Enabling and Purchasing a Reserved Instance

Quota Constraints

• The quota for the number of RIs that you can purchase in the current region is displayed in the upper left area of the Reserved Instance page. The quota for the number of RIs that can be purchased by a user in each region is 20.
• The quota for the number of RIs is automatically reset every month.
• The remaining quota for the number of RIs (Remaining quota = Total quota – Used quota) is reduced only after more RIs are purchased. It will not be changed if RIs are modified, split, combined, or unsubscribed.

Enabling RIs

Before purchasing an RI, contact customer service to apply for the required permissions.

Purchasing an RI

1. Log in to the management console.
2. Click in the upper left corner and select your region and project.
3. Click . Under Compute, click Elastic Cloud Server.
4. In the navigation pane on the left, choose Reserved Instance.
5. Click Buy RI.

   The Buy RI page is displayed.

6. Confirm the region.

   If the RIs in the selected region do not meet your requirements, select another region.

7. (Optional) Select Show offerings that reserve capacity to view the AZs that support capacity reservations.
   • Zonal RIs offer capacity reservation.
   • Regional RIs offer capacity reservation.
8. (Optional) Select an AZ to purchase a zonal RI for capacity reservation.

   Perform this operation only when you purchase RIs for a specified AZ.

9. Select an RI type.

   The cloud platform provides various RI types for you to choose from based on your application scenarios.

10. Filter for RI specifications.

    Set flavor, OS, term, offering class, and payment option to search for the target RI specifications.

    Table 1 shows specifications parameters.

    Table 1 RI attributes

    Parameter	Description
    Region or AZ	Regional RI: indicates an RI purchased in a region, without an AZ specified. Capacity reservations are not supported for regional RIs. Zonal RI: indicates an RI purchased with an AZ specified. Capacity reservations are supported for zonal RIs.
    Flavor	When purchasing a regional RI, ensure that the ECS series and vCPU/memory ratio specified in the RI are the same as those of the target pay-per-use ECS. When purchasing a zonal ECS, ensure that the flavor specified in the RI is the same as that of the target pay-per-use ECS.
    OS	The OS of the ECS to be bought, which must match the OS specified in your RI. For example, if you want to use a Linux RI, select a Linux public or private image when purchasing an ECS.
    Term	The service duration of an RI. A year is defined as 31,536,000 seconds (365 days).
    Offering Class	Standard: Certain attributes, such as the ECS size can be modified during the term. However, the ECS type cannot be changed.
    Payment Option	No upfront

11. Select specifications.

    The cloud platform provides various RI types for you to choose from based on your application scenarios. On the Buy RI page, view released RI types and specifications.

    Effective Rate: amortized hourly costs of the RI, which is equivalent to the total cost (including any upfront payment) of the RI over the entire term divided by the total number of hours over the entire term. (Effective rate = Total cost of the RI/Entire term of the RI)

    Upfront Price: fee that needs to be paid before you purchase an RI.

    Hourly Rate: amortized hourly costs of the RI, which is equivalent to the difference between the total cost of the RI and the upfront payment divided by the total number of hours over the entire term (Hourly rate = Total cost of the RI – Upfront payment/Entire term of the RI)

12. Specify an RI name.

    The name can be customized. It can contain 1 to 128 characters, which can only be letters, digits, underscores (_), and hyphens (-).

13. Set the number of RIs to be purchased.
    • Quantity: The system displays the number of RIs that you can purchase.
    • Total Normalization Factors: measures the ECS size flexibility. The value is determined based on the specifications of the RI to be purchased.
    • Total Upfront Price + Pay-per-use Price: The price to be paid for consists of the total upfront price and the pay-per-use price. The total upfront price is a product of the upfront fee per RI and the number of RIs. The pay-per-use price is a product of the pay-per-use fee per RI and the number of RIs.

      For details, click Pricing details.

14. Click Next.

    To learn more about the price, click Pricing details.

15. On the page for you to confirm RI specifications, view details and submit the request.

    After verifying the configurations and price, click Submit and pay for the order as prompted.

16. Return to the RI list as prompted and view the purchased RI.

Follow-up Operations

• Purchase a pay-per-use ECS that matches an RI.
  Locate the target RI and click Buy ECS in the Operation column. The system automatically switches to the page for purchasing ECSs, and the specifications of the ECSs selected by default are the same as those specified in the RI.

  

  • If the OS of the target ECS does not match the OS specified in the RI, or the target ECS is not billed on a pay-per-use basis, the RI cannot be used. When the attributes of the ECS match those of the RI, including the ECS series and vCPU/memory ratio, the ECS automatically benefits from the billing discount offered by the RI.
• Check the usage of RIs.
  1. On the Reserved Instance page, select the target RI.
  2. Check that the selected RI is displayed at the bottom of the RI list.
     Figure 1 Selected RI
     
  3. Expand the RI details.
     Figure 2 RI details
     
  4. In the RI details area, click View RI Utilization in the RI Usage row to go to Cost Center and view the RI utilization.
     Figure 3 RI utilization