Using an External Database for Hue Using Cloudera Manager

Minimum Required Role: Full Administrator

The Hue server requires an SQL database to store small amounts of data, including user account information and the history of job submissions and Hive queries. The Hue server supports a lightweight embedded database and several types of external databases. See the procedures below to configure Hue with an external database. In the instructions that follow, dumping the database and editing the JSON objects is only necessary if you have data in SQLite that you need to migrate. Otherwise, you can skip those steps.

Continue reading:

Configuring the Hue Server to Store Data in MySQL
Configuring the Hue Server to Store Data in PostgreSQL
Configuring the Hue Server to Store Data in Oracle (Parcel Installation)
Configuring the Hue Server to Store Data in Oracle (Package Installation)

Configuring the Hue Server to Store Data in MySQL

In the Cloudera Manager Admin Console, go to the Hue service status page.
Select Actions > Stop. Confirm you want to stop the service by clicking Stop.
Select Actions > Dump Database. Confirm you want to dump the database by clicking Dump Database.
Note the host to which the dump was written under Step in the Dump Database Command window. You can also find it by selecting Commands > Recent Commands > Dump Database.
Open a terminal window for the host and go to the dump file in /tmp/hue_database_dump.json.

Remove all JSON objects with useradmin.userprofile in the model field, for example:

{
"pk": 14,
"model": "useradmin.userprofile",
"fields":
{ "creation_method": "EXTERNAL", "user": 14, "home_directory": "/user/tuser2" }
},

Set strict mode in /etc/my.cnf and restart MySQL:
```
[mysqld]
sql_mode=STRICT_ALL_TABLES
```

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)

In the Cloudera Manager Admin Console, click the Hue service.
Click the Configuration tab.
Select Scope > All.
Select Category > Database.
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
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);
```
Start the Hue service.

Configuring the Hue Server to Store Data in PostgreSQL

In the Cloudera Manager Admin Console, go to the Hue service status page.
Select Actions > Stop. Confirm you want to stop the service by clicking Stop.
Select Actions > Dump Database. Confirm you want to dump the database by clicking Dump Database.
Note the host to which the dump was written under Step in the Dump Database Command window. You can also find it by selecting Commands > Recent Commands > Dump Database.
Open a terminal window for the host and go to the dump file in /tmp/hue_database_dump.json.

Remove all JSON objects with useradmin.userprofile in the model field, for example:

{
"pk": 14,
"model": "useradmin.userprofile",
"fields":
{ "creation_method": "EXTERNAL", "user": 14, "home_directory": "/user/tuser2" }
},

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

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

Install the PostgreSQL server.

RHEL

$ sudo yum install postgresql-server

SLES

$ sudo zypper install postgresql-server

Ubuntu or Debian

$ sudo apt-get install postgresql

Initialize the data directories.
```
$ service postgresql initdb
```
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
```

Start the PostgreSQL server.

