The Hue Service

1. In the Cloudera Manager Admin Console, go to the Hue service status page.
2. Select Actions > Stop. Confirm you want to stop the service by clicking Stop.
3. In the Status Summary, click a Hue Server instance.
4. Select Actions > Dump Database. Confirm you want to dump the database by clicking Dump Database.
5. Open the database dump file (by default /tmp/hue_database_dump.json) and remove all JSON objects with useradmin.userprofile in the model field. (You can verify the location of the database dump file by searching for Database Dump File in the Hue configuration settings.)
6. Configure MySQL to set strict mode:

   [mysqld]
   sql_mode=STRICT_ALL_TABLES

7. Create a new database and grant privileges to a Hue user to manage this database. For example:

   mysql> create database hue CHARACTER SET utf8 COLLATE utf8_general_cs;
   Query OK, 1 row affected (0.01 sec)
   mysql> grant all on hue.* to 'hue'@'localhost' identified by 'secretpassword';
   Query OK, 0 rows affected (0.00 sec)

8. In the Cloudera Manager Admin Console, click the Hue service.
9. Click the Configuration tab.
10. Expand the Service-Wide > Database category.
11. Specify the settings for Hue Database Type, Hue Database Hostname, Hue Database Port, Hue Database Username, Hue Database Password, and Hue Database Name. For example, for a MySQL database on the local host, you might use the following values:
    • Hue Database Type = mysql
    • Hue Database Hostname = host
    • Hue Database Port = 3306
    • Hue Database Username = hue
    • Hue Database Password = secretpassword
    • Hue Database Name = hue
12. Optionally restore the Hue data to the new database:
    1. Select Actions > Synchronize Database.
    2. Determine the foreign key ID.

       $ mysql -uhue -psecretpassword
       mysql > SHOW CREATE TABLE auth_permission;

    3. (InnoDB only) Drop the foreign key that you retrieved in the previous step.

       mysql > ALTER TABLE auth_permission DROP FOREIGN KEY content_type_id_refs_id_XXXXXX;

    4. Delete the rows in the django_content_type table.

       mysql > DELETE FROM hue.django_content_type;

    5. In Hue service instance page, click Actions > Load Database. Confirm you want to load the database by clicking Load Database.
    6. (InnoDB only) Add back the foreign key.

       mysql > ALTER TABLE auth_permission ADD FOREIGN KEY (content_type_id) REFERENCES django_content_type (id);

13. Start the Hue service.

1. In the Cloudera Manager Admin Console, go to the Hue service status page.
2. Select Actions > Stop. Confirm you want to stop the service by clicking Stop.
3. In the Status Summary, click a Hue Server instance.
4. Select Actions > Dump Database. Confirm you want to dump the database by clicking Dump Database.
5. Open the database dump file (by default /tmp/hue_database_dump.json) and remove all JSON objects with useradmin.userprofile in the model field. (You can verify the location of the database dump file by searching for Database Dump File in the Hue configuration settings.)
6. Install required packages.

   RHEL

   $ sudo yum install postgresql-devel gcc python-devel

   SLES

   $ sudo zypper install postgresql-devel gcc python-devel

   Ubuntu or Debian

   $ sudo apt-get install postgresql-devel gcc python-devel

7. Install the Python module that provides the connector to PostgreSQL:
   • Parcel install

     $ sudo /opt/cloudera/parcels/CDH/lib/hue/build/env/bin/pip install setuptools
     $ sudo /opt/cloudera/parcels/CDH/lib/hue/build/env/bin/pip install psycopg2

   • Package install
     • CDH 4

       sudo -u hue /usr/share/hue/build/env/bin/pip install setuptools
       sudo -u hue /usr/share/hue/build/env/bin/pip install psycopg2

     • CDH 5

       sudo -u hue /usr/lib/hue/build/env/bin/pip install setuptools
       sudo -u hue /usr/lib/hue/build/env/bin/pip install psycopg2

8. Install the PostgreSQL server.

   RHEL

   $ sudo yum install postgresql-server

   SLES

   $ sudo zypper install postgresql-server

   Ubuntu or Debian

   $ sudo apt-get install postgresql

9. Initialize the data directories.

   $ service postgresql initdb

10. Configure client authentication.
    1. Edit /var/lib/pgsql/data/pg_hba.conf.
    2. Set the authentication methods for local to trust and for host to password and add the following line at the end.

       host
       hue
       hue
       0.0.0.0/0
       md5

11. Start the PostgreSQL server.

    $ su - postgres
    # /usr/bin/postgres -D /var/lib/pgsql/data > logfile 2>&1 &

12. Configure PostgreSQL to listen on all network interfaces.
    1. Edit /var/lib/pgsql/data/postgresql.conf and set list_addresses.

       listen_addresses = ‘0.0.0.0’     # Listen on all addresses

13. Create the hue database and grant privileges to a hue user to manage the database.

    # psql -U postgres
    postgres=# create database hue;
    postgres=# \c hue;
    You are now connected to database 'hue'.
    postgres=# create user hue with password 'secretpassword';
    postgres=# grant all privileges on database hue to hue;
    postgres=# \q

14. Restart the PostgreSQL server.

    $ sudo service postgresql restart

15. Verify connectivity.

    psql –h localhost –U hue –d hue 
    Password for user hue: secretpassword

16. Configure the PostgreSQL server to start at boot.

    RHEL

    $ sudo /sbin/chkconfig postgresql on
    $ sudo /sbin/chkconfig --list postgresql
    postgresql          0:off   1:off   2:on    3:on    4:on    5:on    6:off

