Spring Cloud Vault

	Note
	Copies of this document may be made for your own use and for distribution to others, provided that you do not charge any fee for such copies and further provided that each copy contains this Copyright Notice, whether distributed in print or electronically.

Spring Cloud Vault Config provides client-side support for externalized configuration in a distributed system. With HashiCorp’s Vault you have a central place to manage external secret properties for applications across all environments. Vault can manage static and dynamic secrets such as username/password for remote applications/resources and provide credentials for external services such as MySQL, PostgreSQL, Apache Cassandra, MongoDB, Consul, AWS and more.

1. Quick Start

Prerequisites

To get started with Vault and this guide you need a *NIX-like operating systems that provides:

wget, openssl and unzip
at least Java 7 and a properly configured JAVA_HOME environment variable

Install Vault

$ src/test/bash/install_vault.sh

Create SSL certificates for Vault

$ src/test/bash/create_certificates.sh

	Note
	`create_certificates.sh` creates certificates in `work/ca` and a JKS truststore `work/keystore.jks`. If you want to run Spring Cloud Vault using this quickstart guide you need to configure the truststore the `spring.cloud.vault.ssl.trust-store` property to `file:work/keystore.jks`.

Start Vault server

$ src/test/bash/local_run_vault.sh

Vault is started listening on 0.0.0.0:8200 using the inmem storage and https. Vault is sealed and not initialized when starting up.

	Note
	If you want to run tests, leave Vault uninitialized. The tests will initialize Vault and create a root token `00000000-0000-0000-0000-000000000000`.

If you want to use Vault for your application or give it a try then you need to initialize it first.

$ export VAULT_ADDR="https://localhost:8200"
$ export VAULT_SKIP_VERIFY=true # Don't do this for production
$ vault init

You should see something like:

Key 1: 7149c6a2e16b8833f6eb1e76df03e47f6113a3288b3093faf5033d44f0e70fe701
Key 2: 901c534c7988c18c20435a85213c683bdcf0efcd82e38e2893779f152978c18c02
Key 3: 03ff3948575b1165a20c20ee7c3e6edf04f4cdbe0e82dbff5be49c63f98bc03a03
Key 4: 216ae5cc3ddaf93ceb8e1d15bb9fc3176653f5b738f5f3d1ee00cd7dccbe926e04
Key 5: b2898fc8130929d569c1677ee69dc5f3be57d7c4b494a6062693ce0b1c4d93d805
Initial Root Token: 19aefa97-cccc-bbbb-aaaa-225940e63d76

Vault initialized with 5 keys and a key threshold of 3. Please
securely distribute the above keys. When the Vault is re-sealed,
restarted, or stopped, you must provide at least 3 of these keys
to unseal it again.

Vault does not store the master key. Without at least 3 keys,
your Vault will remain permanently sealed.

Vault will initialize and return a set of unsealing keys and the root token. Pick 3 keys and unseal Vault. Store the Vault token in the VAULT_TOKEN environment variable.

$ vault unseal (Key 1)
$ vault unseal (Key 2)
$ vault unseal (Key 3)
$ export VAULT_TOKEN=(Root token)
# Required to run Spring Cloud Vault tests after manual initialization
$ vault token-create -id="00000000-0000-0000-0000-000000000000" -policy="root"

Spring Cloud Vault accesses different resources. By default, the secret backend is enabled which accesses secret config settings via JSON endpoints.

The HTTP service has resources in the form:

/secret/{application}/{profile}
/secret/{application}
/secret/{defaultContext}/{profile}
/secret/{defaultContext}

where the "application" is injected as the spring.application.name in the SpringApplication (i.e. what is normally "application" in a regular Spring Boot app), "profile" is an active profile (or comma-separated list of properties). Properties retrieved from Vault will be used "as-is" without further prefixing of the property names.

