Which local host utility is specifically designed for primary, real-time performance monitoring in vSphere?

The utility specifically designed for primary, real-time performance monitoring in vSphere is esxtop. This tool provides a rich interface that allows administrators to monitor the performance of the hypervisor and its virtual machines in real-time. With esxtop, users can view various metrics related to CPU, memory, network, and storage performance, helping them to troubleshoot issues and optimize resource usage within their environment.

While other options like top and the vSphere Command-Line Interface (CLI) do provide some level of monitoring, they serve different purposes. "top" is a standard Linux utility for monitoring processes, which does not provide VMware-specific metrics. The vSphere CLI is a command-line interface that allows for various management tasks but is not focused solely on real-time performance monitoring. Meanwhile, resxtop is used in vRealize Operations instead of being a primary tool in the vSphere environment. Thus, esxtop stands out as the appropriate choice for real-time performance insights directly related to vSphere operations.