The virtual appliances are pre-configured virtual machines that you add to your vCenter Server or ESXi inventory.
For operating system and high-level environment requirements, including information about supported browsers and operating systems, see the vRealize Automation Support Matrix.
An Active Directory is considered small when there are up to 25,000 users in the OU to be synced in the ID Store configuration. An Active Directory is considered large when there are more than 25,000 users in the OU.
The hardware requirements for vRealize Code Stream for Small Active Directories is:
18 GB memory
60 GB disk storage