You must install a Management Agent on each Windows machine hosting IaaS components.
About this task
For enterprise installations, a Management Agent is not required for the MS SQL host.
If your primary vRealize Automation appliance fails, you must reinstall Management Agents.
Management Agents are not automatically deleted when you uninstall an IaaS component. Uninstall the Management Agent as you would uninstall any Windows program with the Add or Remove program tool.