When you purchase an elasticity assurance, you must specify attributes such as instance type and zone. Alibaba Cloud reserves resources that have matching attributes in a private pool for your use to create pay-as-you-go instances.

Background information

When you purchase an elasticity assurance, you must pay a small assurance fee to gain guaranteed access to resources. After you use the reserved capacity in the associated private pool to create pay-as-you-go instances, you are charged for the instances on an hourly basis at the pay-as-you-go rate. The actual price of an elasticity assurance is displayed on the elasticity assurance buy page.

Procedure

  1. Log on to the ECS console.
  2. In the left-side navigation pane, choose Instances & Images > Resource Assurance.
  3. In the top navigation bar, select a region.
  4. In the upper part of the Resource Assurance page, click the Elasticity Assurance tab.
  5. Click Purchase Elasticity Assurance.
  6. In the Query Solutions step, configure parameters and click Next: Confirm Information.
    1. Configure the attributes of the elasticity assurance.
      An elasticity assurance can be used to create only pay-as-you-go instances that match the attributes of the elasticity assurance, such as instance type and zone. The following table describes parameters used to specify the attributes of an elasticity assurance.
      Parameter Description
      Region and Zone The region and zone in which to reserve resources. In the Recommended Solution section, other zones may be recommended based on resource availability. The zone in the solution that you select is used.
      Instance Type The instance type for which to reserve resources. In the Recommended Solution section, other alternative instance types may be recommended based on resource availability. The instance type in the solution that you select is used.
      Reserved Quantity The number of instances for which to reserve resources.
      Billing Method The billing method of instances. After an elasticity assurance is purchased, you can use the reserved capacity in the associated private pool to create only pay-as-you-go instances.
      Effective At The time at which the elasticity assurance takes effect. The end time of the validity period cannot be specified but is automatically changed with the specified Duration value.
      Duration The validity period of the elasticity assurance. You can select a duration of one month up to five years. The durations available for selection are displayed on the elasticity assurance buy page.
    2. View and select a solution in the Recommended Solution section.
      The recommended solutions may deliver optimal performance, be backed by the most sufficient supply of resources, or provide multi-zone disaster recovery. You can select the solution that best suits your needs. ea-recommended
      Note If no recommended solutions are available or if the recommended solutions cannot meet your requirements, you can submit a ticket.
    3. Configure the private pool.
      After an elasticity assurance is purchased, Alibaba Cloud reserves resources that match the attributes such as instance type and zone of the elasticity assurance in a private pool.
      Parameter Description
      Private Pool Type The private pool type. Valid values: Open and Targeted.
      • You can use one of the following methods to specify which open private pool to use:
        • Specify the ID of an open private pool to use when you create instances.
        • If tag matching is enabled for an open private pool, you can add the tags of the associated elasticity assurance when you create instances to use the open private pool.
        • If tag matching is not enabled for one or more open private pools and you select Open as the private pool type without specifying a private pool ID, the system selects for you an open private pool whose associated elasticity assurance does not have tags.
      • To use a targeted private pool to create instances, you must manually specify the ID of the private pool.

      We recommend that you prepare a number of open and targeted private pools based on your business types. For example, you can prepare targeted private pools dedicated to key business. For more information, see Private Pool.

      Private Pool Name The name of the private pool. The name must be 2 to 128 characters in length and can contain letters, digits, colons (:), underscores (_), periods (.), and hyphens (-). It must start with a letter and cannot start with http:// or https://.
      Description The description of the private pool. Enter an informative description for easy management. The description must be 2 to 256 characters in length and cannot start with http:// or https://.
    4. Add tags.
      You can perform operations such as batch executing O&M tasks and financial sharing based on tags. For more about the use scenarios of tags and how to work with tags, see Overview.
      In addition to common use scenarios, you can use open private pools in a fine-grained manner based on tags. After you add tags to an elasticity assurance, tag matching is automatically enabled for the associated private pool. If you select Open as the private pool type and add the same tags when you create instances, the associated private pool is automatically matched and used.
      Notice After an elasticity assurance takes effect, its associated private pool is always matched based on the tags added when the elasticity assurance was purchased. We recommend that you do not edit the tags of purchased elasticity assurances.
  7. In the Confirm Information step, confirm you configurations, click Purchase, and then complete the payment.
    1. View the parameters in the Overview of Elastic Security section.
    2. Select one or more elastic assurances in the Elastic guarantee splitting section.
      Each elasticity assurance is applicable only to a specific instance type within a specific zone. If you select a solution that includes multiple instance types or zones, the solution is automatically split into multiple elasticity assurances. Select the elasticity assurances that suit your needs.
    3. After you confirm that all configurations are correct, read and select the notes, and then click Purchase.
      Complete the payment as prompted.

What to do next

On the Elasticity Assurance tab, view the elasticity assurance that you purchased. When the elasticity assurance is in the Active state, you can use its associated private pool to create pay-as-you-go instances. For more information, see Use a private pool.