2. Client Side Usage

To use these features in an application, just build it as a Spring Boot application that depends on spring-cloud-vault-config (e.g. see the test cases). Example Maven configuration:

Example 2.1. pom.xml

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.4.RELEASE</version>
    <relativePath /> <!-- lookup parent from repository -->
</parent>

<dependencies>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-vault-config</artifactId>
        <version>1.1.0.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>

<!-- repositories also needed for snapshots and milestones -->

Then you can create a standard Spring Boot application, like this simple HTTP server:

@SpringBootApplication
@RestController
public class Application {

    @RequestMapping("/")
    public String home() {
        return "Hello World!";
    }

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

When it runs it will pick up the external configuration from the default local Vault server on port 8200 if it is running. To modify the startup behavior you can change the location of the Vault server using bootstrap.properties (like application.properties but for the bootstrap phase of an application context), e.g.

Example 2.2. bootstrap.yml

spring.cloud.vault:
    host: localhost
    port: 8200
    scheme: https
    uri: https://localhost:8200
    connection-timeout: 5000
    read-timeout: 15000
    config:
        order: -10

host sets the hostname of the Vault host. The host name will be used for SSL certificate validation
port sets the Vault port
scheme setting the scheme to http will use plain HTTP. Supported schemes are http and https.
uri configure the Vault endpoint with an URI. Takes precedence over host/port/scheme configuration
connection-timeout sets the connection timeout in milliseconds
read-timeout sets the read timeout in milliseconds
config.order sets the order for the property source

Enabling further integrations requires additional dependencies and configuration. Depending on how you have set up Vault you might need additional configuration like SSL and authentication.

If the application imports the spring-boot-starter-actuator project, the status of the vault server will be available via the /health endpoint.

The vault health indicator can be enabled or disabled through the property health.vault.enabled (default true).

2.1 Authentication

Vault requires an authentication mechanism to authorize client requests.

Spring Cloud Vault supports multiple authentication mechanisms to authenticate applications with Vault.

For a quickstart, use the root token printed by the Vault initialization.

Example 2.3. bootstrap.yml

spring.cloud.vault:
    token: 19aefa97-cccc-bbbb-aaaa-225940e63d76

	Warning
	Consider carefully your security requirements. Static token authentication is fine if you want quickly get started with Vault, but a static token is not protected any further. Any disclosure to unintended parties allows Vault use with the associated token roles.

3. Authentication methods

Different organizations have different requirements for security and authentication. Vault reflects that need by shipping multiple authentication methods. Spring Cloud Vault supports token and AppId authentication.

3.1 Token authentication

Tokens are the core method for authentication within Vault. Token authentication requires a static token to be provided using the Bootstrap Application Context.

	Note
	Token authentication is the default authentication method. If a token is disclosed an unintended party gains access to Vault and can access secrets for the intended client.

Example 3.1. bootstrap.yml

spring.cloud.vault:
    authentication: TOKEN
    token: 00000000-0000-0000-0000-000000000000

authentication setting this value to TOKEN selects the Token authentication method
token sets the static token to use

3.2 AppId authentication

Vault supports AppId authentication that consists of two hard to guess tokens. The AppId defaults to spring.application.name that is statically configured. The second token is the UserId which is a part determined by the application, usually related to the runtime environment. IP address, Mac address or a Docker container name are good examples. Spring Cloud Vault Config supports IP address, Mac address and static UserId’s (e.g. supplied via System properties). The IP and Mac address are represented as Hex-encoded SHA256 hash.

IP address-based UserId’s use the local host’s IP address.

Example 3.2. bootstrap.yml using SHA256 IP-Address UserId’s

spring.cloud.vault:
    authentication: APPID
    app-id:
        user-id: IP_ADDRESS

authentication setting this value to APPID selects the AppId authentication method
app-id-path sets the path of the AppId mount to use
user-id sets the UserId method. Possible values are IP_ADDRESS, MAC_ADDRESS or a class name implementing a custom AppIdUserIdMechanism

The corresponding command to generate the IP address UserId from a command line is:

$ echo -n 192.168.99.1 | sha256sum

	Note
	Including the line break of `echo` leads to a different hash value so make sure to include the `-n` flag.

