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FAQ about preemptible instances

Last Updated: Sep 14, 2018

About release

My account is not overdue. Why is my preemptible instance released?

During the hour of use, if the market price at any time point goes higher than your bid or the ECS resources supply changes, your preemptible instance is released automatically.

What notifications are issued when an instance is released?

When a preemptible instance is released because its market price or supply changes, the instance enters the Pending Release status. Then, the instance is released in about five minutes. Call the DescribeInstances interface for the OperationLocks information or use instance metadata, to check whether an instance is in the Pending Release status.

Is data backed up automatically after a preemptible instance is released?

No. If you are not using a preemptible instance, we recommend that you create snapshots to back up your data and environment, and then release the instance. You can purchase a preemptible instance at any time.

I have set time for automatic release. Can I cancel or change the time?

Yes. You can cancel the timed release setting at any time before a preemptible instance is released automatically. A preemptible instance is automatically released because of rise in the market price or change in the resources supply.

About price and charge

Can I convert a preemptible instance to a Subscription instance?

No.

Which resources does the preemptible instance price apply to?

The preemptible instance price applies to the instance type only. Other resources, including system disks, data disks, and network bandwidth, have the same prices as those for Pay-As-You-Go instances.

How do I bid for a preemptible instance?

When creating a preemptible instance, you must set the maximum hourly price you are willing to pay for the expected instance type, which is your bid. When your bid is higher than the current market price, your instance runs. You pay the market price for the preemptible instance.

How do market price and my bid relate to each other?

The preemptible instance runs only when your bid is higher than the current market price. If your bid is lower than the market price, the preemptible instance does not run, or the currently running instance will be released. No matter how high your bid is, you are billed for the preemptible instance according to the market price.

I have started several preemptible instances simultaneously. Are they getting charged at the same rate?

Yes.

During the first hour of my preemptible instance, does the market price fluctuation influence my payment?

No. The market price of a preemptible instance is determined at the beginning of each hour and is effective for that particular hour.

Can I view the current market price before purchasing a preemptible instance?

No. This feature will be available to you when you can create a preemptible instance in the ECS console.

Can I view the price history of a preemptible instance type? If yes, how can I view it?

Yes. Currently, you can call the DescribeSpotPriceHistory interface to query historical prices.

Do I have to pay for a stopped preemptible instance?

Yes. Billing of a preemptible instance continues even though you have stopped it in the ECS console. If you are not using a preemptible instance, we recommend that you create snapshots to back up your data and environment, and then release the instance. You can purchase a preemptible instance at any time.

About limits

How many preemptible instances can I purchase?

The quota unit of preemptible instances is vCPU. When creating a preemptible instance, you can view the current quota after selecting instance type.

You need to open a ticket to apply for the permission of purchasing preemptible instances. A newly-authorized account has the quota of at least 50 vCPUs, and the quota increases along with the account level. For more information, see Limits.

Can I apply for a higher quota? If yes, how to apply?

Yes. You can open a ticket to apply for a higher quota.

Can I change the instance type of a preemptible instance?

No.

Which ECS instance type families are available for preemptible instances?

Preemptible instances and Pay-As-You-Go instances share the same instance type families. Some instance types may be unavailable because of short supply. In this case, you can purchase other instance types.

In which regions can I purchase preemptible instances?

Preemptible instances are available in all regions. If preemptible instances are unavailable in a region because of shortage of resources, you can try in other regions.

How to create a preemptible instance?

You can create a preemptible instance using the CreateInstance or RunInstances interface.

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