I am looking to create some load balancing servers with high availability.

Following this model: How To Set Up Highly Available HAProxy Servers with Keepalived and Floating IPs on Ubuntu 14.04

As I have no experience with this type of configuration, are the security certificates and Apache installed on the load balancing server or only on the servers containing the application?

I considered using DigitalOcean’s native load balancing service, but as I specifically need multiple security certificates and our own, I couldn’t use it.

Another hardware issue, do these balancing servers need to have more RAM or CPU?