Mac address-based UserId’s obtain their network device from the localhost-bound device. The configuration also allows specifying a network-interface hint to pick the right device. The value of network-interface is optional and can be either an interface name or interface index (0-based).

Example 3.3. bootstrap.yml using SHA256 Mac-Address UserId’s

spring.cloud.vault:
    authentication: APPID
    app-id:
        user-id: MAC_ADDRESS
        network-interface: eth0

network-interface sets network interface to obtain the physical address

The corresponding command to generate the IP address UserId from a command line is:

$ echo -n 0AFEDE1234AC | sha256sum

	Note
	The Mac address is specified uppercase and without colons. Including the line break of `echo` leads to a different hash value so make sure to include the `-n` flag.

3.2.1 Custom UserId

The UserId generation is an open mechanism. You can set spring.cloud.vault.app-id.user-id to any string and the configured value will be used as static UserId.

A more advanced approach lets you set spring.cloud.vault.app-id.user-id to a classname. This class must be on your classpath and must implement the org.springframework.cloud.vault.AppIdUserIdMechanism interface and the createUserId method. Spring Cloud Vault will obtain the UserId by calling createUserId each time it authenticates using AppId to obtain a token.

Example 3.4. bootstrap.yml

spring.cloud.vault:
    authentication: APPID
    app-id:
        user-id: com.examlple.MyUserIdMechanism

Example 3.5. MyUserIdMechanism.java

public class MyUserIdMechanism implements AppIdUserIdMechanism {

  @Override
  public String createUserId() {
    String userId = ...
    return userId;
  }
}

3.3 AppRole authentication

AppRole is intended for machine authentication, like the deprecated (since Vault 0.6.1) Section 3.2, “AppId authentication”. AppRole authentication consists of two hard to guess (secret) tokens: RoleId and SecretId.

Spring Vault supports AppRole authentication by providing either RoleId only or together with a provided SecretId (push or pull mode).

RoleId and optionally SecretId must be provided by configuration, Spring Vault will not look up these or create a custom SecretId.

Example 3.6. bootstrap.yml with AppRole authentication properties

spring.cloud.vault:
    authentication: APPROLE
    app-role:
        role-id: bde2076b-cccb-3cf0-d57e-bca7b1e83a52

role-id sets the RoleId.

Example 3.7. bootstrap.yml with all AppRole authentication properties

spring.cloud.vault:
    authentication: APPROLE
    app-role:
        role-id: bde2076b-cccb-3cf0-d57e-bca7b1e83a52
        secret-id: 1696536f-1976-73b1-b241-0b4213908d39
        app-auth-path: approle

role-id sets the RoleId.
secret-id sets the SecretId. SecretId can be omitted if AppRole is configured without requiring SecretId (See bind_secret_id)
approle-path sets the path of the approle authentication mount to use

3.4 AWS-EC2 authentication

The aws-ec2 auth backend provides a secure introduction mechanism for AWS EC2 instances, allowing automated retrieval of a Vault token. Unlike most Vault authentication backends, this backend does not require first-deploying, or provisioning security-sensitive credentials (tokens, username/password, client certificates, etc.). Instead, it treats AWS as a Trusted Third Party and uses the cryptographically signed dynamic metadata information that uniquely represents each EC2 instance.

Example 3.8. bootstrap.yml using AWS-EC2 Authentication

spring.cloud.vault:
    authentication: AWS_EC2

AWS-EC2 authentication enables nonce by default to follow the Trust On First Use (TOFU) principle. Any unintended party that gains access to the PKCS#7 identity metadata can authenticate against Vault.

