Reserved instances are coupons that can offset the bills of pay-as-you-go Elastic Compute Service (ECS) instances, excerpt for preemptible instances. You can create reserved instances to provision resources to ensure stable resource supply. This topic describes the payment options and billing rules of reserved instances.
Payment options
Reserved instances must be used in combination with pay-as-you-go instances. Reserved instances can be matched to pay-as-you-go instances to cover charges for computing resources (not for network and storage resources), based on the computing power of the reserved instances. The computing power is calculated by using the following formula: Normalization factor of an instance type × Instance quantity. For more information, see Overview.
Reserved instances support the following payment options:
All Upfront: Full payment is required upfront at the time of purchase, with no other costs or additional hourly charges incurred throughout the term.
Partial Upfront: Partial payment (about 50% of the full amount) is required upfront at the time of purchase, and you are billed an hourly rate for every hour within the term.
No Upfront: No upfront payment is required at the time of purchase, and you are billed an hourly rate for every hour within the term.
NoteYour ECS usage determines whether you can use the No Upfront payment option. To use the No Upfront payment option, submit a ticket.
Partial Upfront and No Upfront reserved instances are billed in 1-second increments. Bills are generated hourly and paid monthly. For more information, visit the Pricing tab on the Elastic Compute Service product page. When the total payable amount on the monthly bill reaches USD 1,000, USD 1,000 is automatically deducted from your account balance.
Billing rules
A reserved instance takes effect immediately after it is purchased, and matches eligible pay-as-you-go instances on an hourly basis to offset the bills of the pay-as-you-go instances. You are charged based on the payment option that you selected regardless of whether the reserved instance is matched to pay-as-you-go instances. The All Upfront option is the most cost-effective one among the payment options for reserved instances.
For information about how a reserved instance is matched to pay-as-you-go instances, see Match between reserved instances and pay-as-you-go instances.
A reserved instance takes effect and is billed starting on the hour of your purchase. The reserved instance expires at 24:00:00 on the expiration date. For example, if you purchase a reserved instance with a one-year term at 22:45:00 on May 1, 2020, the reserved instance takes effect and is billed starting 22:00:00 on May 1, 2020. The reserved instance expires at 00:00:00 on May 2, 2021. If you purchase a reserved instance and have pay-as-you-go instances that match the attributes of the reserved instance, the reserved instance is applied to offset the bills generated for matched pay-as-you-go instances starting from the hour of 22:00 to 23:00 on May 1, 2020 until the reserved instance expires.
Configure Specify Effective Time. Billing for a reserved instance starts at the effective time that you specify for the reserved instance.
Renewal
Reserved instances support two renewal methods: manual renewal and auto-renewal. Select a renewal method based on the lifecycle state of your reserved instance:
Manual renewal
You can manually renew a reserved instance in the ECS console anytime before the reserved instance expires.
You can manually renew reserved instances for one month, one year, or three years. After a reserved instance is renewed, the new billing cycle begins on the original expiration date.
After reserved instances are split or merged or have their scopes changed, new reserved instances are generated and can be renewed.
Auto-renewal
If auto-renewal is enabled for a reserved instance, the reserved instance is automatically renewed before it expires. You can enable this feature for reserved instances to prevent the reserved instances from being automatically released.
When you enable auto-renewal, take note of the following items:
If you manually renew a reserved instance before it is automatically renewed, the auto-renewal operation is not performed during the current billing cycle.
If you manually renew a reserved instance before the auto-renewal payment is deducted, the system renews the reserved instance based on its new expiration date.
After you enable auto-renewal for a reserved instance, the system deducts a renewal payment from your account to renew the reserved instance before it expires. Maintain a sufficient account balance. The following list describes the system operations involved in auto-renewal:
Nine days before your reserved instance expires, the system attempts to deduct the renewal payment for the first time.
If the first deduction attempt fails, the system attempts to deduct the renewal payment once every day until the payment is deducted or until the reserved instance expires.