VDi (Virtual Desktop Infrastructure) is one of the earliest applications that was used in hyper-convergent  systems. The closer the storage to the cpu and memory the better the performance.

Citrix director plugin, need to be connected to the nutanix cluster. if the connection fails with a message "Unable to connect to the host”, you can easily address it by:

1- Allow ICMP traffic and make sure port 9440 is also allowed between Citrix Director and Nutanix cluster.

2- Make sure there is no proxy server configured in the browser configuration

The above is reported in the Nutanix public KB article:

https://portal.nutanix.com/#/page/kbs/details?targetId=kA00e000000LKiBCAW