Proposal that for all of our services, we define the following variables:

<servicename>_port:
<servicename>_listen_addresses:
<servicename>_server_address:

A service binds to addresses in <servicename>_listen_addresses on <servicename>_port. Clients of the service connect to <servicename>_server_address (on <servicename>_port). So instead of e.g., the senu module having sensu_redis_server, the sensu module would depend on the redis module and would use redis_server_address.

This will in general require separating role defaults from the actual implementation (so, having both a redis role that sets the defaults, and a redis/server role that performs the actual configuration)