Office Online Server: Load balancing using KEMP LoadMaster

As part of my plans to build up a Skype for Business lab I was looking to deploy an Office Web App server and then found that Microsoft are renaming it to Office Online Server and its currently in preview. Rather than me deploying the tried and tested Office Web App Server in my lab I thought I’d push the boat out and deploy a preview version of Office Online Server and then link this to my Skype for Business deployment. Part one of this task is to deploy Offline Online Server which is very nicely documented on TechNet here so I wont bore you and go over it again.

Now that I’ve deployed my Office Online Server (I’m going to refer to it as OOS from now on) I wanted to load balance it using my existing deployment of a KEMP LoadMaster, I know I’ve only got one OOS server currently but its good practise to load balance it now in case I add a second one in the future.

Export & Import the SSL certificate

Whether you use a third party or internal PKI to issue your certificate used on your OOS server you’ll need to export it from your OOS server as a PFX file and then import it to your KEMP LoadMaster for use on the virtual service we are going to create below.

  1. Once you have your PFX file log into your KEMP LoadMaster and navigate to Certificates and click on SSL certificates and
  2. Then click on the Import Certificate button near the top to begin the import wizard
  3. Browse to the location of the PFX file
  4. Type in your passphrase used when exporting the certificate
  5. Give it a friendly name and click on Save.

Office Online Server

You should now have a newly imported certificate ready for use.

Adding a new virtual service for Office Online Server

After logging into your KEMP Loadmaster under Virtual Services click on Add New to begin. I’m using the templates from KEMP which means there is less setup work to do

  1. Select the template called Lync Office Web App Servers 2013.
  2. Change the Service Name to something like OOS (optional)
  3. Type in a virtual IP address to be used
  4. When done click on Add this Virtual Service

Office Online Server

Configuring the Virtual Service

Once the service has been added it will take you to the configuration page for the service, under standard options is SSL Properties.

  1. Highlight the certificate you previously imported and click the > button to assign it
  2. Click on Set Certificates to save the change

Offlce Online Server

Next go to the Real Servers section of the virtual service configuration

  1. Click on Add New
  2. Specify the IP address of your OOS server
  3. Click on Add This Real Server to confirm
  4. Then click on Back a couple of times and check the new virtual service is there and has an UP status


Now that you’re done test you can access your OOS server by visiting the URL¬† https://OOSServerFQDN/hosting/discovery and you should get returned a bunch XML without any certificate errors.

Adding the OOS Server to my Skype for Business lab

For this I need to go back into the Topology Builder:

  1. Expand the name of your site and then go into Shared Components / Office Web Apps Servers
  2. Right click and click New Office Web Apps Server
  3. Type in the FQDN of your OOS server deployment (the name on the certificate if your actual OOS server name is something different)

Topology Builder

Last but not least you must always publish your topology when you make changes like this:

Publish Topology

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