Hive connector with Amazon S3

The Hive connector can read and write tables that are stored in Amazon S3 or S3-compatible systems. This is accomplished by having a table or database location that uses an S3 prefix, rather than an HDFS prefix.

Trino uses its own S3 filesystem for the URI prefixes s3://, s3n:// and s3a://.

S3 configuration properties

Property name	Description
hive.s3.aws-access-key	Default AWS access key to use.
hive.s3.aws-secret-key	Default AWS secret key to use.
hive.s3.iam-role	IAM role to assume.
hive.s3.external-id	External ID for the IAM role trust policy.
hive.s3.endpoint	The S3 storage endpoint server. This can be used to connect to an S3-compatible storage system instead of AWS. When using v4 signatures, it is recommended to set this to the AWS region-specific endpoint (e.g., http[s]://s3.<AWS-region>.amazonaws.com).
hive.s3.region	Optional property to force the S3 client to connect to the specified region only.
hive.s3.storage-class	The S3 storage class to use when writing the data. Currently only STANDARD and INTELLIGENT_TIERING storage classes are supported. Default storage class is STANDARD
hive.s3.signer-type	Specify a different signer type for S3-compatible storage. Example: S3SignerType for v2 signer type
hive.s3.signer-class	Specify a different signer class for S3-compatible storage.
hive.s3.path-style-access	Use path-style access for all requests to the S3-compatible storage. This is for S3-compatible storage that doesn’t support virtual-hosted-style access, defaults to false.
hive.s3.staging-directory	Local staging directory for data written to S3. This defaults to the Java temporary directory specified by the JVM system property java.io.tmpdir.
hive.s3.pin-client-to-current-region	Pin S3 requests to the same region as the EC2 instance where Trino is running, defaults to false.
hive.s3.ssl.enabled	Use HTTPS to communicate with the S3 API, defaults to true.
hive.s3.sse.enabled	Use S3 server-side encryption, defaults to false.
hive.s3.sse.type	The type of key management for S3 server-side encryption. Use S3 for S3 managed or KMS for KMS-managed keys, defaults to S3.
hive.s3.sse.kms-key-id	The KMS Key ID to use for S3 server-side encryption with KMS-managed keys. If not set, the default key is used.
hive.s3.kms-key-id	If set, use S3 client-side encryption and use the AWS KMS to store encryption keys and use the value of this property as the KMS Key ID for newly created objects.
hive.s3.encryption-materials-provider	If set, use S3 client-side encryption and use the value of this property as the fully qualified name of a Java class which implements the AWS SDK’s EncryptionMaterialsProvider interface. If the class also implements Configurable from the Hadoop API, the Hadoop configuration will be passed in after the object has been created.
hive.s3.upload-acl-type	Canned ACL to use while uploading files to S3, defaults to PRIVATE. If the files are to be uploaded to an S3 bucket owned by a different AWS user, the canned ACL has to be set to one of the following: AUTHENTICATED_READ, AWS_EXEC_READ, BUCKET_OWNER_FULL_CONTROL, BUCKET_OWNER_READ, LOG_DELIVERY_WRITE, PUBLIC_READ, PUBLIC_READ_WRITE. Refer to the AWS canned ACL <https://docs.aws.amazon.com/emr/latest/ManagementGuide/emr-s3-acls.html>_ guide to understand each option’s definition.
hive.s3.skip-glacier-objects	Ignore Glacier objects rather than failing the query. This skips data that may be expected to be part of the table or partition. Defaults to false.
hive.s3.streaming.enabled	Use S3 multipart upload API to upload file in streaming way, without staging file to be created in the local file system.
hive.s3.streaming.part-size	The part size for S3 streaming upload. Defaults to 16MB.
hive.s3.proxy.host	Proxy host to use if connecting through a proxy.
hive.s3.proxy.port	Proxy port to use if connecting through a proxy.
hive.s3.proxy.protocol	Proxy protocol. HTTP or HTTPS , defaults to HTTPS.
hive.s3.proxy.non-proxy-hosts	Hosts list to access without going through the proxy.
hive.s3.proxy.username	Proxy user name to use if connecting through a proxy.
hive.s3.proxy.password	Proxy password to use if connecting through a proxy.
hive.s3.proxy.preemptive-basic-auth	Whether to attempt to authenticate preemptively against proxy when using base authorization, defaults to false.
hive.s3.sts.endpoint	Optional override for the sts endpoint given that IAM role based authentication via sts is used.
hive.s3.sts.region	Optional override for the sts region given that IAM role based authentication via sts is used.

