AWS Glue Data Catalog

The AWS Glue Data Catalog is a metadata store that lets you store and share metadata in the AWS Cloud. In order to connect to the AWS Glue Data Catalog as a source, you must configure both your AWS and Dremio accounts.

Supported Formats

Dremio can query the data stored in S3 in file formats (including delimited, Excel (XLSX), and Parquet) and Apache Iceberg or Delta Lake table formats.

Configuring Your AWS Account

To allow Dremio to access the metadata store in your AWS Glue Data Catalog, you must configure your AWS account using one of the following authentication methods: project data credentials or data source credentials. Additionally, to enable Dremio to access the Data Catalog, you need to modify IAM permissions during configuration by attaching the IAM policy, which is provided after the authentication instructions.

Review each authentication method below and choose the one that best meets your needs.

Authentication Using Project Data Credentials

Use project data credentials to enable Dremio to access the Data Catalog using the IAM role that is associated with your Dremio project. This IAM role was created when you signed up for Dremio and is the default credential that is used to access all the sources in your project.

For this option, you will attach the IAM policy template to your Dremio project's IAM role that enables Dremio to access the AWS Glue Data Catalog.

For instructions to set up the policy and attach them to an IAM role, see Set up AWS IAM Permissions.

Authentication Using Data Source Credentials

Use data source credentials to access the AWS Glue Data Catalog using either a source-specific access key or an IAM role.

The project key/role assumes this source-specific role that you created to access the Data Catalog. To use source-specific credentials:

1. Create an IAM role/user and add policies to provide Dremio access to Data Catalog.
2. Modify the project key/role to grant it permissions to assume the source-specific role you created.

For steps on how to add IAM policies, see:

• Creating an IAM Role if you are using an IAM role.
• Creating an IAM User if you are using an IAM user.

IAM Policy Template for Accessing the AWS Glue Data Catalog

The following IAM policy contains the minimum policy requirements to allow Dremio Cloud to read and query the Data Catalog.

IAM policy template for AWS Glue Catalog

{
    "Version": "2012-10-17",
    "Statement": [
      # Allow Dremio to run the listed AWS Glue API operations.
      {
          "Effect": "Allow",
          "Action": [
              "glue:GetDatabase",
              "glue:GetDatabases",
              "glue:GetPartition",
              "glue:GetPartitions",
              "glue:GetTable",
              "glue:GetTableVersions",
              "glue:GetTables",
              "glue:GetConnection",
              "glue:GetConnections",
              "glue:GetDevEndpoint",
              "glue:GetDevEndpoints",
              "glue:GetUserDefinedFunction",
              "glue:GetUserDefinedFunctions",
              "glue:BatchGetPartition"
          ],
          "Resource": [
              "*"
            ]
        },
        # Allow Dremio to read and write files in a bucket.
        {
            "Effect": "Allow",
            "Action": [
                "s3:GetObject",
                "s3:PutObject"
            ],
            "Resource": [
                "arn:aws:s3:::aws-glue-*/*",
                "arn:aws:s3:::*/*aws-glue-*/*"
            ]
        },
        # Allow Dremio to access the Amazon S3 buckets or folders with names containing either the 'aws-glue-' or 'crawler-public' prefixes.
        {
            "Effect": "Allow",
            "Action": [
                "s3:GetObject"
            ],
            "Resource": [
                "arn:aws:s3:::crawler-public*",
                "arn:aws:s3:::aws-glue-*"
            ]
        },
        # Allow Dremio to create or delete tags in the Glue catalog.
        {
            "Effect": "Allow",
            "Action": [
                "ec2:CreateTags",
                "ec2:DeleteTags"
            ],
            "Condition": {
                "ForAllValues:StringEquals": {
                    "aws:TagKeys": [
                        "aws-glue-service-resource"
                    ]
                }
            },
            "Resource": [
                "arn:aws:ec2:*:*:network-interface/*",
                "arn:aws:ec2:*:*:security-group/*",
                "arn:aws:ec2:*:*:instance/*"
            ]
        }
    ]
}

Adding an AWS Glue Data Catalog

To add an AWS Glue Data Catalog to your project:

1. From the Datasets page, in the Data Lakes section, click (+) Add Source.

note

Alternatively, click Data Lakes to display all data lake sources. From the top-right of the page, click the Add Data Lake button.

