Hive connector security configuration#

Overview#

The Hive connector supports both authentication and authorization.

Trino can impersonate the end user who is running a query. In the case of a user running a query from the command line interface, the end user is the username associated with the Trino CLI process or argument to the optional --user option.

Authentication can be configured with or without user impersonation on Kerberized Hadoop clusters.

Requirements#

End user authentication limited to Kerberized Hadoop clusters. Authentication user impersonation is available for both Kerberized and non-Kerberized clusters.

You must ensure that you meet the Kerberos, user impersonation and keytab requirements described in this section that apply to your configuration.

Kerberos#

In order to use the Hive connector with a Hadoop cluster that uses kerberos authentication, you must configure the connector to work with two services on the Hadoop cluster:

The Hive metastore Thrift service
The Hadoop Distributed File System (HDFS)

Access to these services by the Hive connector is configured in the properties file that contains the general Hive connector configuration.

Note

If your krb5.conf location is different from /etc/krb5.conf you must set it explicitly using the java.security.krb5.conf JVM property in jvm.config file.

Example: -Djava.security.krb5.conf=/example/path/krb5.conf.

Warning

Access to the Trino coordinator must be secured e.g., using Kerberos or password authentication, when using Kerberos authentication to Hadoop services. Failure to secure access to the Trino coordinator could result in unauthorized access to sensitive data on the Hadoop cluster. Refer to Security for further information.

See Kerberos authentication for information on setting up Kerberos authentication.

Keytab files#

Keytab files contain encryption keys that are used to authenticate principals to the Kerberos KDC. These encryption keys must be stored securely; you must take the same precautions to protect them that you take to protect ssh private keys.

In particular, access to keytab files must be limited to only the accounts that must use them to authenticate. In practice, this is the user that the Trino process runs as. The ownership and permissions on keytab files must be set to prevent other users from reading or modifying the files.

Keytab files must be distributed to every node running Trino. Under common deployment situations, the Hive connector configuration is the same on all nodes. This means that the keytab needs to be in the same location on every node.

You must ensure that the keytab files have the correct permissions on every node after distributing them.

Impersonation in Hadoop#

In order to use impersonation, the Hadoop cluster must be configured to allow the user or principal that Trino is running as to impersonate the users who log in to Trino. Impersonation in Hadoop is configured in the file core-site.xml. A complete description of the configuration options can be found in the Hadoop documentation.

Authentication#

The default security configuration of the Hive connector does not use authentication when connecting to a Hadoop cluster. All queries are executed as the user who runs the Trino process, regardless of which user submits the query.

The Hive connector provides additional security options to support Hadoop clusters that have been configured to use Kerberos.

When accessing HDFS, Trino can impersonate the end user who is running the query. This can be used with HDFS permissions and ACLs to provide additional security for data.

HDFS authentication#

In a Kerberized Hadoop cluster, Trino authenticates to HDFS using Kerberos. Kerberos authentication for HDFS is configured in the connector’s properties file using the following optional properties:

HDFS authentication properties#
Property value	Description	Default
`hive.hdfs.authentication.type`	HDFS authentication type; one of `NONE` or `KERBEROS`. When using the default value of `NONE`, Kerberos authentication is disabled, and no other properties must be configured. When set to `KERBEROS`, the Hive connector authenticates to HDFS using Kerberos.	`NONE`
`hive.hdfs.impersonation.enabled`	Enable HDFS end-user impersonation. Impersonating the end user can provide additional security when accessing HDFS if HDFS permissions or ACLs are used. HDFS Permissions and ACLs are explained in the HDFS Permissions Guide.	`false`
`hive.hdfs.trino.principal`	The Kerberos principal Trino uses when connecting to HDFS. Example: `trino-hdfs-superuser/trino-server-node@EXAMPLE.COM` or `trino-hdfs-superuser/_HOST@EXAMPLE.COM`. The `_HOST` placeholder can be used in this property value. When connecting to HDFS, the Hive connector substitutes in the hostname of the worker node Trino is running on. This is useful if each worker node has its own Kerberos principal.
`hive.hdfs.trino.keytab`	The path to the keytab file that contains a key for the principal specified by `hive.hdfs.trino.principal`. This file must be readable by the operating system user running Trino.
`hive.hdfs.wire-encryption.enabled`	Enable HDFS wire encryption. In a Kerberized Hadoop cluster that uses HDFS wire encryption, this must be set to `true` to enable Trino to access HDFS. Note that using wire encryption may impact query execution performance.

Configuration examples#

The following sections describe the configuration properties and values needed for the various authentication configurations with HDFS and the Hive connector.

Default `NONE` authentication without impersonation#

hive.hdfs.authentication.type=NONE

The default authentication type for HDFS is NONE. When the authentication type is NONE, Trino connects to HDFS using Hadoop’s simple authentication mechanism. Kerberos is not used.

`NONE` authentication with impersonation#

hive.hdfs.authentication.type=NONE
hive.hdfs.impersonation.enabled=true

When using NONE authentication with impersonation, Trino impersonates the user who is running the query when accessing HDFS. The user Trino is running as must be allowed to impersonate this user, as discussed in the section Impersonation in Hadoop. Kerberos is not used.

`KERBEROS` authentication without impersonation#

hive.hdfs.authentication.type=KERBEROS
hive.hdfs.trino.principal=hdfs@EXAMPLE.COM
hive.hdfs.trino.keytab=/etc/trino/hdfs.keytab

When the authentication type is KERBEROS, Trino accesses HDFS as the principal specified by the hive.hdfs.trino.principal property. Trino authenticates this principal using the keytab specified by the hive.hdfs.trino.keytab keytab.

Keytab files must be distributed to every node in the cluster that runs Trino.

Additional Information About Keytab Files.

`KERBEROS` authentication with impersonation#

hive.hdfs.authentication.type=KERBEROS
hive.hdfs.impersonation.enabled=true
hive.hdfs.trino.principal=trino@EXAMPLE.COM
hive.hdfs.trino.keytab=/etc/trino/hdfs.keytab

When using KERBEROS authentication with impersonation, Trino impersonates the user who is running the query when accessing HDFS. The principal specified by the hive.hdfs.trino.principal property must be allowed to impersonate the current Trino user, as discussed in the section Impersonation in Hadoop. Trino authenticates hive.hdfs.trino.principal using the keytab specified by hive.hdfs.trino.keytab.