SFR5 - Availability Zones
Modules that deploy zone-redundant resources MUST enable the spanning across as many zones as possible by default, typically all 3.
Modules that deploy zonal resources MUST provide the ability to specify a zone for the resources to be deployed/pinned to. However, they MUST NOT default to a particular zone by default, e.g. 1
in an effort to make the consumer aware of the zone they are selecting to suit their architecture requirements.
For both scenarios the modules MUST expose these configuration options via configurable parameters/variables.
For information on the differences between zonal and zone-redundant services, see Availability zone service and regional support