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Since TeamCity 2017.1, when launching Amazon EC2 instances, TeamCity tags all the resources (e.g. volumes and network adapters) associated with the created instances, which is important when evaluating the overall cost of an instance (taking into account the storage drive type and size, I/O operations (for standard drives), network (transfers out), etc.
Sharing single EBS instance between several TeamCity servers
As mentioned above, TeamCity tags every instance it launches with "teamcity:TeamcityData" tag that represents server, cloud profile and source (AMI or EBS-instance). So, in case when several TeamCity servers tries to use the same EBS instance, the second one will see message "Instance is used by another TeamCity server. Unable to start/stop it". If you are sure that no other TeamCity servers are working with this instance, you can delete the "teamcity:TeamcityData" tag and the instance will become available for all TeamCity servers again.
New instance types
Since Amazon doesn't provide a robust API method to retrieve all instance types, Amazon integration relies on periodical update of AWS SDK to make new instance types available.
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