Using AWSGlue as Hive Metastore where data is in S3 - amazon-web-services

apologies if this has been answered elsewhere (but I don't think it has). I'm trying to use AWSGlue as an external metastore for Hive via an EMR cluster.
I have some data stored as text files on S3, and via the AWSGlue web console I created a table definition over those text files.
I also started up an EMR cluster following directions here: https://docs.aws.amazon.com/emr/latest/ReleaseGuide/emr-hive-metastore-glue.html
When I ssh into my EMR cluster and try to access Hive, I was expecting to find that the table I created in AWSGlue would exist when I ran a "show tables" command, but instead I get the following error message when starting the interactive Hive shell:
Exception in thread "main" java.lang.RuntimeException: java.lang.RuntimeException: org.apache.hadoop.hive.ql.metadata.HiveException: org.apache.hadoop.hive.ql.metadata.HiveException: MetaException(message:Unable to verify existence of default database: com.amazona ws.services.glue.model.AccessDeniedException: Please migrate your Catalog to enable access to this database (Service: AWSGlue; Statu s Code: 400; Error Code: AccessDeniedException; Request ID: e6b2a87b-fe5a-11e8-8ed4-5d1e42734679))
It seems like there's some permission error involved here. I'm using EMR_EC2_DefaultRole for my EC2 Instance Profile, so I didn't think this would happen.
Am I missing something obvious?
Thanks for any help you can provide!

Kindly attach AWS GLUE and S3 full access to you current IAM Role. that should do it.

In order to solve this issue, you will have to migrate your existing Athena catalog to Glue Data Catalog as explained here
To confirm your Athena catalog has been migrated, execute the following commands using the AWS cli:
aws glue get-catalog-import-status --catalog-id <aws-account-id> --region <region>

I have faced exactly same issue recently and able to get over it by upgrading Athena to Glue Catalog.
I am also not using Athena or Redshift Spectrum to query the table but on Glue and Athena consoles there was a message saying:
To use the AWS Glue Data Catalog as a common metadata repository for Amazon Athena, Amazon Redshift Spectrum, and Amazon EMR, you need to upgrade your Athena Data Catalog to the AWS Glue Data Catalog. Without the upgrade, tables and partitions created by AWS Glue cannot be queried with Amazon Athena or Redshift Spectrum.
Soon after upgrading I was able to query the table through hive and spark shells from EMR cluster.
This might be because your default and other databases are already created via Athena before and should be upgraded to Glue to be used from EMR as default is the default database that your hive will use after going to hive in EMR. You have to use DBName.tableName or explicitly switch to the DB that consists of your table to run queries.

Related

Connect Redshift Spectrum/ AWS EMR with Hudi directly or via AWS Glue Data Catalog

I'm trying to understand how to properly connect Redshift Spectrum with Hudi data.
Looks like I can directly create Redshift external table for data managed in Apache Hudi like it is described by the following documentation https://docs.aws.amazon.com/redshift/latest/dg/c-spectrum-external-tables.html The other way is to integrate Hudi with AWS Glue Data Catalog like it is mentioned here https://docs.aws.amazon.com/emr/latest/ReleaseGuide/emr-hudi-how-it-works.html and then access Hudi tables with Redshift Spectrum via AWS Glue Data Catalog.
The same needs I have for AWS EMR for Apache Spark. Looks like I may use Hudi directly from EMR or via AWS Glue Data Catalog.
Right now, I don't understand what way to choose. Could you please advise what is the benefit to use Hudi via AWS Glue Data Catalog, or do I need to use it directly from Redshift Spectrum and AWS EMR ?
Given that with Spark on EMR you need a catalog, Hive metastore if you will, then using the AWS Glue Catalog is an option.
If you elect to use Glue as metastore then use that as the source for all data. Unless errors are evident in which case use the Hudi api for Spark.