2. In the Add Data Source dialog, under Metastores, click AWS Glue Data Catalog.

The New AWS Glue Data Catalog Source dialog box appears, which contains the following sections:

• General settings: required fields to add a Data Catalog
• Optional settings: Advanced Options, Refraction Refresh, Metadata, Privileges

Refer to the following for guidance on how to complete each section.

General

To add a Data Catalog:

1. In the Name field, enter a name for the Data Catalog you are connecting to. The name cannot include the following special characters: /, :, [, or ].

2. For AWS Region Selection, select the AWS Region from the drop-down menu list where the Data Catalog is located.

3. Under Authentication select your preferred authentication method:

   • Choose Project Data Credentials if you prefer to use the default credentials that allows access to all sources in your project. These credentials were added when you originally signed up for Dremio and created your project. For set up instructions using this method, see Project Data Credentials with Access Key/IAM Role.
   • Choose Data Source Credentials if you prefer to use credentials to access a specific source. These credentials are created as part of the source configuration set up. You can choose to set up these credentials using either an access key or with an IAM role.
     • To set up the credentials using an access key, see Data Source Credentials with Access Key.
     • To set up the credentials using an IAM role, see Data Source Credentials with IAM Role.

4. (Optional) To limit the databases that are accessible via Dremio, add one or more databases that you want to allow access to. By default, all databases in a Glue catalog are accessible. By adding allowed databases, you limit access to those databases only. Databases entered must be valid. Misspelled or non-existent databases will not appear in the resulting source. If you add or remove one or more databases from the list, access to them is revoked immediately after you click Save.

5. (Optional) To secure the connections between the Data Catalog and Dremio, tick the Encrypt connection checkbox.

Advanced Options

Click Advanced Options in the left menu sidebar -- all settings are optional.

Enable asynchronous access when possible

Activated by default, enables cloud caching for the Data Catalog while adding a new source or editing it. Clear the checkbox to deactivate asynchronous access.

Connection Properties

You can add key value pairs to provide custom connection properties relevant to the source.

1. Click Add Property.

2. For Name, enter a connection property.

3. For Value, enter the corresponding connection property value.

Lake Formation

Lake Formation provides access controls and allows administrators to define security policies. Enabling this functionality and additional details on the configuration options below are described in more detail on the Integrating with Lake Formation page.

• Enforce AWS Lake Formation access permissions on datasets. Dremio checks any datasets included in the Glue source for the required permissions to perform queries.
• Prefix to map Dremio users to AWS ARNs. Leave blank to default to the end user's username, or enter a REGEX expression.
• Prefix to map Dremio groups to AWS ARNs. Leave blank to default to the end user's group, or enter a REGEX expression.

Cache Options

Enable local caching when possible -- Selected by default, along with asynchronous access for cloud caching. Uncheck the checkbox to disable this option. For more information about local caching, see Columnar Cloud Cache.

Max percent of total available cache space to use when possible -- Specifies the disk quota, as a percentage, that a source can use on any single executor node only when local caching is enabled. The default is 100 percent of the total disk space available on the mount point provided for caching. You can either manually enter in a percentage in the value field or use the arrows to the far right to adjust the percentage.

Reflection Refresh

Click Reflection Refresh in the left menu sidebar. This section lets you manage how often reflections are refreshed and how long data can be served before expiration. To learn more about reflections, see Refreshing Reflections.

note

All reflection parameters are optional.

