Jedox Load Balancing – The Master and the Slave

I had the pleasure the other week of visiting and working closely with the Jedox Team at Dawin Consulting in Seoul, Korea. They are a fantastic group of professionals working hard on their first major Jedox project for a very large Korean company. It is a big project and a team of four consultants are on it full time. 

Their client had the requirement of setting up Load Balancing as well as full Failover for their Jedox Servers. Load Balancing allows the incoming traffic to the Jedox Server to be spread over multiple web servers, which is helpful only when you have a big volume of web users.

The Load Balancing requirement architecture was as follows:

Load_Balancing_Inverted

As per the diagram above, the requirement was that users will be accessing the Jedox system via multiple Web Servers, but actually connecting to the same OLAP Server.

Setting up Jedox to Handle Load Balancing
To do this, you require 2 or more servers in which Jedox you can install Jedox. The Server that will have the active MOLAP server will be referred to as the “Master”. The additional servers that will just have the Web Service running will be called the “Slaves”. In this example, we will assume that we have 2 servers only – a Master and 1 Slave. Also, ensure that either all relevant ports are accessible through the firewalls of each server or just turn the firewall off completely for the purpose of this exercise.

Install Jedox on both Master and Slave Server. Ensure you do a full install on each server. However, as you will probably only have one licence key, install this on the Master server. You will not need a licence key for the Slave server, as the slave servers will not be running the MOLAP server.

Once you have done a full install, you need to tweak some settings on both servers. As the Slave server will only be using its HTTPD Service (ie the web service), you can stop all the other services (ie Core, MOLAP, MDX Interpreter, etc).

NOTE: Before changing any of these files on any servers, ensure you have a backup up all of the original files so you have a roll-back position in case of something going wrong.

Settings to Change on the Slave Server(s)

STEP 1:
in file C:\Program Files\Jedox\Jedox Suite\httpd\conf\httpd.conf , confirm this setting:
ServerName 127.0.0.1:80 (or other port number set during installation)
Should be
ServerName 0.0.0.0:80
STEP 2:
in file C:\Program Files\Jedox\Jedox Suite\httpd\conf\httpd.conf, we will be replacing the 127.0.0.1 to the address of the Master server. Change the following block of code: 


#ProxyPass /ub/ ajp://127.0.0.1:8194/ min=2
ProxyPass /ub/ ajp://127.0.0.1:8194/ retry=0
ProxyPassReverse /ub/ ajp://127.0.0.1:8194/
ProxyPassReverseCookiePath / /ub/

### ETL
Alias /tc/web-etl ../tomcat/webapps/web-etl
ProxyPassMatch /tc/web-etl/app/service/(.*)$ ajp://127.0.0.1:8010/web-etl/app/service/$1
ProxyPass /tc/web-etl !
ProxyPass /tc ajp://127.0.0.1:8010/
ProxyPassReverse /tc ajp://127.0.0.1:8010/
ProxyPassReverseCookiePath / /tc/

### Palo Pivot
ProxyPass /web-palo-ng ajp://127.0.0.1:8010/web-palo-ng
ProxyPassReverse /web-palo-ng ajp://127.0.0.1:8010/web-palo-ng

to


#ProxyPass /ub/ ajp://<address of master molap server>/ min=2
ProxyPass /ub/ ajp://<address of master molap server>:8194/ retry=0
ProxyPassReverse /ub/ ajp://<address of master molap server>:8194/
ProxyPassReverseCookiePath / /ub/

### ETL
Alias /tc/web-etl ../tomcat/webapps/web-etl
ProxyPassMatch /tc/web-etl/app/service/(.*)$ ajp://<address of master molap server>:8010/web-etl/app/service/$1
ProxyPass /tc/web-etl !
ProxyPass /tc ajp://<address of master molap server>:8010/
ProxyPassReverse /tc ajp://<address of master molap server>:8010/
ProxyPassReverseCookiePath / /tc/

### Palo Pivot
ProxyPass /web-palo-ng ajp://<address of master molap server>:8010/web-palo-ng
ProxyPassReverse /web-palo-ng ajp://<address of master molap server>:8010/web-palo-ng

STEP 3:
Open C:\Program Files\Jedox\Jedox Suite\httpd\app\etc\config.php. Change


define('CFG_PALO_HOST', '127.0.0.1');

to


define('CFG_PALO_HOST', <ip of master molap server>);

Settings to Change on the Master Server
OK. So at this point all of your slave servers are now pointing to the Master server for their various components. Now we need to make some changes on the Master server to allow incoming connections from the Slave Servers.

STEP 1:
Open …\core2\ui_backend_config.xml Change


 <tcp address="127.0.0.1" port="8194" />

to


 <tcp address="0.0.0.0" port="8194" />

This allows connections to the core server from outside the master server.

STEP 2:
Go to C:\Program Files\Jedox\Jedox Suite\tomcat\conf\server.xml. To Allow connections to the ETL from outside the master server, change the line


 <Connector port="7775" address="127.0.0.1" connectionTimeout="20000" protocol="HTTP/1.1" redirectPort="7743" />

to


 <Connector port="7775" address="0.0.0.0" connectionTimeout="20000" protocol="HTTP/1.1" redirectPort="7743" />

In the same file, change this line for AJP (for Report Manager, File Manger)


<Connector port="8010" protocol="AJP/1.3" address="127.0.0.1" redirectPort="7743" />

to


<Connector port="8010" protocol="AJP/1.3" address="0.0.0.0" redirectPort="7743" />

Connection Manager
Once this is all in place, you will need to change the Jedox Connections in Connection Manager. Assuming you have the same connection names as per the default install, change the localhost and localhost_static to the Master IP address. You can also use the IP address for the Load Balancer here, which is useful, particularly if you are also implementing a Fail Over regime on top of the Load Balancing. Once all your changes are in place, restart all services on the Master Server, and restart the JedoxSuiteHttpdService on the Slave server(s).

Now go to the IP address of the Slave server in a browser. You will now be using the web service of the Slave server but connecting to the MOLAP server of the Master. Type in the IP of the Master, and you should now be connecting to the Master web server.
Follow the above again for each slave server that you have.

The Load Balancing bit..
Once we completed the configuration, we handed the IP addresses over to the clients IT Department for configuration inside the Load Balancer. There are many load balancing software products out there, but in this case the Windows Server 2012 Network Load Balancing (NLB) was used. The NLB has an IP address of its own, and the IP addresses of the Master and Slave are routed to this address, so the server access is seamless as far as the users are concerned.

Please note that the above changes to the Jedox filesystem comes without warranty and does not guarantee that future changes to the binaries could potentially impact this approach to load balancing.

One thought on “Jedox Load Balancing – The Master and the Slave

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