preferredAvailabilityZones

A list of the Availability Zones in which cache nodes are created. The order of the zones in the list is not important.

This option is only supported on Memcached.

If you are creating your cluster in an Amazon VPC (recommended) you can only locate nodes in Availability Zones that are associated with the subnets in the selected subnet group.

The number of Availability Zones listed must equal the value of NumCacheNodes.

If you want all the nodes in the same Availability Zone, use PreferredAvailabilityZone instead, or repeat the Availability Zone multiple times in the list.

Default: System chosen Availability Zones.