql-database" \
       creation_statements="CREATE ROLE \"{{name}}\" WITH LOGIN PASSWORD '{{password}}' VALID UNTIL '{{expiration}}'; \
           GRANT SELECT ON ALL TABLES IN SCHEMA public TO \"{{name}}\";" \
       default_ttl="1h" \
       max_ttl="24h"
   Success! Data written to: database/roles/my-role
   

Usage

After the secrets engine is configured and a user/machine has a Vault token with the proper permission, it can generate credentials.

1. Generate a new credential by reading from the /creds endpoint with the name of the role:

   $ vault read database/creds/my-role
   Key                Value
   ---                -----
   lease_id           database/creds/my-role/2f6a614c-4aa2-7b19-24b9-ad944a8d4de6
   lease_duration     1h
   lease_renewable    true
   password           SsnoaA-8Tv4t34f41baD
   username           v-vaultuse-my-role-x
   

API

The full list of configurable options can be seen in the PostgreSQL database plugin API page.

For more information on the database secrets engine's HTTP API please see the Database secrets engine API page.

Authenticating to Cloud DBs via IAM

Google Cloud

Aside from IAM roles denoted by Google's CloudSQL documentation, the following SQL privileges are needed by the service account's DB user for minimum functionality with Vault. Additional privileges may be needed depending on the SQL configured on the database roles.

-- Enable service account to create roles within DB
ALTER USER "<YOUR DB USERNAME>" WITH CREATEROLE;

Setup

1. Enable the database secrets engine if it is not already enabled:

   $ vault secrets enable database
   Success! Enabled the database secrets engine at: database/
   

   By default, the secrets engine will enable at the name of the engine. To enable the secrets engine at a different path, use the -path argument.

2. Configure Vault with the proper plugin and connection information. Here you can explicitly enable GCP IAM authentication and use Application Default Credentials to authenticate:

   $ vault write database/config/my-postgresql-database \
       plugin_name="postgresql-database-plugin" \
       allowed_roles="my-role" \
       connection_url="host=project:us-west1:mydb user=test-user@project.iam dbname=postgres sslmode=disable" \
       auth_type="gcp_iam"
   

   You can also configure the connection and authenticate by directly passing in the service account credentials as an encoded JSON string:

   $ vault write database/config/my-postgresql-database \
       plugin_name="postgresql-database-plugin" \
       allowed_roles="my-role" \
       connection_url="host=project:region:instance user=test-user@project.iam dbname=postgres sslmode=disable" \
       auth_type="gcp_iam" \
       service_account_json="@my_credentials.json"
   

Once the connection has been configured and IAM authentication is complete, the steps to set up a role and generate credentials are the same as the ones listed above.