You can set the following refresh policies for reflections:

• Refresh period: Manage the refresh period by either enabling the option to never refresh or setting a refresh frequency in hours, days, or weeks. The default frequency to refresh reflections is every hour.
• Expiration period: Set the expiration period for the length of time that data can be served by either enabling the option to never expire or setting an expiration time in hours, days, or weeks. The default expiration time is set to three hours.

Metadata

Click Metadata in the left menu sidebar. This section lets you configure settings to refresh metadata and enable other dataset options.

note

All metadata parameters are optional.

You can configure Dataset Handling and Metadata Refresh parameters.

Dataset Handling

You can review each option provided in the following table to set up the dataset handling options to meet your needs.

Parameter	Description
Remove dataset definitions if underlying data is unavailable	By default, Dremio Cloud removes dataset definitions if underlying data is unavailable. This option is for scenarios when files are temporarily deleted and added back in the same location with new sets of files.

Metadata Refresh

The Metadata Refresh parameters include Dataset Discovery and Dataset Details.

• Dataset Discovery: The refresh interval for fetching top-level source object names such as databases and tables. Use this parameter to set the time interval.
  You can choose to set the frequency to fetch object names in minutes, hours, days, or weeks. The default frequency to fetch object names is 1 hour.

• Dataset Details: The metadata that Dremio needs for query planning such as information required for fields, types, shards, statistics, and locality. The following table describes the parameters that fetch the dataset information.

  Parameter	Description
  Fetch mode	You can choose to fetch only from queried datasets that are set by default. Dremio updates details for previously queried objects in a source. Fetching from all datasets is deprecated.
  Fetch every	You can choose to set the frequency to fetch dataset details in minutes, hours, days, or weeks. The default frequency to fetch dataset details is one hour.
  Expire after	You can choose to set the expiry time of dataset details in minutes, hours, days, or weeks. The default expiry time of dataset details is three hours.

Privileges

Click Privileges in the left menu sidebar. This section lets you grant privileges to specific users or roles. To learn more about how Dremio allows for the implementation of granular-level privileges, see Privileges.

note

All privileges parameters are optional.

To add a privilege for a user or to a role:

1. In the Add User/Role field, enter the user or role name that you want to apply privileges to.
2. Click Add to Privileges. The user or role is added to the Users table.

To set privileges for a user or to a role:

1. In the Users table, identify the user to set privileges for and click under the appropriate column (Select, Alter, Create Table, etc.) to either enable or disable that privilege. A green checkmark indicates that the privilege is enabled.
2. Click Save.

After you have connected Dremio to the AWS Glue Data Catalog, you’ll be able to edit the Data Catalog and remove it when it is no longer needed.

Editing the AWS Glue Data Catalog

To edit a Data Catalog source:

1. From the Datasets page, on the bottom-left of the page, click Data Lakes at the bottom-left of the page. A list of data lakes displays.
2. In the All Data Lakes section, under the Action column, hover over a data lake to display the hidden Settings (gear) icon, and click the icon > Edit Details.

note

Alternatively, you can click the name of the data lake, and, from the resulting data lake page, on the upper-right of the page, click the Settings (gear) icon.

3. In the Edit Source dialog box, General settings tab, you can update the Authentication credentials. Additionally, you can make changes to any of the optional settings, including Advanced Options, Reflection Refresh, Metadata, and Privileges. For information about these settings and guidance on the changes you can make, see Adding an AWS Glue Data Catalog.

note

In the General tab, you cannot change the name of the AWS Glue source.

4. Click Save.

Removing an AWS Glue Data Catalog Source

To remove a Data Catalog:

1. From the Datasets page, on the bottom-left of the page, click Data Lakes. A list of data lakes displays.
2. In the All Data Lakes section, under the Actions column, hover over a data lake to display the hidden Settings (gear) icon, and click the icon > Remove Source.
3. Confirm that you want to remove the source.

Limitations

• VPC-restricted S3 buckets are not supported.