We use ansible without any GUI. On the managed nodes just ssh access is needed, no agent.
This let us manage 16 haproxy 2-node-clusters (32 nodes in total) running on two diferent linux flavors; some of the clusters have a similar configuration, some others are completely different. In our experience any configuration change (not only for haproxy, but also for other) can be deployed in a few seconds on one, few, many or all nodes, even over slow satellite links.
All configurations are versioned with Git. .marcoc
