Database Reference
In-Depth Information
Potential Errors
Here are some of the errors that can occur while you are configuring and installing Hue. The details of the errors are
provided along with their causes and solutions. You may encounter errors that are not mentioned here; if so, consult
the Hue website at gethue.com .
For instance, this error occurred in the beeswax_server.out log file:
Booting Derby version The Apache Software Foundation - Apache Derby - 10.4.2.0 - (689064): instance
a816c00e-0147-4341-f063-0000008eef18
on database directory /var/lib/hive/metastore/metastore_db in READ ONLY mode
Database Class Loader started - derby.database.classpath=''
14/07/17 00:38:21 ERROR Datastore.Schema: Failed initialising database.
Cannot get a connection, pool error Could not create a validated object, cause: A read-only user or
a user in a read-only database is not permitted to disable read-only mode on a connection.
The Hue user account needs to be able to access the Hive Metastore server directory /var/lib/hive/metastore/
metastore_db, but this error message indicates that it currently lacks the correct permissions. To rectify this, add a Hue
Linux user account (hue2) that you can use for Hue access to the Linux hadoop group.
If you see this error:
could not create home directory
it implies that there is a configuration error in the file core-site.xml. Check your proxy user settings that were set up
earlier in that file.
If you see an error like the secret key issue shown here:
Secret key should be configured as a random string
it means that the secret key has not been defined in the hue.ini file. See the secret key example configuration
previously used in the “Installing Hue” section.
When attempting to use the Sqoop functionality in Hue, you may see an error like this one:
shell.shelltypes Command '/usr/bin/sqoop2' for entry 'sqoop2' in Shell app configuration
cannot be found on the path.
It means that the Sqoop2 server that Hue depends on has not been installed. See the earlier section “Sqoop2
Server Setup for Hue.”
If a Linux-based account has an associated account in the Hue browser but does not have a home directory, any
of these errors may occur:
Failed to access filesystem root
hadoop.mapred_clusters.default Failed to contact JobTracker plugin at localhost:9290.
Failed to determine superuser of WebHdfs at
Failed to obtain user group information:
User: hue is not allowed to impersonate hue (error 401)
Just as your Linux hadoop account must have a home directory under /home/hadoop, and an associated .bashrc
file, so too must your Hue user account. The account that I use in these examples is Hue2; it has a home directory on
Linux (/home/hue2 ) and a home directory in HDFS (/user/hue2). It also has the same .bashrc contents as the Linux
hadoop user to set up its environment and a Linux user ID number greater than 500. If your account's user ID is not
greater than 500, you may encounter an error when trying to create scripts.
 
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