Do I need 3 LB to do this or I can do it with only one ? The screenshot of Barracuda LB seem to show many "virtual LB", so I guest it's a yes ?
2) So... it's service only ?
On the Barracuda and some page, they are talking about "service" and not "server" LB. Can I LB a whole serveur ? Like all service from an IP xxx.xxx.xxx.234 to a server ? Or I can only do "HTTP -> SRV1" "DNS -> SRV1" ? If no, what happen to service that the LB didn't know (like cPanel) ?
3) An Internal Network ? what About cPanel ?
According to my search, LB are working like this :
EXTERNAL IP of SERVICE (xxx.xxx.xxx.200) -> INTERNAL IP SERVER 1(10.0.0.25), INTERNAL IP SERVER 2 (10.0.0.26)
So, I need to configure the server with an Internal IP cause else, it will conflit on the "local network". The probleme is, cPanel will be using the "Internal IP" to make all of his configuration... so if a user add a new website, he will configure it with 10.0.0.25, this won't since the external IP will be xxx.xxx.xxx.200 and Apache won't anwser to this virtual host. What can I do ?
Can I do this ? (same internal IP as the external ?)
EXTERNAL IP (22.214.171.124) -> SERVER 1 INTERNAL IP (126.96.36.199), SERVER 2 INTERNAL IP (10.0.0.26)
If yes, I will configure the second serveur without cPanel and only sync the configuration and files. So in case of "crash" of the server 1, cPanel won't be working, but website won't be down...
Got a better idea ?
Thanks, hope I'm clear you will be able to help me and sorry for my english If you have questions, just ask !
Any load balancer worth its salt can handle several services at once. So, it could load balance HTTP traffic to one IP address, and send all traffic to another IP address to a single box. In fact, it's even smart enough that it can read the Host: header and treat traffic to different vhosts differently.
DB traffic is harder to Load balance, as you have to synchronize the database on the back end, which is nontrivial. Make sure you understand exactly what is going on here, and a load balancer may play some part of your database network design.
(2) You probably can send all incoming requests to an IP address to a single machine, but I haven't used the barracuda boxes so I can't verify it.
(3) Maybe scratch cPanel altogether and go with a different system for your load balanced customers?