# Digital Cloud Environment: Present Challenges and Future Forecast
## 4 Public Cloud Computing Resources  
This section describes the analysis of the specific GCC resources provided by Amazon Web Services (AWS) as an example, but the same approach can be applied to any other cloud provider, such as Microsoft Azure, IBM Cloud Services, Red Hat CloudForms, VMware Cloud Foundation, and other worldwide known leaders [21].  
AWS is one of the leading public cloud vendors in the IT world, having a wide variety of VMs to implement all the main IT techniques as a service like SaaS, PaaS, IaaS, LBaaS, DBaaS, etc. VMs are available in AWS as a selection of various VM instance types and sizes, allowing flexible scaling of CPU, memory, storage, and network to the required workload of the applications (Table 3). Migration from one instance size to another is possible at any moment and is very easy--just select a proper type and restart the VM. If a misbalance of computing resources is needed, there are special VM types accelerated and optimized for computing, memory, or storage.  
AWS pricing policy depends on the cloud region, the operating system (OS) installed, and the status of a VM--reserved, running, stopped, or terminated. Table 4 shows a pricing example for AWS instances of the M4 type listed in Table 3, (Supplementary Materials contain the Table 4's statistical raw data and calculations).  
Tables 3 and 4 show that in case of migration from any AWS instance to the nearest one, the computing resources of both CPU and memory are doubled and the price doubles as well.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**VM Instance** & **Virtual CPUs** & **Memory, GB** & \begin{tabular}{c} **Storage** \\ **Performance** \\ \end{tabular} & \
\begin{tabular}{c} **Storage** \\ **Volume, GB** \\ \end{tabular} &
\begin{tabular}{c} **Price per Hour** \\ **for OS Linux** \\ \end{tabular} \\ \hline m4.large & 2 & 8 & Optimized & 1 x 4 SSD & \$0.1 \\ m4.xlarge & 4 & 16 & Optimized & 1 x 8 SSD & \$0.2 \\ m4.2 xlarge & 8 & 32 & Optimized & 1 x 16 SSD & \$0.4 \\ m4.4 xlarge & 16 & 64 & Optimized & 1 x 32 SSD & \$0.8 \\ m4.10 xlarge & 40 & 160 & Optimized & 2 x 40 SSD & \$2.0 \\ m4.16 xlarge & 64 & 256 & Optimized & 2 x 80 SSD & \$3.2 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Prices for AWS instances of the M4 type running operating system (OS) Linux/Unix in the US East region [22].  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Risk** & **Risk Management** \\ \hline External fraud & Review the company’s security policy and protect the data \\ \hline Access issues & Monitor health check to ensure the cloud service is stable \\ \hline Internal fraud & Ask external cloud provider to track and log the user’s activities \\ \hline Vendor failure & Need alternative cloud vendor in case of a primary outage \\ \hline Cloud outage & Need backup network channel in case of a primary failure \\ \hline \hline \end{tabular}
\end{table}
Table 2: The risks associated with the public cloud.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**VM Instance** & \begin{tabular}{c} **Virtual** \\ **CPUs** \\ \end{tabular} & \begin{tabular}{c} **Memory,** \\ **GB** \\ \end{tabular} & \begin{tabular}{c} **Storage** \\ **Performance** \\ \end{tabular} & \
\begin{tabular}{c} **VM Bandwidth,** \\ **Mbps** \\ \end{tabular} &
\begin{tabular}{c} **Network** \\ **Performance** \\ \end{tabular} \\ \hline m4.large & 2 & 8 & Optimized & 450 & Moderate \\ m4.xlarge & 4 & 16 & Optimized & 750 & High \\ m4.2 xlarge & 8 & 32 & Optimized & 1000 & High \\ m4.4 xlarge & 16 & 64 & Optimized & 2000 & High \\ m4.10 xlarge & 40 & 160 & Optimized & 4000 & 10 Gigabit \\ m4.16 xlarge & 64 & 256 & Optimized & 10,000 & 25 Gigabit \\ \hline \hline \end{tabular}
\end{table}
Table 3: Amazon Web Services (AWS) instances of the M4 type with optimized storage [21].