During the first login, Spring Cloud Vault generates a nonce that is stored in the auth backend aside the instance Id. Re-authentication requires the same nonce to be sent. Any other party does not have the nonce and can raise an alert in Vault for further investigation.

The nonce is kept in memory and is lost during application restart. You can configure a static nonce with spring.cloud.vault.aws-ec2.nonce.

AWS-EC2 authentication roles are optional and default to the AMI. You can configure the authentication role by setting the spring.cloud.vault.aws-ec2.role property.

Example 3.9. bootstrap.yml with configured role

spring.cloud.vault:
    authentication: AWS_EC2
    aws-ec2:
        role: application-server

Example 3.10. bootstrap.yml with all AWS EC2 authentication properties

spring.cloud.vault:
    authentication: AWS_EC2
    aws-ec2:
        role: application-server
        aws-ec2-path: aws-ec2
        identity-document: http://...
        nonce: my-static-nonce

authentication setting this value to AWS_EC2 selects the AWS EC2 authentication method
role sets the name of the role against which the login is being attempted.
aws-ec2-path sets the path of the AWS EC2 mount to use
identity-document sets URL of the PKCS#7 AWS EC2 identity document
nonce used for AWS-EC2 authentication. An empty nonce defaults to nonce generation

3.5 AWS-IAM authentication

The aws backend provides a secure authentication mechanism for AWS IAM roles, allowing the automatic authentication with vault based on the current IAM role of the running application. Unlike most Vault authentication backends, this backend does not require first-deploying, or provisioning security-sensitive credentials (tokens, username/password, client certificates, etc.). Instead, it treats AWS as a Trusted Third Party and uses the 4 pieces of information signed by the caller with their IAM credentials to verify that the caller is indeed using that IAM role.

The current IAM role the application is running in is automatically calculated. If you are running your application on AWS ECS then the application will use the IAM role assigned to the ECS task of the running container. If you are running your application naked on top of an EC2 instance then the IAM role used will be the one assigned to the EC2 instance.

When using the AWS-IAM authentication you must create a role in Vault and assign it to your IAM role. An empty role defaults to the friendly name the current IAM role.

Example 3.11. bootstrap.yml with required AWS-IAM Authentication properties

spring.cloud.vault:
    authentication: AWS_IAM

Example 3.12. bootstrap.yml with all AWS-IAM Authentication properties

spring.cloud.vault:
    authentication: AWS_IAM
    aws-iam:
        role: my-dev-role
        aws-path: aws
        server-id: some.server.name

role sets the name of the role against which the login is being attempted. This should be bound to your IAM role. If one is not supplied then the friendly name of the current IAM user will be used as the vault role.
aws-path sets the path of the AWS mount to use
server-id sets the value to use for the X-Vault-AWS-IAM-Server-ID header preventing certain types of replay attacks.

AWS-IAM requires the AWS Java SDK dependency (com.amazonaws:aws-java-sdk-core) as the authentication implementation uses AWS SDK types for credentials and request signing.

3.6 TLS certificate authentication

The cert auth backend allows authentication using SSL/TLS client certificates that are either signed by a CA or self-signed.

To enable cert authentication you need to:

Use SSL, see Chapter 9, Vault Client SSL configuration
Configure a Java Keystore that contains the client certificate and the private key
Set the spring.cloud.vault.authentication to CERT

Example 3.13. bootstrap.yml

spring.cloud.vault:
    authentication: CERT
    ssl:
        key-store: classpath:keystore.jks
        key-store-password: changeit
        cert-auth-path: cert

3.7 Cubbyhole authentication

Cubbyhole authentication uses Vault primitives to provide a secured authentication workflow. Cubbyhole authentication uses tokens as primary login method. An ephemeral token is used to obtain a second, login VaultToken from Vault’s Cubbyhole secret backend. The login token is usually longer-lived and used to interact with Vault. The login token will be retrieved from a wrapped response stored at /cubbyhole/response.

