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Amazon Web Services provides three price options for EC2 instances: On-Demand Instances, Spot Instances and Reserved...
Instances. RIs allow developers to optimize AWS compute capacity at a discounted price. Using Reserved Instances could result in savings of over 50%, according to AWS and cloud cost optimization tool vendors. However, the level of detail involved in choosing an RI plan, including selecting different instance types and commitment durations, makes the purchasing decision challenging.
As a cloud environment grows, so does the complexity of tracking instance use and RI opportunities within an AWS instance pool. Monitoring instances can help ensure you're using them properly. And there are five types of AWS Reserved Instances reports developers can use to optimize cloud costs.
The RI inventory report
This basic report lists information about all of AWS Reserved Instances in the environment It includes all features such as RI commitment types and durations, applied instances, expiration dates, and upfront and hourly fees. With this, you can move on to more detailed usage analysis reports.
On-Demand vs. Reserved Instances report
This is a primary report to help admins learn the distribution of your compute costs between On-Demand instances and RIs. This report gives a clear picture of On-Demand capacity growth for a consolidated view of On-Demand resource spending. Admins clearly see how they could save money by purchasing RIs.
This report should help you decide between buying either multiple RIs for workloads running in parallel or a single RI that can be used to consolidate multiple workloads running at different times. It is important to segment costs between your organization's business units and learn about possible cross-unit optimization opportunities, such as consolidating on-demand resources across an entire organization.
Unused Reserved Instances report
Buying reserved capacity and not using all of it can be financially devastating. Fortunately, unused reserved capacity can be allocated between units or applications. So it's important to know that you can apply RI credits between linked accounts that are under the same consolidated billing account. You can refer to the Unused Reserved Instances Report to find these opportunities, track your resource usage (including which application workloads are running) and average CPU and memory use. This report can also highlight redundant RI capacity as well as highly used On-Demand instance candidates to more easily re-apply RI credits.
Consolidated RI performance
In addition to operational RI lists and usage reports, corporate finance must be able to report costs and trends on both a monthly and annual basis. Summary reports show how much an organization spent on RIs and how much can be saved. These summaries enable managers to govern their AWS cloud expenses and take the lead if the IT team doesn't show consistent cost efficiencies.
The 'What if' report
The 'What if' is a bonus interactive report that goes beyond a simple column report; it's a good supplement to the On-Demand vs. RI report. IT pros enter what-if scenarios based on consistent on-demand compute capacity use. The outcome shows potential changes in the current forecasted trend. This simulation report can also be driven by summaries of other detailed RI reports that recommend purchasing and re-applying RI credits.
Other methods for monitoring instance cost
Cost is one of the major drivers of cloud adoption, but with the introduction of various purchasing models, it becomes difficult to manage these costs. IT teams must constantly compare On-Demand Instances and RIs. One of the main advantages of AWS Reserved Instances is that you can apply credits to appropriate compute use, including single or multiple instances.
In addition to AWS Trusted Advisor, multiple cloud cost optimization tools address the complexity involved in RI optimization. By providing these reports, vendors give customers a closer look at their workloads to help better align them, as well as demand, AWS cloud usage and costs.
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