Does an agent need to be installed on the server to be monitored?

It depends. The agent method requires installing an agent (CloudTest Conductor) on the server(s) that you want to monitor., while the agent-less approach makes use of open network protocols such as SSH (secure shell), SNMP, and RMI. The agent-less approach is the easiest and fastest option for monitoring but is unavailable on Windows and requires some ports to be opened in the firewall. The agent runs on major operating system platforms: Linux, Windows, and Mac OS X and requires only outbound ports.