What is PowerDNS software? Is it necessary for SolusVM?
PowerDNS is a 3rd-party software that allows managing own name server if this functionality is required in your infrastructure - https://www.powerdns.com/
SolusVM allows to integrate PowerDNS and manage domain zones using SolusVM web interface - https://docs.solusvm.com/display/BET/PowerDNS+Installation
It is not a vital feature for SolusVM functionality and can be installed on demand.