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Spot Instance

Last updated:2021-08-04 11:26:31

Spot Instance is a new billing mode that aims at providing cost-effective computing services and saving your usage costs. Spot Instance allows you to purchase an instance with the same performance as a Pay-As-You-Go instance at a discount of 10% to 90%.

The system judges your bid dynamically based on indicators such as the market price and instance inventory, and provides cost-effective cloud resources. For stateless business with high tolerance to interruption, Spot Instance can help greatly save costs of using cloud resources.


How it works


The most important system evaluation parameters for a Spot Instance are the inventory and real-time market price.

The selling price of a Spot Instance is changing in real time. In general, it is 10% to 90% of the Pay-As-You-Go price. To purchase a Spot Instance, you must specify the highest bid that you are willing to pay, or use automatic bidding to keep your bid consistent with the real-time market price. If your bid is not lower than the real-time market price and the resource pool has sufficient inventory, you can obtain a Spot Instance.

When the Spot Instance is running, the system automatically detects the resource inventory and market price. Once the resource inventory is insufficient or your bid is lower than the real-time market price, the system will send an alert to you and automatically release the instance after 10 minutes. You can also manually release a Spot Instance at any time.

A Spot Instance will not be automatically released in the first hour after it is allocated to you, even if your bid is lower than the market price or the resource inventory is insufficient during this period. The system ensures that your Spot Instance runs for at least one hour before it is released.

Discount range

The discount of Spot Instances is only provided for two computing resources: CPU and memory. No discount is provided for network and storage resources. The following table gives an example.


The discount is based on the Pay-As-You-Go price and changes with the market supply and demand. The fluctuation will not be great except for sudden burst of purchases.



A Spot Instance is billed based on the duration that you explicitly hold the instance, which is accurate to seconds. When you bid for a Spot Instance, the system allocates a Spot Instance if the conditions are met and starts the billing. When your bid is lower than the market price, the system will send an alert and automatically release the instance after 10 minutes. During the period when you hold the instance, the system will charge you based on the market price, and the bill will be issued every hour on the hour.


Spot Instances are applicable to the business with high fault tolerance and high tolerance to interruptions to achieve the highest cost-effectiveness.

Typical scenarios include:

  • Big data analytics
  • Image and media rendering
  • Batch computing
  • Web services with load balancing enabled
  • Financial risk analysis
  • Service tests
  • Geospatial survey and analysis
  • DNA sequencing

We recommend that you do not use Spot Instances for business that requires high stability, is stateful, or has poor tolerance to interruptions.


Up to 20 Spot Instances can be created for a single account in each region. Spot Instances do not support the following features:

  • Change of configurations and instance types
  • Change to prepaid instances
  • No Fees Upon Shutdown
  • System reinstallation

Purchase a Spot Instance

You can purchase a Spot Instance by using one of the following methods:

  • Use the console. For more information, see Create a Spot Instance.
  • Use the API. For more information, see the description of the RunInstances operation.

Reclaim a Spot Instance

The system may automatically reclaim a Spot Instance in use due to the following factors:

  • Market price: The market price of a Spot Instance will change at any time. When your initial bid (the highest price that you are willing to pay) is lower than the market price, your Spot Instance will be marked Released by the system.
  • Inventory: When the instance inventory in the resource pool is insufficient, a Spot Instance may be released. If multiple users provide the same bid, the system will randomly release some Spot Instances to expand the inventory.

No matter which factor causes the Spot Instance release, the system will send an alert in a text message, an email, and an internal message to you 10 minutes before actual release. Once the release alert is received, the Spot Instance will be irreversibly released, and you need to back up the data before the instance is released. We recommend that you regularly back up the data for a better experience.

In addition to text messages, emails, and internal messages, you can call the DescribeInstances operation to obtain the release information about a Spot Instance. You can check the SpotRecyclingTime parameter in InstancesSet.

For Kingsoft Cloud Spot Instances, the Stable One Hour service is provided. In the first hour after the instance is created, the system will not release the instance even if the market price increases or the inventory is insufficient.


FAQs about Spot Instance

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