Impala Connector | OpenMetadata SQL-on-Hadoop Integration

In this section, we provide guides and references to use the Impala connector. Configure and schedule Impala metadata and profiler workflows from the OpenMetadata UI:

• Requirements
• Metadata Ingestion
• Data Profiler
• Data Quality
• dbt Integration
• Enable Security
• Troubleshooting

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Requirements

Before configuring the Impala connector, make sure the following requirements are in place.

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Metadata

To extract metadata, the user needs to have privileges to perform SELECT, SHOW, and DESCRIBE operations on the databases and tables.

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Profiler & Data Quality

For profiler workflow and data quality tests, the user needs SELECT permission on the tables/schemas where the profiler/tests will be executed.

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Metadata Ingestion

To ingest metadata from Impala, you need to create a service connection. The service connects Impala with OpenMetadata. Once you create a service, OpenMetadata automatically starts ingesting metadata.

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Step 1: Add New Service

1. Navigate to Settings > Services.
2. Click Add New Service.

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Step 2: Select a Service and Connector

From the service type dropdown, select Database Services, then click the Impala connector tile.

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Step 3: Add Service Name and Description

• Enter a unique, descriptive Service Name. OpenMetadata identifies services by their service name. Enter a name that distinguishes this deployment from other Impala services you are ingesting metadata from.
• Optional: Enter a Description for the service.

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Step 4: Configure Connection Options

Specify your source credentials and verify the connection.

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Enter Connection Details

Enter the connection details for Impala. The right-hand panel in the UI displays inline help for each field.

• username: Specify the User to connect to Impala. It should have enough privileges to read all the metadata.
• password: Password to connect to Impala.
• hostPort: Enter the fully qualified hostname and port number for your Impala deployment in the Host and Port field.
• authMechanism: This parameter specifies the authentication method to use when connecting to the Impala server. Possible values are NOSASL, PLAIN, GSSAPI, LDAP, JWT. If you are using Kerberos authentication, you should set auth to GSSAPI.
• kerberosServiceName: This parameter specifies the Kerberos service name to use for authentication. This should only be specified if using Kerberos authentication.
• databaseSchema: Schema of the data source. This is optional parameter, if you would like to restrict the metadata reading to a single schema. When left blank, OpenMetadata Ingestion attempts to scan all the schemas.
• databaseName: In OpenMetadata, the Database Service hierarchy works as follows: Database Service > Database > Schema > Table. In the case of Impala, we won’t have a Database as such. If you’d like to see your data in a database named something other than default, you can specify the name in this field.
• useSSL: Establish secure connection with Impala. Enables SSL for the connector.
• authOptions: Enter the auth options string for impala connection.

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Test Connection

Once the credentials have been added, click on Test Connection and Save the changes.

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Step 5: Configure Ingestion Options

In the What to Ingest step, use filter patterns to control which assets OpenMetadata ingests from your database service. Filter patterns use regular expressions applied to asset names.

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How Filter Patterns Work

• Include: Add one or more comma-separated regular expressions. OpenMetadata ingests only assets whose names match at least one expression. Leave blank to include all assets.
• Exclude: Add one or more comma-separated regular expressions. OpenMetadata skips any asset whose name matches an expression. Leave blank to exclude nothing.

Rules match asset names using one of five expressions:

• contains: matches any name containing the value. For example, sales matches my_sales_data and sales_2024.
• starts with: matches names beginning with the value. For example, prod_ matches prod_db and prod_schema.
• ends with: matches names ending with the value. For example, _raw matches events_raw and logs_raw.
• is exactly: matches the exact name only. For example, analytics matches only analytics.
• matches regex: matches names using a regular expression. For example, ^prod_.*_v\d+$ matches prod_events_v1.

When both Include and Exclude are set, Exclude takes priority. Filter Options The Database, Schema, and Table sections each include the following filter options:

• Database: Controls which databases OpenMetadata ingests from the source.
• Schema: Controls which schemas within the ingested databases are included.
• Table: Controls which tables and views within the ingested schemas are included.

Each section provides the following controls:

• Scan Mode: You can choose between the following scan modes:
  • Scan all: Ingests every asset of that type the connector can access. This is the default.
  • Only specific: Enables include rules so only assets matching at least one rule are ingested.
• Exclude system toggle: Use this toggle to automatically filter out system-reserved names defined by the connector, for example, Exclude system databases for the Databases section.
• Always exclude: Add permanent exclusion rules (shown in red). Assets matching these rules are never ingested, regardless of include rules.
• Preview: Shows a real-time summary of what will be in scope based on your current rules.
• Include rules (available only in Only specific mode): Click + Add to define a rule. Added rules appear as chips; an asset is included if it matches any rule.

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Step 6: Create & Deploy

Click Create & Deploy to deploy the agent and start the first metadata ingestion run. OpenMetadata saves the service configuration and immediately begins pulling metadata from the source. To monitor ingestion progress or view the service you just added, go to Settings > Services and select your service.

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Configure Metadata Agent and Schedule Ingestion

The Metadata Agent extracts schemas, tables, columns, and other structural metadata from your source and keeps your OpenMetadata catalog in sync. It powers discovery, lineage, and governance across your data assets. When you click Create & Deploy, OpenMetadata automatically deploys a Metadata Agent for this service and triggers the first ingestion run. View its status and run history from the Agents tab on the service detail page. To configure the additional Metadata Agent and schedule ingestion, follow these steps:

1. Navigate to Settings > Services and select the service type.
2. Click the service you have added.
3. Select the Agents tab and click Add Agent > Metadata. For some services, the dropdown is not available and clicking Add Agent takes you directly to the agent configuration page.
4. On the Configure Ingestion page, do the following and click Next.
   • Name this Ingestion: Enter a unique recognizable name for this ingestion pipeline.
   • Agent Setup: Configure core parameters for metadata extraction. The following fields are available:

     Field	Default	Description
     Default Owner	—	Owner applied to all entities when no specific level owner is configured. Accepts a user or team name/email.
     Service Owner	—	Owner assigned to the service entity.
     Database Owner	—	Owner assigned to all ingested databases. Accepts a single owner or a per-database name mapping.
     Database Schema Owner	—	Owner assigned to all ingested schemas. Accepts a single owner or a per-schema name mapping.
     Table Owner	—	Owner assigned to all ingested tables. Accepts a single owner or a per-table name mapping.
     Enable Inheritance	On	When on, child entities inherit the owner from their parent when they have no owner configured.
     Query Log Duration	1	Number of days to look back in query logs when processing stored procedure results.
     Query Parsing Timeout Limit	300	Timeout in seconds for parsing a single query.
     Number of Threads	1	Number of threads to use for parallel table ingestion.
     Incremental Extraction	Off	When enabled, subsequent runs only extract entities changed since the last successful run.
     Successful Pipeline Run Lookback Days	7	Number of days to search back for a prior successful run to use as a baseline for incremental extraction.
     Safety Margin Days	1	Additional days added to the baseline timestamp as a buffer for incremental extraction.
     JSON Schema Sample Size	10	Number of rows sampled to infer JSON column schema. Only applies when Extract JSON Schema is enabled in Advanced Config.

     
   • Filter Patterns: Apply include or exclude rules to scope which databases, schemas, tables, and stored procedures this agent ingests. For more information about various filter options, see Step 6: Configure Ingestion Options.
   • Scope & Behaviour: Control how the agent handles metadata during ingestion. Toggle each option on or off based on your needs:

     Toggle	Default	Description
     Include Tables	On	Ingest table metadata from the source. Turn off to skip tables entirely.
     Include Tags	On	Ingest tags from the source.
     Include Stored Procedures	On	Ingest stored procedure metadata.
     Include DDL Statements	Off	Ingest DDL statements alongside table metadata.
     Include Owners	Off	Assign owners to ingested entities when the source owner’s email matches a user in OpenMetadata. Does not overwrite an existing owner.
     Include Custom Properties	Off	Ingest connector-specific custom properties onto entities.
     Mark Deleted Tables	On	Soft-delete tables in OpenMetadata when they are removed from the source. Applies only within the currently ingested schema.
     Mark Deleted Stored Procedures	On	Soft-delete stored procedures in OpenMetadata when they are removed from the source.
     Mark Deleted Schemas	Off	Soft-delete schemas and all their child assets when removed from the source.
     Mark Deleted Databases	Off	Soft-delete databases and all their child assets when removed from the source.
     Override Metadata	Off	When on, source values overwrite existing descriptions, tags, owners, and display names in OpenMetadata. When off, OpenMetadata only updates fields that have no existing value.
     Enable Debug Log	Off	Sets the ingestion log level to DEBUG. Useful for troubleshooting.

     Available toggles vary by connector. Stored procedure options only appear for connectors that support stored procedures.
     
   • Advanced Config: Optional connector-specific settings such as Include Views and Extract JSON Schema.
5. On the Schedule Interval page, set when the agent runs:
   • Schedule: Choose a preset interval (Hourly, Daily, Weekly, Monthly) or enter a custom cron expression.
   • On-Demand: No automatic schedule; trigger the agent manually when needed.
   
6. Click Add to deploy the agent.

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Securing Impala Connection with SSL in OpenMetadata

To configure SSL for secure connections between OpenMetadata and an Impala database, add the key use_ssl with a value of true to the connectionArguments to enable SSL. Additionally, include the key ca_cert with the path to the CA certificate file as its value. Ensure that the certificate file is accessible by the server, and if deploying via Docker or Kubernetes, update the CA certificate in the OpenMetadata server to reflect these changes.

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