CARP IP level load balancing

[Tom Judge]

Luiz Otavio O Souza wrote:
>>> Date: Tuesday, January 20, 2009, 9:30 AM
>>> In FreeBSD there is only ARP level LB, that is in some cases
>>> just not enough for load balancing.
>>> Is there any plans to port IP level LB from OpenBSD, and,
>>> if yes, will it be ported to 7x and 6x?
>>>
>>> In my opinion, full CARP realization is one step towards
>>> LVS-equal functionality.
>>
>> Curious as to your specific needs. Is LAGG load balancing of no use 
>> at IP level?
>>
>> Barney
>>
>
> hmm... with lagg you have two (or more) phisical connections sharing 
> the same ip, with carp you will have two (or more) servers sharing the 
> same ip.
>
> i think lagg will not help.
>
> i would like to give a try on carp ip balance, but i dont have the 
> time for now. i also like to known if someone else is working on this.
>
> Luiz
>
The way that we deploy IP level load balancing,  we have 2 PF firewall 
routers on the network edge that handle the IP load balancing using 
round robin route to.   (We are using direct sender reply) Then we have 
2+ nodes with a carp address for each node, with backups on the other 
nodes.  These carp addresses are the addresses used in the route to 
rule.  The public IP's are assigned to the loop back interfaces of the 
application nodes and the default gateway of the application nodes is 
back out the PF firewalls.

Here is a diagram to help explain:  http://www.tomjudge.com/tmp/Diagram1.png

AFAIK there is no Layer 3 load balancing support built in to carp in 
FreeBSD, however this solution will work if you have firewalls that can 
help you out with the distribution.

Tom