Creating a wrapped token

	Note
	Response Wrapping for token creation requires Vault 0.6.0 or higher.

Example 3.14. Creating and storing tokens

$ vault token-create -wrap-ttl="10m"
Key                            Value
---                            -----
wrapping_token:                397ccb93-ff6c-b17b-9389-380b01ca2645
wrapping_token_ttl:            0h10m0s
wrapping_token_creation_time:  2016-09-18 20:29:48.652957077 +0200 CEST
wrapped_accessor:              46b6aebb-187f-932a-26d7-4f3d86a68319

Example 3.15. bootstrap.yml

spring.cloud.vault:
    authentication: CUBBYHOLE
    token: 397ccb93-ff6c-b17b-9389-380b01ca2645

3.8 Kubernetes authentication

Kubernetes authentication mechanism (since Vault 0.8.3) allows to authenticate with Vault using a Kubernetes Service Account Token. The authentication is role based and the role is bound to a service account name and a namespace.

A file containing a JWT token for a pod’s service account is automatically mounted at /var/run/secrets/kubernetes.io/serviceaccount/token.

Example 3.16. bootstrap.yml with all Kubernetes authentication properties

spring.cloud.vault:
    authentication: KUBERNETES
    kubernetes:
        role: my-dev-role
        service-account-token-file: /var/run/secrets/kubernetes.io/serviceaccount/token

role sets the Role.
service-account-token-file sets the location of the file containing the Kubernetes Service Account Token. Defaults to /var/run/secrets/kubernetes.io/serviceaccount/token.

4. Secret Backends

4.1 Generic Backend

Spring Cloud Vault supports at the basic level the generic secret backend. The generic secret backend allows storage of arbitrary values as key-value store. A single context can store one or many key-value tuples. Contexts can be organized hierarchically. Spring Cloud Vault allows using the Application name and a default context name (application) in combination with active profiles.

/secret/{application}/{profile}
/secret/{application}
/secret/{default-context}/{profile}
/secret/{default-context}

The application name is determined by the properties:

spring.cloud.vault.generic.application-name
spring.cloud.vault.application-name
spring.application.name

Secrets can be obtained from other folders within the generic backend by adding their paths to the application name, separated by commas. For example, given the application name usefulapp,mysql1,projectx/aws, each of these folders will be used:

/secret/usefulapp
/secret/mysql1
/secret/projectx/aws

Spring Cloud Vault adds all active profiles to the list of possible context paths. No active profiles will skip accessing contexts with a profile name.

Properties are exposed like they are stored (i.e. without additional prefixes).

spring.cloud.vault:
    generic:
        enabled: true
        backend: secret
        profile-separator: '/'
        default-context: application
        application-name: my-app

enabled setting this value to false disables the secret backend config usage
backend sets the path of the secret mount to use
default-context sets the context name used by all applications
application-name overrides the application name for use in the generic backend
profile-separator separates the profile name from the context in property sources with profiles

4.2 Consul

Spring Cloud Vault can obtain credentials for HashiCorp Consul. The Consul integration requires the spring-cloud-vault-config-consul dependency.

Example 4.1. pom.xml

<dependencies>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-vault-config-consul</artifactId>
        <version>1.1.0.RELEASE</version>
    </dependency>
</dependencies>

The integration can be enabled by setting spring.cloud.vault.consul.enabled=true (default false) and providing the role name with spring.cloud.vault.consul.role=….

The obtained token is stored in spring.cloud.consul.token so using Spring Cloud Consul can pick up the generated credentials without further configuration. You can configure the property name by setting spring.cloud.vault.consul.token-property.

spring.cloud.vault:
    consul:
        enabled: true
        role: readonly
        backend: consul
        token-property: spring.cloud.consul.token

enabled setting this value to true enables the Consul backend config usage
role sets the role name of the Consul role definition
backend sets the path of the Consul mount to use
token-property sets the property name in which the Consul ACL token is stored

4.3 RabbitMQ

Spring Cloud Vault can obtain credentials for RabbitMQ.

