You can get the cluster devices with all devices inside these cluster by using a Device42 Object Query Language (DOQL).

The query is:

select
 m.name as Cluster_Device,
 string_agg(d.name, '; ') as "Devices in Cluster"
from view_device_v1 m join view_devices_in_cluster_v1 c on c.parent_device_fk = m.device_pk 
join view_device_v1 d on d.device_pk = c.child_device_fk

where
 m.type like '%cluster%'

group by
 m.name

To run the query please use the following URL:

https://D42_IP/admin/rackraj/tools/d42viewer/doql/

Replacing the D42_IP with your appliance IP or DNS

And use "," as column separator

The output will be a CSV file which will be downloaded on your computer.