[jira] [Created] (DRILL-6268) Drill-on-YARN client obtains HDFS URL incorrectly

["Paul Rogers (JIRA)" <ji...@apache.org>]

Paul Rogers created DRILL-6268:
----------------------------------

             Summary: Drill-on-YARN client obtains HDFS URL incorrectly
                 Key: DRILL-6268
                 URL: https://issues.apache.org/jira/browse/DRILL-6268
             Project: Apache Drill
          Issue Type: Bug
    Affects Versions: 1.13.0
            Reporter: Paul Rogers
             Fix For: 1.14.0


The Drill-on-YARN client must upload files to HDFS so that YARN can localize them. The code that does so is in {{DfsFacade}}. This code obtains the URL twice. The first time is correct:

{code}
  private void loadYarnConfig() {
    ...
      URI fsUri = FileSystem.getDefaultUri( yarnConf );
      if(fsUri.toString().startsWith("file:/")) {
        System.err.println("Warning: Default DFS URI is for a local file system: " + fsUri);
      }
    }
  }
{code}

The {{fsUri}} returned is {{hdfs://localhost:9000}}, which is the correct value for an out-of-the-box Hadoop 2.9.0 install after following [these instructions|https://hadoop.apache.org/docs/stable/hadoop-project-dist/hadoop-common/SingleCluster.html]. The instructions have the reader explicitly set the port number to 9000:

{code}
<configuration>
    <property>
        <name>fs.defaultFS</name>
        <value>hdfs://localhost:9000</value>
    </property>
</configuration>
{code}

The other place that gets the URL, this time or real, is {{DfsFacade.connect()}}:

{code}
    String dfsConnection = config.getString(DrillOnYarnConfig.DFS_CONNECTION);
{code}

This value comes back as {{hdfs://localhost/}}, which causes HDFS to try to connect on port 8020 (the Hadoop default), resulting in the following error:

{noformat}
Connecting to DFS... Connected.
Uploading /Users/paulrogers/bin/apache-drill-1.13.0.tar.gz to /users/drill/apache-drill-1.13.0.tar.gz ... Failed.
Failed to upload Drill archive
  Caused by: Failed to create DFS directory: /users/drill
  Caused by: Call From Pauls-MBP/192.168.1.243 to localhost:8020 failed on connection exception: java.net.ConnectException: Connection refused;
For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused
{noformat}

(Shout out here to [~arjun-kr] for suggesting we include the extra exception details; very helpful here.)

The workaround is to manually change the port to 8020 in the config setting shown above.

The full fix is to change the code to use the following line in {{connect()}}:

{code}
    String dfsConnection = FileSystem.getDefaultUri(yarnConf);
{code}

This bug is serious because it constrains the ability of users to select non-default HDFS ports.




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