## 3 Provisioning Resource Pool View
### Quantitative Evaluation  
A comparative analysis of the method of applying BVMO, the system proposed in this study, and the method of creating a VM using only existing IaC tools was performed. OpenStack, a private cloud, was used for the experiment. In addition, to establish time measurement standards for each case, the log analysis process that occurred when creating a VM in OpenStack was performed. Figure 14 shows an excerpt of the parts that can be utilized among the logs generated when creating a VM in OpenStack. As shown in Figure 14, the OpenStack Nova component undergoes a two-step process to create an instance. The instance-creation process starts at the instance-create start time and provides the information received for VM creation to the hypervisor. Instance-spawning time measures the time taken to spawn an instance that Nova can control by  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Category** & **OS** & **Software** & **Data** & **Empty** \\ \hline \multirow{4}{*}{Resources} & Ubuntu20.04 & MySQL-CentOS & DB Class Video & \multirow{2}{*}{Default Vol 1} \\  & CentOS7 & MySQL-Ubuntu & Web Class Video & \multirow{2}{*}{Default Vol 2} \\  & Node.Js-Ubuntu & Web Class Data & & \\ \hline \multirow{4}{*}{Resources} & \multicolumn{4}{c}{Meaningful Cases} & \multirow{4}{*}{-} \\ \cline{1-1} \cline{3-5}  
receiving the VM created by the hypervisor. The Instance-build time refers to the time required to build a runnable VM during the verification process of the spawned instance. The VM created above performs an initialization to build an environment that users can utilize. Cloud-init is currently used as a cloud-instance-initialization tool. Figure 15 shows an excerpt from the cloud-init logs that can be utilized. In the case of cloud-init-execution logs, the data that can be utilized are the start and end times. The process of measuring the VM creation time based on the log-analysis results derived from Figures 14 and 15 is shown in Figure 16.  
Based on the time-measurement elements shown in Figure 16, the configuration of the experiment was divided into two cases when creating a VM: (1) when creating an empty instance with only the OS installed and (2) when performing software installation in the user-environment-initialization stage. In the case of the method using IaC listed in Table 8, the spawn time was 1.94 s on average, and the build time was 2.216 s on average. When using the BVMO presented in this study, the average spawn time was 3.154 s, and the average build time was 5.384 s. The  
Figure 16: VM-Creation Flow for Quantitative Evaluation. Figure 14: OpenStack Logs for Quantitative Evaluation. execution time, according to the specification interpretation, occurred in the process of the BVMO reusing existing resources. In addition, in the case of the initialization time, the method using IaC averaged 110.256 s, and the method using BVMO averaged 84.94 s, resulting in a reduction of approximately 25.316 s in the proposed BVMO. The initialization time of the OS, which is a major element of the computing system among existing resources, affects the initial creation speed of the VM. Therefore, it can be confirmed that the approach of pre-creating the combined OS resources proposed by the BVMO is effective. For the total execution time, the results include the spawn time, build time, initialization time and idle time according to the progress of the VM-creation flow. An average of 117.2 s for the IaC method and 95.6 s for the BVMO method were measured. It was confirmed that the proposed BVMO method could perform as fast as 21.8 s.  
Table 9 lists the experimental results for performing the software installation required by the user during the user-environment-initialization step. The software used in the experiment was performed by adopting npm, which can be installed from a Linux package repository.