The current upstream's heat resource, 'OS::Designate::Zone'[1] doesn't have attributes[2].

The attributes property should be assigned like below.
~~~
heat_template_version: 2015-04-30
...
resources:
...
the_resource:
type: OS::Designate::Zone
properties:
description: String
email: String
name: String
primaries: [Value, Value, ...]
ttl: Integer
type: String
attributes:

<-- HERE
~~~

[1] https://docs.openstack.org/heat/latest/template_guide/openstack.html#OS::Designate::Zone
[2] https://docs.openstack.org/api-ref/dns/dns-api-v2-index.html#create-zone

[Background]
There is a use case that the user wants to use Designate scheduler with multipool based on attributes.