The RabbitMQ integration requires the spring-cloud-vault-config-rabbitmq dependency.

Example 4.2. pom.xml

<dependencies>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-vault-config-rabbitmq</artifactId>
        <version>1.1.0.RELEASE</version>
    </dependency>
</dependencies>

The integration can be enabled by setting spring.cloud.vault.rabbitmq.enabled=true (default false) and providing the role name with spring.cloud.vault.rabbitmq.role=….

Username and password are stored in spring.rabbitmq.username and spring.rabbitmq.password so using Spring Boot will pick up the generated credentials without further configuration. You can configure the property names by setting spring.cloud.vault.rabbitmq.username-property and spring.cloud.vault.rabbitmq.password-property.

spring.cloud.vault:
    rabbitmq:
        enabled: true
        role: readonly
        backend: rabbitmq
        username-property: spring.rabbitmq.username
        password-property: spring.rabbitmq.password

enabled setting this value to true enables the RabbitMQ backend config usage
role sets the role name of the RabbitMQ role definition
backend sets the path of the RabbitMQ mount to use
username-property sets the property name in which the RabbitMQ username is stored
password-property sets the property name in which the RabbitMQ password is stored

4.4 AWS

Spring Cloud Vault can obtain credentials for AWS.

The AWS integration requires the spring-cloud-vault-config-aws dependency.

Example 4.3. pom.xml

<dependencies>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-vault-config-aws</artifactId>
        <version>1.1.0.RELEASE</version>
    </dependency>
</dependencies>

The integration can be enabled by setting spring.cloud.vault.aws=true (default false) and providing the role name with spring.cloud.vault.aws.role=….

The access key and secret key are stored in cloud.aws.credentials.accessKey and cloud.aws.credentials.secretKey so using Spring Cloud AWS will pick up the generated credentials without further configuration. You can configure the property names by setting spring.cloud.vault.aws.access-key-property and spring.cloud.vault.aws.secret-key-property.

spring.cloud.vault:
    aws:
        enabled: true
        role: readonly
        backend: aws
        access-key-property: cloud.aws.credentials.accessKey
        secret-key-property: cloud.aws.credentials.secretKey

enabled setting this value to true enables the AWS backend config usage
role sets the role name of the AWS role definition
backend sets the path of the AWS mount to use
access-key-property sets the property name in which the AWS access key is stored
secret-key-property sets the property name in which the AWS secret key is stored

5. Database backends

Vault supports several database secret backends to generate database credentials dynamically based on configured roles. This means services that need to access a database no longer need to configure credentials: they can request them from Vault, and use Vault’s leasing mechanism to more easily roll keys.

Spring Cloud Vault integrates with these backends:

Section 5.1, “Apache Cassandra”
Section 5.2, “MongoDB”
Section 5.3, “MySQL”
Section 5.4, “PostgreSQL”

Using a database secret backend requires to enable the backend in the configuration and the spring-cloud-vault-config-databases dependency.

Vault ships since 0.7.1 with a dedicated database secret backend that allows database integration via plugins. You can use that specific backend by adapting one of the JDBC database properties above. Make sure to specify the appropriate backend path, e.g. spring.cloud.vault.mysql.role.backend=database.

Example 5.1. pom.xml

<dependencies>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-vault-config-databases</artifactId>
        <version>1.1.0.RELEASE</version>
    </dependency>
</dependencies>

	Note
	Enabling multiple JDBC-compliant databases will generate credentials and store them by default in the same property keys hence property names for JDBC secrets need to be configured separately.

5.1 Apache Cassandra

Spring Cloud Vault can obtain credentials for Apache Cassandra. The integration can be enabled by setting spring.cloud.vault.cassandra.enabled=true (default false) and providing the role name with spring.cloud.vault.cassandra.role=….

