open-vault/website/source/docs/secrets/mysql/index.html.md

layout	page_title	sidebar_current	description
docs	Secret Backend: MySQL	docs-secrets-mysql	The MySQL secret backend for Vault generates database credentials to access MySQL.

MySQL Secret Backend

Name: mysql

The MySQL secret backend for Vault generates database credentials dynamically based on configured roles. 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.

Additionally, it introduces a new ability: with every service 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.

This page will show a quick start for this backend. For detailed documentation on every path, use vault path-help after mounting the backend.

Quick Start

The first step to using the mysql backend is to mount it. Unlike the generic backend, the mysql backend is not mounted by default.

$ vault mount mysql
Successfully mounted 'mysql' at 'mysql'!

Next, we must configure Vault to know how to connect to the MySQL instance. This is done by providing a DSN (Data Source Name):

$ vault write mysql/config/connection \
    connection_url="root:root@tcp(192.168.33.10:3306)/"
Success! Data written to: mysql/config/connection

In this case, we've configured Vault with the user "root" and password "root, connecting to an instance at "192.168.33.10" on port 3306. It is not necessary that Vault has the root user, but the user must have privileges to create other users, namely the GRANT OPTION privilege.

For using UNIX socket use: root:root@unix(/path/to/socket)/.

Optionally, we can configure the lease settings for credentials generated by Vault. This is done by writing to the config/lease key:

$ vault write mysql/config/lease \
    lease=1h \
    lease_max=24h
Success! Data written to: mysql/config/lease

This restricts each credential to being valid or leased for 1 hour at a time, with a maximum use period of 24 hours. This forces an application to renew their credentials at least hourly, and to recycle them once per day.

The next step is to configure a role. A role is a logical name that maps to a policy used to generate those credentials. For example, lets create a "readonly" role:

$ vault write mysql/roles/readonly \
    sql="CREATE USER '{{name}}'@'%' IDENTIFIED BY '{{password}}';GRANT SELECT ON *.* TO '{{name}}'@'%';"
Success! Data written to: mysql/roles/readonly

By writing to the roles/readonly path we are defining the readonly role. This role will be created by evaluating the given sql statements. By default, the {{name}} and {{password}} fields will be populated by Vault with dynamically generated values. This SQL statement is creating the named user, and then granting it SELECT or read-only privileges to tables in the database. More complex GRANT queries can be used to customize the privileges of the role. See the MySQL manual for more information.

To generate a new set of credentials, we simply read from that role:

$ vault read mysql/creds/readonly
Key           	Value
lease_id      	mysql/creds/readonly/bd404e98-0f35-b378-269a-b7770ef01897
lease_duration	3600
password      	132ae3ef-5a64-7499-351e-bfe59f3a2a21
username      	readonly-aefa635a-18

By reading from the creds/readonly path, Vault has generated a new set of credentials using the readonly role configuration. Here we see the dynamically generated username and password, along with a one hour lease.

Using ACLs, it is possible to restrict using the mysql backend such that trusted operators can manage the role definitions, and both users and applications are restricted in the credentials they are allowed to read.

Optionally, you may configure both the number of characters from the role name that are truncated to form the display name portion of the mysql username interpolated into the {{name}} field: the default is 10.

You may also configure the total number of characters allowed in the entire generated username (the sum of the display name and uuid poritions); the default is 16. Note that versions of MySQL prior to 5.8 have a 16 character total limit on user names, so it is probably not safe to increase this above the default on versions prior to that.

API

/mysql/config/connection

POST

Description

Configures the connection DSN used to communicate with MySQL.

Method

POST

URL

`/mysql/config/connection`

Parameters

• connection_url required The MySQL DSN

• value optional

• max_open_connections optional Maximum number of open connections to the database. Defaults to 2.

• max_idle_connections optional Maximum number of idle connections to the database. A zero uses the value of `max_open_connections` and a negative value disables idle connections. If larger than `max_open_connections` it will be reduced to be equal.

• verify_connection optional If set, connection_url is verified by actually connecting to the database. Defaults to true.

Returns

A `204` response code.

/mysql/config/lease

POST

Description

Configures the lease settings for generated credentials. If not configured, leases default to 1 hour. This is a root protected endpoint.

Method

POST

URL

`/mysql/config/lease`

Parameters

• lease required The lease value provided as a string duration with time suffix. Hour is the largest suffix.
• lease_max required The maximum lease value provided as a string duration with time suffix. Hour is the largest suffix.

Returns

A `204` response code.

/mysql/roles/

POST

Description

Creates or updates the role definition.

Method

POST

URL

`/mysql/roles/`

Parameters

• sql required The SQL statements executed to create and configure a user. Must be a semicolon-separated string, a base64-encoded semicolon-separated string, a serialized JSON string array, or a base64-encoded serialized JSON string array. The '{{name}}' and '{{password}}' values will be substituted.
• revocation_sql optional The SQL statements executed to revoke a user. Must be a semicolon-separated string, a base64-encoded semicolon-separated string, a serialized JSON string array, or a base64-encoded serialized JSON string array. The '{{name}}' value will be substituted.
• rolename_length optional Determines how many characters from the role name will be used to form the mysql username interpolated into the '{{name}}' field of the sql parameter. The default is 4.
• displayname_length optional Determines how many characters from the token display name will be used to form the mysql username interpolated into the '{{name}}' field of the sql parameter. The default is 4.
• username_length optional Determines the maximum total length in characters of the mysql username interpolated into the '{{name}}' field of the sql parameter. The default is 16.

Returns

A `204` response code.

GET

Description

Queries the role definition.

Method

GET

URL

`/mysql/roles/`

Parameters

None

Returns

```javascript
{
  "data": {
    "sql": "CREATE USER..."
  }
}
```

LIST

Description

Returns a list of available roles. Only the role names are returned, not any values.

Method

LIST/GET

URL

`/mysql/roles` (LIST) or `/mysql/roles/?list=true` (GET)

Parameters

None

Returns

{
  "auth": null,
  "data": {
    "keys": ["dev", "prod"]
  },
  "lease_duration": 2764800,
  "lease_id": "",
  "renewable": false
}

DELETE

Description

Deletes the role definition.

Method

DELETE

URL

`/mysql/roles/`

Parameters

None

Returns

A `204` response code.

/mysql/creds/

GET

Description

Generates a new set of dynamic credentials based on the named role.

Method

GET

URL

`/mysql/creds/`

Parameters

None

Returns

```javascript
{
  "data": {
    "username": "user-role-aefa63",
    "password": "132ae3ef-5a64-7499-351e-bfe59f3a2a21"
  }
}
```