Virtual IP address for DNS - Qlik Sense

[chrishayes]

Hello Qlikies:

I have deployed a multi-node Qlik Sense  Enterprise September 2018 site. I have attached a diagram of my deployment. I have a Central and Rim node. The Rim node is set up for failover. This is an on-site deployment.

My Central node went down last night and the failover worked perfectly from the application's perspective. However, I have a DNS entry that users use to access Qlik. The URL (qlik.[company name].com) points to the Central node, and since it was down, users could not access Qlik. 

My infrastructure guy mentioned that they could create a virtual IP address that the vanity URL would point to and then Windows would send the user to whichever server was up and running. I also have load balancing turned on within the QMC between the two servers.

My question is would the solution above work with Qlik Sense? Could I leave load balancing turned on within the QMC or would I have to turn that off? I'm sure someone has gone through this scenario, so any advice would be appreciated. I would like to be able to solve this without having to acquire any network hardware appliance.

Thanks!

[Bastien_Laugiero]

Hello,

I believe the load balancing in the QMC you are referring to is the one available in the Virtual Proxy configuration.

If that's the case, then this function only load balance the engine service.

What you are looking for is to load balance the proxy service so that users can continue accessing the web interface (QMC / Hub) if one of the nodes goes down.

There is no native function in Qlik Sense to load balance the proxy service but this is doable by using third-party technology. 

There are several requirements to ensure the load balancing will work properly. Probably the most important one is called "Sticky Session". This means that if a user starts a session on Server A, then the entire session needs to be redirected to Server A. So having a Virtual IP to redirect the traffic to Server A or Server B will work but only by ensuring that the requirements are met.

Here is an article listing the requirements for load balancing to work properly. Network Load Balancer (NLB) with Qlik Sense Enterprise April 2018 and later

Hope this helps!