Opensearch Managed Service try call report generate API

The issue you're experiencing with the OpenSearch Managed Service report generation API is likely related to authentication or network access policies. While the API endpoint you mentioned (api/reporting/generateReport) is generally available for OpenSearch, receiving a 401 error suggests there might be some configuration issues preventing successful access.

Here are a few things to consider:

1. Authentication: Even though you're using a full access internal user, make sure this user has the correct permissions to access the reporting API. The 401 error indicates an unauthorized access attempt.

2. Network Policy: If you're using OpenSearch Serverless, check your network policy settings. A 401 error can occur when the network policy denies access to the OpenSearch Serverless APIs.

3. Public vs. Private Access: If you're trying to access the API from outside the VPC, ensure that public access is enabled in your network policy. If it's not enabled, you'll need to access it through a VPC endpoint.

4. IAM Permissions: Verify that your IAM user or role has the necessary permissions to access the reporting API. You may need to include actions like 'aoss:APIAccessAll' in your IAM policy.

5. Request Signing: Ensure that your API request is correctly signed if you're using IAM authentication.

To troubleshoot further:

1. Double-check your network policy configuration.
2. Review your IAM permissions.
3. If possible, try accessing the OpenSearch dashboard first to ensure your authentication is working correctly.
4. Consider using AWS CLI or tools like curl or awscurl to test the endpoint access directly.

If the issue persists after checking these points, you may need to contact AWS support for further assistance, as there could be specific configurations or limitations in your OpenSearch Managed Service setup affecting API access.
Sources
Troubleshoot OpenSearch Serverless errors | AWS re:Post
Getting a 401 when trying to access OpenSearch serverless dashboard | AWS re:Post