You can add vCenter Servers to vMA using the standard/default fastpass authentication (fpauth). The vMA's fastpass authentication method provides a mechanism to cache the target server's credentials, on the vMA machine, so that you don't have to authenticate every time you run a command against the target server.
Note
Much like the adauth policy, every connection is authenticated but not every command to the authenticated target.
The domain user or its AD group should be assigned at least a read-only role at the target vCenter Server.