Custom Presto Configuration
When using a Custom Configuration, CloudFormation update stack may not update the Presto configuration after you’ve made changes to content in your configuration zip. This usually occurs if the updated configuration zip file name is the same as previously used. Try renaming the package and rerunning the CloudFormation update stack. We recommend including a version name within the file name to avoid any complications when updating your configurations.
When using a Custom Configuration, CloudFormation update stack may fail. This is often because the configuration zip file has an invalid directory structure. Be sure to double check the content and structure of your configuration package. When troubleshooting, try adding incremental updates to the configuration package until it fails. That will help you find the cause.
Placement Groups Capacity
When using the cluster placement group type, you can encounter insufficient capacity errors. To avoid such a setback consider the following suggestions.
Single Launch Request
It is recommended that you launch the number of instances that you need in the placement group in a single launch request, and that you use the same instance type for all instances in the placement group. If you try to add more instances to the placement group later, or if you try to launch more than one instance type in the placement group, you increase your chances of getting an insufficient capacity error.
Start. Stop. Relaunch.
If you receive a capacity error when launching an instance in a placement group that already has running instances, stop and start all of the instances in the placement group, and try the launch again. Restarting the instances may migrate them to hardware that has the capacity for all the requested instances.
Please refer to the following link for more on placement groups and their rules and limitations.