Spot Pricing ECSs

Concept

Huawei Cloud sells available computing resources at a discount. The price changes in real time depending on market demands. This is the spot pricing billing mode.

An ECS billed in spot pricing billing mode is a spot ECS.

In spot pricing billing mode, you can purchase and use ECSs at a discount price. A spot ECS performs as well as the ECSs with the same specifications in other billing modes. However, when inventory resources are insufficient, or the market price increases and exceeds your expected price, the system will automatically release your ECS resources and reclaim the ECSs. Compared with pay-per-use and yearly/monthly ECSs, spot ECSs offer the same level of performance while at lower costs.

Working Rules

The market price for the ECSs of a certain flavor fluctuates due to supply-and-demand changes. You can purchase and use spot ECSs at a low market price to reduce computing costs.

When purchasing a spot ECS, you are required to set the maximum price you are willing to pay for a specified flavor. A higher price ensures a greater success rate for you to purchase such an ECS.

If the maximum price is greater than or equal to the market price and the inventory resources are sufficient, the spot ECS can be purchased and will be billed at the market price.
If the maximum price is less than the market price, the spot ECS cannot be purchased.

After purchasing a spot ECS, you can use it like using the ECSs in other billing modes. However, the system will periodically compare the maximum price with the market price and check the inventory resources.

If the maximum price is greater than or equal to the market price and the inventory resources are sufficient, you can continue using the ECS.
If the maximum price is less than the market price or the inventory resources are insufficient, the system notifies you of releasing the ECS resources (notifications enabled) and automatically deletes the ECS in about 5 minutes.

Figure 1 Lifecycle of a spot ECS
Click to enlarge

Application Scenarios

Suitable workloads
Spot ECSs are suitable for image rendering, stateless web service, gene sequencing, offline analysis, function calculation, batch calculation, sample analysis, CI/CD, and test.

When the market price is higher than the maximum price you are willing to pay or the inventory resources are insufficient, the spot ECSs will be reclaimed. Therefore, back up data when using such ECSs.
Unsuitable workloads
To prevent ECS reclamation from interrupting services, do not use spot ECSs to run workloads requiring long-time operations or high stability.

Notes

Only KVM ECSs support spot pricing payments. For details about supported ECS flavors, see the information displayed on the management console.
The market prices of the ECSs of the same flavor may vary depending on AZs.
Spot ECSs do not support OS change.
Spot ECSs do not support automatic recovery.
Spot ECSs do not support specifications modification.
Spot ECSs cannot be created using a Marketplace image.
Spot ECSs cannot be switched to yearly/monthly ECSs.
Spot ECSs do not support system disk detachment.
When a spot ECS is being reclaimed,
- It cannot be used to create system disk images and full-ECS images. However, data disks of the ECS can be used to create data disk images.
- It cannot be deleted.
By default, the data disks and EIP of a spot ECS will not be released after it is reclaimed. If you want to be notified when a spot ECS is reclaimed so that you can determine whether to manually release data disks and EIP, set a reclaim notification. For details, see "Enabling Reclaim Notifications" in Purchasing a Spot ECS.

Billing Rules

See Spot Pricing (for Spot Instances).

Billing Examples

If the market price is higher than the maximum price you set, the spot ECS is released. The spot ECS is billed based on the market price. Example:
At 08:30, the market price is $0.02 USD/hour, and the maximum price is $0.04 USD/hour. Then, the ECS is billed at $0.02 USD/hour.

At 09:00, the market price is $0.03 USD/hour.

At 10:00, the market price is $0.04 USD/hour.

At 10:30, the market price is $0.05 USD/hour, which is higher than the maximum price. Then, the system notifies the user of ECS releasing.

This ECS is billed in three billing periods.

During 08:30-09:00, the ECS had been running for 30 minutes and it is billed by the second: 0.02/3600 x 30 x 60 = $0.01 USD.

During 09:00-10:00, the ECS had been running for 1 hour and it is billed at the market price at 09:00, which is $0.03 USD ($0.03 USD/hour x 1 hour = $0.03 USD).

During 10:00-10:30, the ECS had been running for 30 minutes and it is billed by the second: 0.04/3600 x 30 x 60 = $0.02 USD.

The total price is $0.06 USD for the running duration of 2 hours.
If inventory resources are insufficient, the system releases a price ECS and bills it based on the market price. Example:
At 08:30, the market price is $0.02 USD/hour, and the maximum price is $0.06 USD/hour. Then, the ECS is billed at $0.02 USD/hour.

At 09:00, the market price is $0.03 USD/hour.

At 10:00, the market price is $0.04 USD/hour.

At 10:30, the market price is $0.05 USD/hour. Although the market price is lower than the maximum price, the system releases this ECS due to insufficient inventory resources.

This ECS is billed in three billing periods.

During 08:30-09:00, the ECS had been running for 30 minutes and it is billed by the second: 0.02/3600 x 30 x 60 = $0.01 USD.

During 09:00-10:00, the ECS had been running for 1 hour and it is billed at the market price at 09:00, which is $0.03 USD ($0.03 USD/hour x 1 hour = $0.03 USD).

During 10:00-10:30, the ECS had been running for 30 minutes and it is billed by the second: 0.04/3600 x 30 x 60 = $0.02 USD.

The total price is $0.06 USD for the running duration of 2 hours.

Purchasing a Spot ECS

You can purchase a spot ECS on the management console or by calling APIs.

For instructions about how to purchase a spot ECS on the management console, see Purchasing a Spot ECS.
For instructions about how to purchase a spot ECS by calling APIs, see Creating an ECS.

Reclaiming an ECS

Huawei Cloud may reclaim and terminate your spot ECS at any time. A spot ECS that is being reclaimed cannot be used to create images.

An ECS may be reclaimed due to:

Higher market price than the maximum price you are willing to pay
Insufficient inventory resources
- If a spot ECS is reclaimed within the first hour after it is provisioned, the spot ECS is not billed.
- In the first settlement period (in hours) of a spot ECS, the spot ECS is billed, regardless of whether it is started or not.
- It takes 5 minutes to reclaim a spot ECS. If during that 5 minutes, the spot pricing hour is exceeded, any time in excess of that hour will be billed at the new market price.
- During the running of a spot ECS, its price is updated once an hour. After a spot ECS is restarted, or it is stopped and then started, it is billed at the market price when the ECS starts.

Back up data on spot ECSs. Before the system reclaims your spot ECSs, it will notify you of the release if notifications are enabled. To enable notifications, see Purchasing a Spot ECS.