S3 credentials

If you are running Trino on Amazon EC2, using EMR or another facility, it is recommended that you use IAM Roles for EC2 to govern access to S3. To enable this, your EC2 instances need to be assigned an IAM Role which grants appropriate access to the data stored in the S3 bucket(s) you wish to use. It is also possible to configure an IAM role with hive.s3.iam-role that is used for accessing any S3 bucket. This is much cleaner than setting AWS access and secret keys in the hive.s3.aws-access-key and hive.s3.aws-secret-key settings, and also allows EC2 to automatically rotate credentials on a regular basis without any additional work on your part.

Custom S3 credentials provider

You can configure a custom S3 credentials provider by setting the configuration property trino.s3.credentials-provider to the fully qualified class name of a custom AWS credentials provider implementation. The property must be set in the Hadoop configuration files referenced by the hive.config.resources Hive connector property.

The class must implement the AWSCredentialsProvider interface and provide a two-argument constructor that takes a java.net.URI and a Hadoop org.apache.hadoop.conf.Configuration as arguments. A custom credentials provider can be used to provide temporary credentials from STS (using STSSessionCredentialsProvider), IAM role-based credentials (using STSAssumeRoleSessionCredentialsProvider), or credentials for a specific use case (e.g., bucket/user specific credentials).

S3 security mapping

Trino supports flexible security mapping for S3, allowing for separate credentials or IAM roles for specific users or buckets/paths. The IAM role for a specific query can be selected from a list of allowed roles by providing it as an extra credential.

Each security mapping entry may specify one or more match criteria. If multiple criteria are specified, all criteria must match. Available match criteria:

• user: Regular expression to match against username. Example: alice|bob

• group: Regular expression to match against any of the groups that the user belongs to. Example: finance|sales

• prefix: S3 URL prefix. It can specify an entire bucket or a path within a bucket. The URL must start with s3:// but will also match s3a or s3n. Example: s3://bucket-name/abc/xyz/

The security mapping must provide one or more configuration settings:

• accessKey and secretKey: AWS access key and secret key. This overrides any globally configured credentials, such as access key or instance credentials.

• iamRole: IAM role to use if no user provided role is specified as an extra credential. This overrides any globally configured IAM role. This role is allowed to be specified as an extra credential, although specifying it explicitly has no effect, as it would be used anyway.

• roleSessionName: Optional role session name to use with iamRole. This can only be used when iamRole is specified. If roleSessionName includes the string ${USER}, then the ${USER} portion of the string will be replaced with the current session’s username. If roleSessionName is not specified, it defaults to trino-session.

• allowedIamRoles: IAM roles that are allowed to be specified as an extra credential. This is useful because a particular AWS account may have permissions to use many roles, but a specific user should only be allowed to use a subset of those roles.

• kmsKeyId: ID of KMS-managed key to be used for client-side encryption.

• allowedKmsKeyIds: KMS-managed key IDs that are allowed to be specified as an extra credential. If list cotains “*”, then any key can be specified via extra credential.

The security mapping entries are processed in the order listed in the configuration JSON. More specific mappings should thus be specified before less specific mappings. For example, the mapping list might have URL prefix s3://abc/xyz/ followed by s3://abc/ to allow different configuration for a specific path within a bucket than for other paths within the bucket. You can set default configuration by not including any match criteria for the last entry in the list.

In addition to the rules above, the default mapping can contain the optional useClusterDefault boolean property with the following behavior:

• false - (is set by default) property is ignored.

• true - This causes the default cluster role to be used as a fallback option. It can not be used with the following configuration properties:

  • accessKey

  • secretKey

  • iamRole

  • allowedIamRoles

If no mapping entry matches and no default is configured, the access is denied.

The configuration JSON can either be retrieved from a file or REST-endpoint specified via hive.s3.security-mapping.config-file.