Username and password are stored in spring.data.cassandra.username and spring.data.cassandra.password so using Spring Boot will pick up the generated credentials without further configuration. You can configure the property names by setting spring.cloud.vault.cassandra.username-property and spring.cloud.vault.cassandra.password-property.

spring.cloud.vault:
    cassandra:
        enabled: true
        role: readonly
        backend: cassandra
        username-property: spring.data.cassandra.username
        password-property: spring.data.cassandra.username

enabled setting this value to true enables the Cassandra backend config usage
role sets the role name of the Cassandra role definition
backend sets the path of the Cassandra mount to use
username-property sets the property name in which the Cassandra username is stored
password-property sets the property name in which the Cassandra password is stored

5.2 MongoDB

Spring Cloud Vault can obtain credentials for MongoDB. The integration can be enabled by setting spring.cloud.vault.mongodb.enabled=true (default false) and providing the role name with spring.cloud.vault.mongodb.role=….

Username and password are stored in spring.data.mongodb.username and spring.data.mongodb.password so using Spring Boot will pick up the generated credentials without further configuration. You can configure the property names by setting spring.cloud.vault.mongodb.username-property and spring.cloud.vault.mongodb.password-property.

spring.cloud.vault:
    mongodb:
        enabled: true
        role: readonly
        backend: mongodb
        username-property: spring.data.mongodb.username
        password-property: spring.data.mongodb.password

enabled setting this value to true enables the MongodB backend config usage
role sets the role name of the MongoDB role definition
backend sets the path of the MongoDB mount to use
username-property sets the property name in which the MongoDB username is stored
password-property sets the property name in which the MongoDB password is stored

5.3 MySQL

Spring Cloud Vault can obtain credentials for MySQL. The integration can be enabled by setting spring.cloud.vault.mysql.enabled=true (default false) and providing the role name with spring.cloud.vault.mysql.role=….

Username and password are stored in spring.datasource.username and spring.datasource.password so using Spring Boot will pick up the generated credentials without further configuration. You can configure the property names by setting spring.cloud.vault.mysql.username-property and spring.cloud.vault.mysql.password-property.

spring.cloud.vault:
    mysql:
        enabled: true
        role: readonly
        backend: mysql
        username-property: spring.datasource.username
        password-property: spring.datasource.username

enabled setting this value to true enables the MySQL backend config usage
role sets the role name of the MySQL role definition
backend sets the path of the MySQL mount to use
username-property sets the property name in which the MySQL username is stored
password-property sets the property name in which the MySQL password is stored

5.4 PostgreSQL

Spring Cloud Vault can obtain credentials for PostgreSQL. The integration can be enabled by setting spring.cloud.vault.postgresql.enabled=true (default false) and providing the role name with spring.cloud.vault.postgresql.role=….

Username and password are stored in spring.datasource.username and spring.datasource.password so using Spring Boot will pick up the generated credentials without further configuration. You can configure the property names by setting spring.cloud.vault.postgresql.username-property and spring.cloud.vault.postgresql.password-property.

spring.cloud.vault:
    postgresql:
        enabled: true
        role: readonly
        backend: postgresql
        username-property: spring.datasource.username
        password-property: spring.datasource.username

enabled setting this value to true enables the PostgreSQL backend config usage
role sets the role name of the PostgreSQL role definition
backend sets the path of the PostgreSQL mount to use
username-property sets the property name in which the PostgreSQL username is stored
password-property sets the property name in which the PostgreSQL password is stored

6. Configure `PropertySourceLocator` behavior

Spring Cloud Vault uses property-based configuration to create PropertySources for generic and discovered secret backends.

Discovered backends provide VaultSecretBackendDescriptor beans to describe the configuration state to use secret backend as PropertySource. A SecretBackendMetadataFactory is required to create a SecretBackendMetadata object which contains path, name and property transformation configuration.

SecretBackendMetadata is used to back a particular PropertySource.

