By default, ACI-wide flooding is disabled. Because flooding is disabled, connecting to a DHCP server is only possible if it is in the same EPG as the client (as flooding within a bridge domain is enabled).
The options, therefore, are to have one DHCP server per-EPG, which would be wasteful on "compute" resources and on administrative time, or to use a DHCP relay and have one, central, server.
In this recipe, we will be setting up a DHCP relay.