The role of Cloudhealth

Offering a service to get calculated discounts by reserving instances, Amazon's goal is clear: to better capacity planning by identifying the cloud infrastructure used by the user segment, while also giving users direct benefits. So far, the industry has a certain understanding of the reservation, including the type (Heavy, Medium, Light) and the terms (1 or 3 years), but here's 6 reservation examples related matters you may not understand.

1. Double Benefits

Reserving instances brings a double benefit to the user: first, the ability to compute the discount; second, the capacity of the reservation. Now, many Amazon users have come to realize the cost reduction of price discounts, but the second benefit is often overlooked: the guarantee from Amazon that you can publish instances of this type (instance type, available region, operating system) at any time during the contract period. Amazon is the only cloud vendor to provide this assurance, so this feature is definitely a big competitive advantage.

In many ways, AWS is also a victim of this: its ability to expand can, as always, support the rapid growth of user demand, and rarely allow users to be limited by capacity, so users tend to ignore this is commendable.

2. Options for reserving instances

By randomly evaluating the use of available reservations and running instances, the choice of reserved instances is often based on an hourly assessment. Evaluate all usages of the instance within this hour and determine whether there is a reservation instance that is appropriate for this usage-or not, by matching instance types (such as M2.2xlarge), available areas (such as US-EAST-1A), and operating systems (such as Linux). Because there are many different types of reservations and services that can be matched, the choice of reserved instances tends to be the least used. It is also noteworthy that there is a close relationship between the reservation instance and the purchase account, which will be discussed in more detail below.

Admittedly, this random approach to reserving an instance is a very powerful feature, but it should not be overlooked that this approach is also a source of distress for users. Every once in a while, I offer advice to those who buy reserved instances for a variety of purposes, such as marketing, to find ways to get the cost-benefit from the reservation instance.

3. Cross-account fluctuations

One of the features of reserving instances is that they can float across accounts. This feature is available only when multiple accounts allow the consolidation of bills, floating limited to the billing account and its corresponding connection account. This means that if you purchase a reservation instance in an account, but within an hour the account does not use the reservation instance, the reservation instance can offset the use of instances of other accounts in the consolidated bill. As mentioned above, the reservation instance is closely related to the purchase account. Therefore, this float occurs only if the account is not used in any instance and cuts down a certain cost.

It should be noted that while this reservation instance can be cost-effective, the capacity reservation does not have this feature. So, while you have an instance of reservation available in a account, Amazon does not guarantee that you can issue an equivalent instance in the B account, even if the accounts are connected to a comprehensive billing account.

4. VPC Reservation Instance

When a user purchases a reservation instance, the user must choose to purchase a reservation instance that is VPC or classic (NON-VPC) type. The explanation for this choice is not clear in Amazon's documentation. One of the questions I often hear is: if you choose the VPC type, can this type be applied to the classic instance? Explaining the ambiguity of the document creates a lot of confusion for the user's expected behavior (such as Rightscale Planforcloud's article--amazon VPC Reserved Instances vs EC2 Reserved), Here we try to explain.

Specifying Classic or VPC and the cost reductions associated with obtaining a reservation instance are not linked. If you buy a VPC reservation instance and have no equivalent instances running within an hour, the cost benefit of this VPC reservation instance can be passed on to the equivalent Classic (NON-VPC) instance being used. However, the capacity reservation advantage is provided only to instances of the specified type (Classic (NON-VPC)), so there is no guarantee that an equivalent transfer can be made.

5. Available Regional issues

The available areas are specified when the account is established, and if you have multiple accounts, it is likely that these accounts will use a different range of available. For example, if you have 3 accounts, a, B, and c,us-east available areas, these situations may occur:

If you run only one account, or if you have only one separate account, this problem will not affect you. However, if multiple accounts are connected to an integrated billing account, this may affect the account floating function described above. Therefore, in the above example, if you are us-east-1a in the designated available area of account A, and the free area of the C account does not include us-east-1a, then the float will not be possible.

6. Constrained by Data center

The data center will set up firewalls, so as AWS grows, physical data centers can become constrained. Amazon says that the available areas are only logical identifiers, which are mapped to multiple physical data centers when each account is established. If a datacenter does not support additional growth (also known as a constraint), all accounts mapped to this identifier will no longer be expanded, and the likelihood of such a constraint is proportional to the time that you built the Amazon account. As a result, the more new The account is, the less likely it is to happen, and the older the account, the greater the likelihood that the constraint will occur.

Fortunately, although you may not be able to publish new instances in the physical datacenter where the constraints are generated, you can still buy the reservation instances in the datacenter. Of course, you cannot do this by using the standard Self service mechanism provided by the AWS Console or API, and you must do so through account representations or failure submissions. It is important to note that in a constrained physical datacenter, instead of an on-demand instance, you can only use a reserved instance to elevate the capacity (therefore, this reservation instance must be directly applicable to the on-demand instance of the current operation).

It's a bit extreme, but in this case the best way is to migrate all instances from constrained data centers to an unconstrained datacenter.

The role of Cloudhealth

In the reservation instance, Amazon provides users with a very powerful feature that can help manage user infrastructure usage and cost-effectiveness. However, there are some subtle complexities in the decision making of buying, selling and fixing. Many of the features of Cloudhealth may help you solve these problems:

InterActive Alerts (interactive alert)---------proactive notification based on user-defined hours or cost-saving thresholds, where the reservation instance is not fully exploited.

Tiyatien Check (Health check)--As a routine health check for reserving instance usage, it will provide a reservation utilization pulse. It provides an intuitive visual angle for the reservation instance not to make full use of the recognition, cost saving suggestion and reserving instance expiration.

InterActive Reports (Interactive report)--For better analysis of the use of reservations and on-demand instances, this feature provides a variety of highly available custom reports that are delivered to key stakeholders on a regular basis.

Optimizers (Optimizer)--even in the case of an enterprise-scale purchase, it can make it easy to purchase, sell, and modify the reservation instance. When you purchase any budget reservation, it will provide you with the most cost-effective option, while at the same time it can give you a custom price analysis, including tiered discounts and enterprise agreements.

Multi-account Support (Multi-account support)-This feature allows all of the above functions to be single accounts, multiple accounts connected to a consolidated billing account, or even multiple integrated billing accounts.

Original link: http://www.cloudhealthtech.com/blog/6-Things-You-May-Not-Know-About-RIs

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                                                                                                                 (Translator/Shirongyang Zebian/yuping)