You can register an arbitrary number of beans implementing VaultConfigurer for customization. Default generic and discovered backend registration is disabled if Spring Cloud Vault discovers at least one VaultConfigurer bean. You can however enable default registration with SecretBackendConfigurer.registerDefaultGenericSecretBackends() and SecretBackendConfigurer.registerDefaultDiscoveredSecretBackends().

public class CustomizationBean implements VaultConfigurer {

    @Override
    public void addSecretBackends(SecretBackendConfigurer configurer) {

        configurer.add("secret/my-application");

        configurer.registerDefaultGenericSecretBackends(false);
        configurer.registerDefaultDiscoveredSecretBackends(true);
    }
}

	Note
	All customization is required to happen in the bootstrap context. Add your configuration classes to `META-INF/spring.factories` at `org.springframework.cloud.bootstrap.BootstrapConfiguration` in your application.

7. Service Registry Configuration

You can use a DiscoveryClient (such as from Spring Cloud Consul) to locate a Vault server by setting spring.cloud.vault.discovery.enabled=true (default false). The net result of that is that your apps need a bootstrap.yml (or an environment variable) with the appropriate discovery configuration. The benefit is that the Vault can change its co-ordinates, as long as the discovery service is a fixed point. The default service id is vault but you can change that on the client with spring.cloud.vault.discovery.serviceId.

The discovery client implementations all support some kind of metadata map (e.g. for Eureka we have eureka.instance.metadataMap). Some additional properties of the service may need to be configured in its service registration metadata so that clients can connect correctly. Service registries that do not provide details about transport layer security need to provide a scheme metadata entry to be set either to https or http. If no scheme is configured and the service is not exposed as secure service, then configuration defaults to spring.cloud.vault.scheme which is https when it’s not set.

spring.cloud.vault.discovery:
    enabled: true
    service-id: my-vault-service

8. Vault Client Fail Fast

In some cases, it may be desirable to fail startup of a service if it cannot connect to the Vault Server. If this is the desired behavior, set the bootstrap configuration property spring.cloud.vault.fail-fast=true and the client will halt with an Exception.

spring.cloud.vault:
    fail-fast: true

9. Vault Client SSL configuration

SSL can be configured declaratively by setting various properties. You can set either javax.net.ssl.trustStore to configure JVM-wide SSL settings or spring.cloud.vault.ssl.trust-store to set SSL settings only for Spring Cloud Vault Config.

spring.cloud.vault:
    ssl:
        trust-store: classpath:keystore.jks
        trust-store-password: changeit

trust-store sets the resource for the trust-store. SSL-secured Vault communication will validate the Vault SSL certificate with the specified trust-store.
trust-store-password sets the trust-store password

Please note that configuring spring.cloud.vault.ssl.* can be only applied when either Apache Http Components or the OkHttp client is on your class-path.

10. Lease lifecycle management (renewal and revocation)

With every secret, Vault creates a lease: metadata containing information such as a time duration, renewability, and more.

Vault promises that the data will be valid for the given duration, or Time To Live (TTL). Once the lease is expired, Vault can revoke the data, and the consumer of the secret can no longer be certain that it is valid.

Spring Cloud Vault maintains a lease lifecycle beyond the creation of login tokens and secrets. That said, login tokens and secrets associated with a lease are scheduled for renewal just before the lease expires until terminal expiry. Application shutdown revokes obtained login tokens and renewable leases.

Secret service and database backends (such as MongoDB or MySQL) usually generate a renewable lease so generated credentials will be disabled on application shutdown.

	Note
	Static tokens are not renewed or revoked.

Lease renewal and revocation is enabled by default and can be disabled by setting spring.cloud.vault.config.lifecycle.enabled to false. This is not recommended as leases can expire and Spring Cloud Vault cannot longer access Vault or services using generated credentials and valid credentials remain active after application shutdown.

spring.cloud.vault:
    config.lifecycle.enabled: true