Hello, I'm new to HAProxy and am trying to setup a TCP balancing of services using 'shared' least-connection balancing and was wondering if this was possible with HAProxy. We're partitioning our services across multiple servers and want to use a 'dual-redundant' type approach to distributing load. Each service will be located on at least three servers. This will allow us to manage server failure and maintain a higher peak rate than a more traditional mirrored redundancy arrangement.
Basically, my goal is as follows: 4 servers each house three services server 1 : service a, b, c server 2 : service b, c, d server 3 : service a, c, d server 4 : service a, b, d service a is on port 9020 service b is on port 9021 service c is on port 9022 service d is on port 9023 If server 1 goes down, I want the load to be evenly distributed between the other three servers across services. E.g. I want the least connections balancing counts to include all services, not just one particular service. For example, if we are maintaining the following connection counts: 300 for a, 600 for b, 900 for c and 300 for d, we would have the following up and down states (example distribution, others are possible): _Up State_ server 1 : a (100), b(150), c(275) = 525 server 2 : b(125), c(300), d(100) = 525 server 3 : a(100), c(325), d(100) = 525 server 4 : a(100), b(325), d (100) = 525 _Down State A_ (after stabilization period) server 1: down server 2: b(150), c(450), d(100) = 700 server 3: a(150), c(450), d(100) = 700 server 4: a(150), b(450), d(100) = 700 _Down State B_ (after stabilization period) server 1: down server 2: down server 3: a(75), c(900), d(75) = 1050 server 4: a(225), b(600), d(225) = 1050 There is some complexity here that isn't warranted at 4 servers but the redundancy model allows us to do a number of useful things. Also, while the example has each service existing the same number of times, in reality the number of copies of a service would vary depending on other factors (load, response curve, etc). Is this possible out of the box with just a configuration file? thanks for any guidance, Jacques
