How is this different from bamboo - also an HAproxy based LB thats via the marathon framework?
There are several differences: 1. We're coupled with the kernel and operating at layer 4. Specifically, we play with the conntrack subsystem. This means, you may pay a little higher cost for the first packet of a connection (because we've got to program the flow), but once the flow is programmed, it's totally going through kernel space. The way Minuteman is meant to be used is to act as the underlying router of a connection pool, or some such.
2. We expose the pools as "VIPs" or Virtual IPs. When you expose a service, you specify an IP-port pair (like 1.2.3.4:5000). In my opinion, that's a little bit nicer than Bamboo's routing.
3. We work with all Mesos frameworks.
4. We have an underlying distributed control plane (https://github.com/dcos/lashup), which lets us detect failures incredibly fast. We've evaluated its capabilities here: https://github.com/dcos/minuteman#evaluation
So it seem the kernel is doing most of the work to handle the connection. The load balancer isn't really proxying the connections.