Db2 Big SQL instance owner does not exist in the server that hosts the NameNode service causing Hadoop operations to fail

The Db2 Big SQL instance owner must exist in the server that hosts the NameNode service.

Symptoms

If the Db2 Big SQL instance owner does not exist in the NameNode server, then all operations on Hadoop tables fail.

Resolving the problem

It is possible that the Db2 Big SQL user might not exist in the NameNode service, if you enabled High Availability (HA) or moved the NameNode. You see errors in the Db2 Big SQL service when you try to run operations on Hadoop tables. For example, if you tried to run CREATE HADOOP TABLE t1 (c1 integer, c2 integer), you might see the following message:
The command was processed as an SQL statement 
because it was not a valid Command Line Processor command.
During SQL processing it returned: SQL5105N.  The statement failed
because a Db2 Big SQL component encountered an error.
...
Component returning the error:  "HIVE"...
The log file, /var/ibm/bigql/logs/bigsql.log might look like the following:
...
FAILED: SemanticException MetaException...Permission denied: 
user=bigsql, access=EXECUTE
...
To resolve this issue, use the Db2 Big SQL Head node to get the correct user ID. Then, create the bigsql user account in the NameNode server.
  1. In the terminal window of the Db2 Big SQL Head node, run the following command to get the correct user ID:
    id bigsql
    This command returns the UID, GID, and group information, such as shown in the following output:
    
    uid=2824(bigsql) gid=4456(hadoop) groups=4456(hadoop),100(users),487(hive)
  2. Open a terminal window in your NameNode server and run the following command to create the bigsql user account in the NameNode server:
    useradd -u 2824 -g hadoop -G hive bigsql