AWS Athena catalog other than Glue

It's known that AWS Athena comes integrated with AWS Glue for data catalog. Is there any way to configure Athena to use a different catalog e.g. to point to a different Hive metastore (e.g. on EC2 instances) managed by user?
Athena integration with a Hive Metastore is a new feature, now available in preview mode. You can find the details of how to use this feature in the documentation.

Why is my AWS Glue crawler not creating any tables?

I'm attempting to use AWS Glue to ETL a MySQL database in RDS to S3 so that I can work with the data in services like SageMaker or Athena. At this time, I don't care about transformations, this is a prototype and I simply want to dump the DB to S3 to start testing the various tool chains.
I've set up a Glue database and tested the connection to RDS successfully
I am using the AWS provide Glue IAM service role
My S3 bucket has the correct prefix of aws-glue-*
I created a crawler using the Glue database, AWSGlue service role, and S3 bucket above with the options:
Schema updates in the data store: Update the table definition in the data catalog
Object deletion in the data store: Delete tables and partitions from the data catalog.
When I run the crawler, it completes in ~60 seconds but it does not create any tables in the database.
I've tried adding the Admin policy to the glue service role to eliminate IAM access issues and the result is the same.
Also, CloudWatch logs are empty. Log groups are created for the test connection and the crawler but neither contains any entries.
I'm not sure how to further troubleshoot this, info on AWS Glue seems pretty sparse.
Figured it out. I had a syntax error in my "include path" for the crawler. Make sure the connection is the data source (RDS in this case) and the include path lists the data target you want e.g. mydatabase/% (I forgot the /%).
You can substitute the percent (%) character for a schema or table. For databases that support schemas, type MyDatabase/MySchema/% to match all tables in MySchema with MyDatabase. Oracle and MySQL don't support schema in the path, instead type MyDatabase/%. For information about which JDBC data stores support schema, see Cataloging Tables with a Crawler.
Ryan Fisher is correct in the sense that it's an error. I wouldn't categorize it as a syntax error. When I ran into this it was because the 'Include path' didn't include the default schema that sql server lovingly provides to you.
I had this: database_name/table_name
When it needed to be: database_name/dbo/table_name

HIVE_UNKNOWN_ERROR when running AWS Athena query on Glue table (RDS)

I'm getting an error when running an Athena query against a Glue table created from an RDS database:
HIVE_UNKNOWN_ERROR: Unable to create input format
The tables are created using a crawler. The tables show up correctly in the Glue interface:
However, they do not show up in the Athena interface under the database. It says: "The selected database has no tables"
I do not see this behaviour when using a database created using an S3 file. Maybe this is related to the error. Does anybody have an idea?
I had the same problem. This is the answer that I have got from AWS Support:
I understand that you set up a Glue crawler to crawl our RDS postresql database but the tables are not visible in Athena.
Athena service is designed to query tables that point to S3 as data-source. It cannot read data from non-S3 resources as of today.
So, unfortunately not possible at the moment.

How to connect AWS Athena to an exists Hive Metastore

I need to integrate AWS Athena service with an exists Hive Metastore (not AWS Glue).
Can you please let me know how can I connect Athena to Hive Metastore.
Athena works only with its own metastore or the related AWS Glue metastore. It will not work with an external metastore.
However, you can set up multiple tables or databases on the same underlying S3 storage. So if you wrote data to S3 using an external metastore, you could query those files with Athena, after setting up an appropriate database and table definition in Athena's metastore.
Amazon Athena just released a new feature (in preview now) that allows you to connect Athena to your Apache Hive Metastore. You can see the announcement here. Detailed steps to add the Hive Metastore connector are available in the Athena documentation.
Another way is to export the hive metadata to a file using the command
command="hive -f "+schema+"_tables.hql -S >> "+schema+".output"
where schema= to be exported and import the table definitions to Athena using groovy in python.
Instructions to set up groovy can be found in the link
https://github.com/aws-samples/aws-big-data-blog/tree/master/aws-blog-athena-importing-hive-metastores