I hit an issue while testing ECS Managed Instance, so here's a quick note for future reference.

ECS Exec Fails on a Task Container Running on ECS Managed Instance in a Public Subnet

If you deploy this setup in a public subnet without any special network configuration and run the Exec command, you'll get the following error:

An error occurred ( TargetNotConnectedException ) when calling the ExecuteCommand operation: The execute command failed. TargetNotConnected: ecs:ecs-task_xxxxxxxxxxxxxxxx is not connected.

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Network Considerations for ECS Managed Instance

The blog post linked below covers this in detail, but it appears that with ECS Managed Instance, you cannot assign a public IP to a task using assignPublicIp=ENABLE .

https://zenn.dev/gsk9999/articles/0da047d2cc3b59

When Task Instances Are Placed in a Public Subnet

Here is what you can do:

Create a VPC Endpoint

I confirmed this works with my own testing.…