The Inside View of VMs Layer
The Outside View of VMs layer provides an “outside” view of the different VM guests - the metrics reported at this layer are based on what the Acropolis server is seeing about the performance of the individual guest VMs. However, an outside view of the VM guest operating system and its applications may not be sufficient. For instance, suppose one of the disk partitions of the guest operating system has reached capacity. This information cannot be gleaned from host operating system. Likewise, bottlenecks such as a longer process run queue or a higher disk queue length are more visible using an internal monitor. Internal monitoring (from within the guest operating system) also provides details about the resource utilization of different application(s) or processes.
The tests mapped to the Inside View of VMs layer provide an “inside” view of the workings of each of the guests - these tests execute on an host, but send probes into each of the guest operating systems to analyze how well each guest utilizes the resources that are allocated to it, and how well it handles user sessions, TCP traffic, and network loading.
Figure 1 : The tests mapped to the Inside View of VMs layer