    SLES

    $ sudo chkconfig --add postgresql

    Ubuntu or Debian

    $ sudo chkconfig postgresql on

17. In the Cloudera Manager Admin Console, click the Hue service.
18. Click the Configuration tab.
19. In the Category pane, click Advanced under Service-Wide.
20. Specify the settings for Hue Server Configuration Advanced Configuration Snippet:

    [desktop]
    [[database]]
    host=localhost
    port=5432
    engine=postgresql_psycopg2
    user=hue
    password=secretpassword
    name=hue

21. Click Save Changes.
22. Optionally restore the Hue data to the new database:
    1. Select Actions > Synchronize Database.
    2. Determine the foreign key ID.

       bash# su – postgres
       $ psql –h localhost –U hue –d hue
       postgres=# \d auth_permission;

    3. Drop the foreign key that you retrieved in the previous step.

       postgres=# ALTER TABLE auth_permission DROP CONSTRAINT content_type_id_refs_id_XXXXXX;

    4. Delete the rows in the django_content_type table.

       postgres=# TRUNCATE django_content_type CASCADE;

    5. In Hue service instance page, Actions > Load Database. Confirm you want to load the database by clicking Load Database.
    6. Add back the foreign key you dropped.

       bash# su – postgres
       $ psql –h localhost –U hue –d hue 
       postgres=# ALTER TABLE auth_permission ADD CONSTRAINT content_type_id_refs_id_XXXXXX FOREIGN KEY (content_type_id) REFERENCES django_content_type(id) DEFERRABLE INITIALLY DEFERRED;

23. Start the Hue service.

If you have a parcel-based environment, see Configuring the Hue Server to Store Data in Oracle (Parcel Installation).

1. Download the Oracle libraries at Instant Client for Linux x86-64 Version 11.1.0.7.0, Basic and SDK (with headers) zip files to the same directory.
2. Unzip the Oracle client zip files.
3. Set environment variables to reference the libraries.

   $ export ORACLE_HOME=oracle_download_directory 
   $ export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$ORACLE_HOME

4. Create a symbolic link for the shared object:

   $ cd $ORACLE_HOME 
   $ ln -sf libclntsh.so.11.1 libclntsh.so

5. Ensure Python 2.6 or newer is installed on the server Hue is running on.
6. For CDH versions lower than 5.3, install the Python Oracle library: $ HUE_HOME/build/env/bin/pip install cx_Oracle
7. Upgrade django south: $ HUE_HOME/build/env/bin/pip install south --upgrade
8. In the Cloudera Manager Admin Console, go to the Hue service status page.
9. Select Actions > Stop. Confirm you want to stop the service by clicking Stop.
10. In the Status Summary, click a Hue Server instance.
11. Select Actions > Dump Database. Confirm you want to dump the database by clicking Dump Database.
12. Click the Configuration tab.
13. Expand the Service-Wide > Advanced category.
14. Set the Hue Service Environment Advanced Configuration Snippet (Safety Valve) property to

    ORACLE_HOME=oracle_download_directory
    LD_LIBRARY_PATH=$LD_LIBRARY_PATH:oracle_download_directory

15. Set the Hue Service Advanced Configuration Snippet (Safety Valve) for hue_safety_valve.ini property. Add the following options (and modify accordingly for your setup):

    [desktop]
    [[database]]
    host=localhost
    port=1521
    engine=oracle
    user=hue
    password=secretpassword
    name=<SID of the Oracle database, for example, 'XE'>

    For CDH 5.1 and higher you can use an Oracle service name. To use the Oracle service name instead of the SID, use the following configuration instead:

    port=0
    engine=oracle
    user=hue
    password=secretpassword
    name=oracle.example.com:1521/orcl.example.com

    The directive port=0 allows Hue to use a service name. The name string is the connect string, including hostname, port, and service name.

    To add support for a multithreaded environment, set the threaded option to true under the [desktop]>[[database]] section.

    options={'threaded':true}

16. Grant required permissions to the Hue user in Oracle:

    grant alter any index to hue;
    grant alter any table to hue;
    grant alter database link to hue;
    grant create any index to hue;
    grant create any sequence to hue;
    grant create database link to hue;
    grant create session to hue;
    grant create table to hue;
    grant drop any sequence to hue;
    grant select any dictionary to hue;
    grant drop any table to hue;
    grant create procedure to hue;
    grant create trigger to hue;

17. Navigate to the Hue Server instance in Cloudera Manager and select Actions > Synchronize Database.
18. Generate statements to delete all data from Oracle tables:
    • If you are connected to Oracle as the Hue user, run the following command:

      SELECT 'DELETE FROM ' || table_name || ';' FROM user_tables; 

    • If you are connected to Oracle as a user that is not the Hue user, run the following command:

      SELECT 'DELETE FROM ' || '<schema_name>.' || table_name || ';' FROM user_tables;   

      Where <schema_name> is the correct hue schema, typically: hue.

19. Run the statements generated in the preceding step.
20. Load the data that you dumped. Navigate to the Hue Server instance and select Actions > Load Database. This step is not necessary if you have a fresh Hue install with no data or if you don’t want to save the Hue data.
21. Start the Hue service.