要約

This article provides guidance on how to adjust the fallback timeout to a regular EC2 instance when using AWS Spot configuration and recommends an approach to finding a well-balanced setup that does not affect the delivery of build results.

環境

• Bamboo
• Elastic Agents

診断

You could observe the warning below inside the Support Zip:

[elastic-pool-2-thread-5] [RemoteEC2InstanceImpl] Spot request sir-kx86nj9h state is cancelled after 61 seconds, falling back to a regular instance.

The warning indicates that a request to create a Spot Instance (with request ID sir-kx86nj9h) was cancelled because it was not fulfilled within the expected time frame (in this case, 61 seconds), given that the spot request was not completed, the system tries to provision a regular (on-demand) EC2 instance as a fallback. 

原因

Bamboo operates on a bidding basis for Spot instances, but does not take dynamic costs into account, and is subject to the time it takes for requests to update. If a transition from BIDDING to IDENTIFIED is not confirmed by AWS within the designated fallback period, Bamboo will automatically switch to a standard on-demand instance.

Users can configure Elastic Bamboo to buy a spot instance of a particular type and fall back to a regular instance after a set amount of time if no instances are available.

As described in:

• Configuring Elastic Bamboo - EC2 spot instances

In this case, the fallback time is 1 minute which is 60 seconds and Bamboo falls back to normal EC2 instance selection after 61 seconds.

ソリューション

To address the issue, follow the steps below:

1. Navigate to Bamboo Configuration
2. Select Spot Instances
3. Adjust the "Fallback to a regular instance after" property value. It is advisable to increment the value in small amounts
4. Monitor the creation of Bamboo's Elastic Agent after each adjustment
5. Continue the adjustments until you achieve a configuration that is balanced and does not negatively impact your build results delivery.

An example of the configuration page is shown below: