## Preflight checks for Iceberg

URL: https://docs.atlan.com/apps/connectors/data-lakehouses/iceberg/references/preflight-checks-for-iceberg

> Technical validations performed before crawling Iceberg data lakehouse resources.

Before [crawling Iceberg](https://docs.atlan.com/llms/connectors/iceberg/crawl-iceberg/llms.txt), you can run [preflight checks](https://docs.atlan.com/llms/catalog/connector-capabilities/what-are-preflight-checks/llms.txt) to check for any permissions or configuration issues before running the crawler. The following preflight checks are performed:

## Authentication check

This check verifies that the provided credentials (REST catalog URI and token if required) are valid by attempting to connect to the Iceberg catalog and list namespaces.

✅ Authentication successful

❌ Authentication failed: `<error-message>`

## Catalog permissions check

This check verifies that the authenticated connection has the necessary permissions to access the catalog and list tables within namespaces.

✅ Catalog permissions successful

❌ Catalog permissions insufficient: `<error-message>`

Common failure reasons include:
* Insufficient scope permissions
* Catalog not found or inaccessible
* Network connectivity issues
* Invalid warehouse configuration

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