Databases

The database secrets engine generates database credentials dynamically based on configured roles. It works with a number of different databases through a plugin interface. There are a number of built-in database types, and an exposed framework for running custom database types for extendability. This means that services that need to access a database no longer need to hardcode credentials: they can request them from Vault, and use Vault's leasing mechanism to more easily roll keys. These are referred to as "dynamic roles" or "dynamic secrets".

Since every service is accessing the database with unique credentials, it makes auditing much easier when questionable data access is discovered. You can track it down to the specific instance of a service based on the SQL username.

Vault makes use of its own internal revocation system to ensure that users become invalid within a reasonable time of the lease expiring.

Static Roles

The database secrets engine supports the concept of "static roles", which are a 1-to-1 mapping of Vault Roles to usernames in a database. The current password for the database user is stored and automatically rotated by Vault on a configurable period of time. This is in contrast to dynamic secrets, where a unique username and password pair are generated with each credential request. When credentials are requested for the Role, Vault returns the current password for the configured database user, allowing anyone with the proper Vault policies to have access to the user account in the database.

Setup

Most secrets engines must be configured in advance before they can perform their functions. These steps are usually completed by an operator or configuration management tool.

1. Enable the database secrets engine:

   $ 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-database \
       plugin_name="..." \
       connection_url="..." \
       allowed_roles="..." \
       username="..." \
       password="..." \
   

   It is highly recommended a user within the database is created specifically for Vault to use. This user will be used to manipulate dynamic and static users within the database. This user is called the "root" user within the documentation.

   Vault will use the user specified here to create/update/revoke database credentials. That user must have the appropriate permissions to perform actions upon other database users (create, update credentials, delete, etc.).

   This secrets engine can configure multiple database connections. For details on the specific configuration options, please see the database-specific documentation.

3. After configuring the root user, it is highly recommended you rotate that user's password such that the vault user is not accessible by any users other than Vault itself:

   $ vault write -force database/rotate-root/my-database
   

   When this is done, the password for the user specified in the previous step is no longer accessible. Because of this, it is highly recommended that a user is created specifically for Vault to use to manage database users.

4. Configure a role that maps a name in Vault to a set of creation statements to create the database credential:

   $ vault write database/roles/my-role \
       db_name=my-database \
       creation_statements="..." \
       default_ttl="1h" \
       max_ttl="24h"
   Success! Data written to: database/roles/my-role
   

   The {{username}} and {{password}} fields will be populated by the plugin with dynamically generated values. In some plugins the {{expiration}} field is also supported.

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           FSREZ1S0kFsZtLat-y94
   username           v-vaultuser-e2978cd0-ugp7iqI2hdlff5hfjylJ-1602537260
   

Database Capabilities

As of Vault 1.6, all databases support dynamic roles and static roles. All plugins except MongoDB Atlas support rotating the root user's credentials. MongoDB Atlas cannot support rotating the root user's credentials because it uses a public and private key pair to authenticate.

Custom Plugins

This secrets engine allows custom database types to be run through the exposed plugin interface. Please see the custom database plugin for more information.

Password Generation

Passwords are generated via Password Policies. Databases can optionally set a password policy for use across all roles for that database. In other words, each time you call vault write database/config/my-database you can specify a password policy for all roles using my-database. Each database has a default password policy defined as: 20 characters with at least 1 uppercase character, at least 1 lowercase character, at least 1 number, and at least 1 dash character.

You cannot specify a password policy on a specific role as the purpose of password policies is to adhere to password requirements of systems (such as a database), not making passwords for specific users.

The default password generation can be represented as the following password policy:

length = 20

rule "charset" {
    charset = "abcdefghijklmnopqrstuvwxyz"
    min-chars = 1
}
rule "charset" {
    charset = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    min-chars = 1
}
rule "charset" {
    charset = "0123456789"
    min-chars = 1
}
rule "charset" {
    charset = "-"
    min-chars = 1
}

Disable Character Escaping

As of Vault 1.10, you can now specify the option disable_escaping with a value of true in some secrets engines to prevent Vault from escaping special characters in the username and password fields. This is necessary for some alternate connection string formats, such as ADO with MSSQL or Azure SQL. See the databases secrets engine API docs and reference individual plugin documentation to determine support for this parameter.

For example, when the password contains URL-escaped characters like % or # they will remain as so instead of becoming %23 and %25 respectively.

$ vault write database/config/my-mssql-database \
plugin_name="mssql-database-plugin" \
connection_url='server=localhost;port=1433;user id={{username}};password={{password}};database=mydb;' \
username="root" \
password='your#Strong(!)Password%' \
disable_escaping="true"

Tutorial

Refer to the following step-by-step tutorials for more information:

• Secrets as a Service: Dynamic Secrets
• Database Root Credential Rotation
• Database Static Roles and Credential Rotation

API

The database secrets engine has a full HTTP API. Please see the Database secret secrets engine API for more details.