Example JSON configuration:

{
  "mappings": [
    {
      "prefix": "s3://bucket-name/abc/",
      "iamRole": "arn:aws:iam::123456789101:role/test_path"
    },
    {
      "user": "bob|charlie",
      "iamRole": "arn:aws:iam::123456789101:role/test_default",
      "allowedIamRoles": [
        "arn:aws:iam::123456789101:role/test1",
        "arn:aws:iam::123456789101:role/test2",
        "arn:aws:iam::123456789101:role/test3"
      ]
    },
    {
      "prefix": "s3://special-bucket/",
      "accessKey": "AKIAxxxaccess",
      "secretKey": "iXbXxxxsecret"
    },
    {
      "prefix": "s3://encrypted-bucket/",
      "kmsKeyId": "kmsKey_10",
    },
    {
      "user": "test.*",
      "iamRole": "arn:aws:iam::123456789101:role/test_users"
    },
    {
      "group": "finance",
      "iamRole": "arn:aws:iam::123456789101:role/finance_users"
    },
    {
      "iamRole": "arn:aws:iam::123456789101:role/default"
    }
  ]
}

Property name	Description
hive.s3.security-mapping.config-file	The JSON configuration file or REST-endpoint URI containing security mappings.
hive.s3.security-mapping.json-pointer	A JSON pointer (RFC 6901) to mappings inside the JSON retrieved from the config file or REST-endpont. The whole document (“”) by default.
hive.s3.security-mapping.iam-role-credential-name	The name of the extra credential used to provide the IAM role.
hive.s3.security-mapping.kms-key-id-credential-name	The name of the extra credential used to provide the KMS-managed key ID.
hive.s3.security-mapping.refresh-period	How often to refresh the security mapping configuration.
hive.s3.security-mapping.colon-replacement	The character or characters to be used in place of the colon (:) character when specifying an IAM role name as an extra credential. Any instances of this replacement value in the extra credential value will be converted to a colon. Choose a value that is not used in any of your IAM ARNs.

Tuning properties

The following tuning properties affect the behavior of the client used by the Trino S3 filesystem when communicating with S3. Most of these parameters affect settings on the ClientConfiguration object associated with the AmazonS3Client.

Property name	Description	Default
hive.s3.max-error-retries	Maximum number of error retries, set on the S3 client.	10
hive.s3.max-client-retries	Maximum number of read attempts to retry.	5
hive.s3.max-backoff-time	Use exponential backoff starting at 1 second up to this maximum value when communicating with S3.	10 minutes
hive.s3.max-retry-time	Maximum time to retry communicating with S3.	10 minutes
hive.s3.connect-timeout	TCP connect timeout.	5 seconds
hive.s3.connect-ttl	TCP connect TTL, which affects connection reusage.	Connections do not expire.
hive.s3.socket-timeout	TCP socket read timeout.	5 seconds
hive.s3.max-connections	Maximum number of simultaneous open connections to S3.	500
hive.s3.multipart.min-file-size	Minimum file size before multi-part upload to S3 is used.	16 MB
hive.s3.multipart.min-part-size	Minimum multi-part upload part size.	5 MB

S3 data encryption

Trino supports reading and writing encrypted data in S3 using both server-side encryption with S3 managed keys and client-side encryption using either the Amazon KMS or a software plugin to manage AES encryption keys.

With S3 server-side encryption, called SSE-S3 in the Amazon documentation, the S3 infrastructure takes care of all encryption and decryption work. One exception is SSL to the client, assuming you have hive.s3.ssl.enabled set to true. S3 also manages all the encryption keys for you. To enable this, set hive.s3.sse.enabled to true.

With S3 client-side encryption, S3 stores encrypted data and the encryption keys are managed outside of the S3 infrastructure. Data is encrypted and decrypted by Trino instead of in the S3 infrastructure. In this case, encryption keys can be managed either by using the AWS KMS, or your own key management system. To use the AWS KMS for key management, set hive.s3.kms-key-id to the UUID of a KMS key. Your AWS credentials or EC2 IAM role will need to be granted permission to use the given key as well.

To use a custom encryption key management system, set hive.s3.encryption-materials-provider to the fully qualified name of a class which implements the EncryptionMaterialsProvider interface from the AWS Java SDK. This class has to be accessible to the Hive Connector through the classpath and must be able to communicate with your custom key management system. If this class also implements the org.apache.hadoop.conf.Configurable interface from the Hadoop Java API, then the Hadoop configuration is passed in after the object instance is created, and before it is asked to provision or retrieve any encryption keys.