How to authenticate

Authentication

Apache Gravitino supports three kinds of authentication mechanisms: simple, OAuth and Kerberos. If you don't enable authentication for your client and server explicitly, you will use user anonymous to access the server.

Simple mode

If the client sets the simple mode, it will use the value of environment variable GRAVITINO_USER as the user. If the environment variable GRAVITINO_USER in the client isn't set, the client uses the user logging in the machine that sends requests.

For the client side, users can enable simple mode by the following code:

GravitinoClient client = GravitinoClient.builder(uri)
    .withMetalake("metalake")
    .withSimpleAuth()
    .build();

Additionally, the username can be directly used as a parameter to create a client.

GravitinoClient client = GravitinoClient.builder(uri)
    .withMetalake("metalake")
    .withSimpleAuth("test_user_name")
    .build();

OAuth mode

Gravitino only supports external OAuth 2.0 servers. To enable OAuth mode, users should follow the steps below.

• First, users need to guarantee that the external correctly configured OAuth 2.0 server supports Bearer JWT.

• Then, on the server side, users should set gravitino.authenticators as oauth and give gravitino.authenticator.oauth.defaultSignKey, gravitino.authenticator.oauth.serverUri and gravitino.authenticator.oauth.tokenPath a proper value.

• Next, for the client side, users can enable OAuth mode by the following code:

DefaultOAuth2TokenProvider authDataProvider = DefaultOAuth2TokenProvider.builder()
    .withUri("oauth server uri")
    .withCredential("yy:xx")
    .withPath("oauth/token")
    .withScope("test")
    .build();

GravitinoClient client = GravitinoClient.builder(uri)
    .withMetalake("metalake")
    .withOAuth(authDataProvider)
    .build();

Kerberos mode

To enable Kerberos mode, users need to guarantee that the server and client have the correct Kerberos configuration. In the server side, users should set gravitino.authenticators as kerberos and give gravitino.authenticator.kerberos.principal and gravitino.authenticator.kerberos.keytab a proper value. For the client side, users can enable kerberos mode by the following code:

// Use keytab to create KerberosTokenProvider
KerberosTokenProvider provider = KerberosTokenProvider.builder()
        .withClientPrincipal(clientPrincipal)
        .withKeyTabFile(new File(keytabFile))
        .build();

// Use ticketCache to create KerberosTokenProvider
KerberosTokenProvider provider = KerberosTokenProvider.builder()
        .withClientPrincipal(clientPrincipal)
        .build();        

GravitinoClient client = GravitinoClient.builder(uri)
    .withMetalake("metalake")
    .withKerberosAuth(provider)
    .build();

info

Now Iceberg REST service doesn't support Kerberos authentication. The URI must use the hostname of server instead of IP.

Server configuration

Configuration item	Description	Default value	Required	Since version
gravitino.authenticator	It is deprecated since Gravitino 0.6.0. Please use gravitino.authenticators instead.	simple	No	0.3.0
gravitino.authenticators	The authenticators which Gravitino uses, setting as simple,oauth or kerberos. Multiple authenticators are separated by commas. If a request is supported by multiple authenticators simultaneously, the first authenticator will be used by default.	simple	No	0.6.0-incubating
gravitino.authenticator.oauth.serviceAudience	The audience name when Gravitino uses OAuth as the authenticator.	GravitinoServer	No	0.3.0
gravitino.authenticator.oauth.allowSkewSecs	The JWT allows skew seconds when Gravitino uses OAuth as the authenticator.	0	No	0.3.0
gravitino.authenticator.oauth.defaultSignKey	The signing key of JWT when Gravitino uses OAuth as the authenticator.	(none)	Yes if use oauth as the authenticator	0.3.0
gravitino.authenticator.oauth.signAlgorithmType	The signature algorithm when Gravitino uses OAuth as the authenticator.	RS256	No	0.3.0
gravitino.authenticator.oauth.serverUri	The URI of the default OAuth server.	(none)	Yes if use oauth as the authenticator	0.3.0
gravitino.authenticator.oauth.tokenPath	The path for token of the default OAuth server.	(none)	Yes if use oauth as the authenticator	0.3.0
gravitino.authenticator.kerberos.principal	Indicates the Kerberos principal to be used for HTTP endpoint. Principal should start with HTTP/.	(none)	Yes if use kerberos as the authenticator	0.4.0
gravitino.authenticator.kerberos.keytab	Location of the keytab file with the credentials for the principal.	(none)	Yes if use kerberos as the authenticator	0.4.0

The signature algorithms that Gravitino supports follows:

Name	Description
HS256	HMAC using SHA-25A
HS384	HMAC using SHA-384
HS512	HMAC using SHA-51
RS256	RSASSA-PKCS-v1_5 using SHA-256
RS384	RSASSA-PKCS-v1_5 using SHA-384
RS512	RSASSA-PKCS-v1_5 using SHA-512
ES256	ECDSA using P-256 and SHA-256
ES384	ECDSA using P-384 and SHA-384
ES512	ECDSA using P-521 and SHA-512
PS256	RSASSA-PSS using SHA-256 and MGF1 with SHA-256
PS384	RSASSA-PSS using SHA-384 and MGF1 with SHA-384
PS512	RSASSA-PSS using SHA-512 and MGF1 with SHA-512

Example

You can follow the steps to set up an OAuth mode Gravitino server.

1. Prerequisite

   You need to install the JDK8 and Docker.

2. Set up an external OAuth 2.0 server

   There is a sample-authorization-server based on spring-authorization-server. The image has registered client information in the external OAuth 2.0 server and its clientId is test, secret is test, scope is test.

 docker run -p 8177:8177 --name sample-auth-server -d datastrato/sample-authorization-server:0.3.0

3. Open the JWK URL of the Authorization server in the browser and you can get the JWK.

   

4. Convert the JWK to PEM. You can use the online tool or other tools.

   

5. Copy the public key and remove the character \n and you can get the default signing key of Gravitino server.

6. You can refer to the Configurations and append the configurations to the conf/gravitino.conf.

gravitino.authenticators = oauth
gravitino.authenticator.oauth.serviceAudience = test
gravitino.authenticator.oauth.defaultSignKey = <the default signing key>
gravitino.authenticator.oauth.tokenPath = /oauth2/token
gravitino.authenticator.oauth.serverUri = http://localhost:8177

7. Open the URL of Gravitino server and login in with clientId test, clientSecret test, and scope test.

   

8. You can also use the curl command to access Gravitino.

Get access token

curl --location --request POST 'http://127.0.0.1:8177/oauth2/token?grant_type=client_credentials&client_id=test&client_secret=test&scope=test'

Use the access token to request the Gravitino

curl -v -X GET -H "Accept: application/vnd.gravitino.v1+json" -H "Content-Type: application/json" -H "Authorization: Bearer <access_token>" http://localhost:8090/api/version