Thanks Tim. Yeah I was able to get it to work by pointing directly to the 
hdfs:// URL for the data we want to query. For our initial Impala experiments 
we should be able to proceed. Do you know if there’s a jira tracking the long 
term fix? (or is that going to continue to be Impala-77?). Based on our initial 
experiments, we might be open to helping out with the fix, we can chime in on 
the jira in the next couple of weeks as well.

Thanks,

-- Piyush


From: Tim Armstrong <[email protected]>
Reply-To: "[email protected]" <[email protected]>
Date: Monday, December 4, 2017 at 8:35 PM
To: "[email protected]" <[email protected]>
Subject: Re: Using Impala with a federated HDFS setup

Hi Piyush,
  You're right that we don't support ViewFileSystem at the moment. It looks 
like IMPALA-77 was resolved by failing more gracefully for viewfs.

I suspect it just needs some targeted code changes and testing - the logic for 
different filesystems is mostly the same with some tweaks. I'm not sure when 
this will happen - it will likely largely depend on when someone steps forward 
to do it.
I believe pointing directly to the hdfs:// URLs should work.
 - Tim

On Thu, Nov 30, 2017 at 11:39 AM, Piyush Narang 
<[email protected]<mailto:[email protected]>> wrote:
Hi folks,

Our company is looking to experiment with setting up Impala for some of our 
adhoc query workloads. I was working on setting up Impala to test things out 
and I ran into the following errors on startup, “Currently configured default 
filesystem: ViewFileSystem. fs.defaultFS (viewfs://root) is not supported.”. 
Noticed that this has been implemented as part of this jira: 
https://issues.apache.org/jira/browse/IMPALA-77<https://urldefense.proofpoint.com/v2/url?u=https-3A__issues.apache.org_jira_browse_IMPALA-2D77&d=DwMFaQ&c=nxfEpP1JWHVKAq835DW4mA&r=3Ka-O_qIfLiCDaGELmIN3BcChZatNdPOwe36odQXFYo&m=qT5IbyXEu2Sy58jS9NeuJSnIOLpbD0hRJb4qI6t5_IY&s=GMdxzTI4bDF8FUK-J5SzOIyWrzk-S6NsEH0rVKTHKLg&e=>.
 Is this still currently not on the Impala roadmap? Are there any possible 
workarounds for users with federated namenodes?

The data we want to query as of now resides in one namenode’s namespace. A 
potential workaround for us might be to just expose that hdfs:// mount point 
directly. Not sure if anyone’s tried this and what kinds of issues they’ve run 
into.

Thanks,
Piyush

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