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

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
```

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

Restart the PostgreSQL server.
```
$ sudo service postgresql restart
```

Verify connectivity.

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

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

In the Cloudera Manager Admin Console, click the Hue service.
Click the Configuration tab.
Select Scope > All.
Select Category > Advanced.
Specify the settings for Hue Server Configuration Advanced Configuration Snippet:
Note: If you specify the database host, port, username, password, and name in the respective Service-Wide > Database > Hue Database * properties, you can omit those properties from the configuration. In particular, you can avoid storing the password in the Hue configuration file in plain text.
```
[desktop]
[[database]]
host=localhost
port=5432
engine=postgresql_psycopg2
user=hue
password=secretpassword
name=hue
```
Click Save Changes to commit the changes.

Optionally restore the Hue data to the new database:

Select Actions > Synchronize Database.

Determine the foreign key ID.

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

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

postgres=# ALTER TABLE auth_permission DROP CONSTRAINT content_type_id_refs_id_XXXXXX;

Delete the rows in the django_content_type table.

postgres=# TRUNCATE django_content_type CASCADE;

In Hue service instance page, Actions > Load Database. Confirm you want to load the database by clicking Load Database.

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;

Start the Hue service.

Configuring the Hue Server to Store Data in Oracle (Parcel Installation)

Use the following instructions to configure the Hue Server with an Oracle database if you are working on a parcel-based deployment. If you are using packages, see Configuring the Hue Server to Store Data in Oracle (Package Installation).

Install the required packages.

RHEL

$ sudo yum install gcc python-devel python-pip python-setuptools libaio

SLES:

Python devel packages are not included in SLES. Add the SLES Software Development Kit (SDK) as a repository and then install:

$ zypper install gcc libaio python-pip python-setuptools python-devel

Ubuntu or Debian

$ sudo apt-get install gcc python-dev python-pip python-setuptools libaio1

Download and add the Oracle Client parcel to the Cloudera Manager remote parcel repository URL list and download, distribute, and activate the parcel.
For CDH versions lower than 5.3, install the Python Oracle library:
Note: HUE_HOME is a reference to the location of your Hue installation. For package installs, this is usually /usr/lib/hue; for parcel installs, this is usually, /opt/cloudera/parcels/<parcel version>/lib/hue/.
```
$ HUE_HOME/build/env/bin/pip install cx_Oracle
```
For CDH versions lower than 5.3, upgrade django south:
```
$ HUE_HOME/build/env/bin/pip install south --upgrade
```
In the Cloudera Manager Admin Console, go to the Hue service status page.
Select Actions > Stop. Confirm you want to stop the service by clicking Stop.
Select Actions > Dump Database. Confirm you want to dump the database by clicking Dump Database.
Click the Configuration tab.
Select Scope > All.
Select Category > Advanced.
Set the Hue Service Advanced Configuration Snippet (Safety Valve) for hue_safety_valve.ini property.
Note: If you specify the database host, port, username, password, and name in the respective Service-Wide > Database > Hue Database * properties, you can omit those properties from the configuration. In particular, you can avoid storing the password in the Hue configuration file in plain text.
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}
```

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;

Go to the Hue Server instance in Cloudera Manager and select Actions > Synchronize Database.
Ensure you are connected to Oracle as the hue user, then run the following command to delete all data from Oracle tables:
```
> set pagesize 100;
> SELECT 'DELETE FROM ' || table_name || ';' FROM user_tables; 
```
Run the statements generated in the preceding step.
Commit your changes.
```
commit;
```
Load the data that you dumped. Go 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.
Start the Hue service.

Configuring the Hue Server to Store Data in Oracle (Package Installation)

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

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.
Unzip the Oracle client zip files.

Set environment variables to reference the libraries.

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

Create a symbolic link for the shared object:

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

Install the required packages.

RHEL

$ sudo yum install gcc python-devel python-pip python-setuptools libaio

SLES:

Python devel packages are not included in SLES. Add the SLES Software Development Kit (SDK) as a repository and then install:

$ zypper install gcc libaio python-pip python-setuptools python-devel

Ubuntu or Debian

$ sudo apt-get install gcc python-dev python-pip python-setuptools libaio1

For CDH versions lower than 5.3, install the Python Oracle library:
Note: HUE_HOME is a reference to the location of your Hue installation. For package installs, this is usually /usr/lib/hue; for parcel installs, this is usually, /opt/cloudera/parcels/<parcel version>/lib/hue/.
```
$ HUE_HOME/build/env/bin/pip install cx_Oracle
```
For CDH versions lower than 5.3, upgrade django south:
```
$ HUE_HOME/build/env/bin/pip install south --upgrade
```
In the Cloudera Manager Admin Console, go to the Hue service status page.
Select Actions > Stop. Confirm you want to stop the service by clicking Stop.
Select Actions > Dump Database. Confirm you want to dump the database by clicking Dump Database.
Click the Configuration tab.
Select Scope > All.
Select Category > Advanced.

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

Set the Hue Service Advanced Configuration Snippet (Safety Valve) for hue_safety_valve.ini property.
Note: If you specify the database host, port, username, password, and name in the respective Service-Wide > Database > Hue Database * properties, you can omit those properties from the configuration. In particular, you can avoid storing the password in the Hue configuration file in plain text.
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}
```

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;

Go to the Hue Server instance in Cloudera Manager and select Actions > Synchronize Database.
Ensure you are connected to Oracle as the hue user, then run the following command to delete all data from Oracle tables:
```
> set pagesize 100;
> SELECT 'DELETE FROM ' || table_name || ';' FROM user_tables; 
```
Run the statements generated in the preceding step.
Commit your changes.
```
commit;
```
Load the data that you dumped. Go 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.
Start the Hue service.

Using an External Database for Hue

Using an External Database for Hue Using the Command Line