I have several instances in a specific region of EC2 using EBS as well. Recently, I've started noticing some error logs caused by the Managed Platform Update. Here are the logs:
February 8, 2024 16:34:30 (UTC-3) INFO Deployment failed. Terminating new instances and temporary Auto Scaling group.
February 8, 2024 16:34:29 (UTC-3) ERROR Failed to deploy configuration.
February 8, 2024 16:34:29 (UTC-3) ERROR Service:AmazonCloudFormation, Message:Stack named 'awseb-e-auhbch5mnp-immutable-stack' aborted operation. Current state: 'CREATE_FAILED' Reason: The following resource(s) failed to create: [AWSEBEIP].
February 8, 2024 16:34:29 (UTC-3) ERROR Creating EIP failed Reason: Resource handler returned message: "The maximum number of addresses has been reached. (Service: Ec2, Status Code: 400, Request ID: c0f652a6-9c94-4d44-9077-ebf7f968c74a)" (RequestToken: 748926b3-cc81-1edf-d384-0ae944a36a0d, HandlerErrorCode: GeneralServiceException)
February 8, 2024 16:33:58 (UTC-3) INFO Immutable deployment policy enabled. Launching one instance with the new settings to verify health.
February 8, 2024 16:33:50 (UTC-3) INFO Environment update is starting.
February 8, 2024 16:33:49 (UTC-3) INFO Managed platform update is in-progress.
The issue is that I have 5 instances in the region (which seems to be the limit), but I don't want to delete any of them. I saw that it was possible to set the instances to deploy in "All at Once" mode, and that should be enough to prevent it from creating a new Auto Scaling Group and temporary instance, but nothing changed.
It still prints "immutable deployment policy enabled. Launching one instance with the new settings to verify health." when starting the update, even with the settings disabled. Did I misunderstand something, or is that really the case? Is the only solution to have only 4 instances per region to avoid the problem?