AWS ECS: How to list Fargate containers? - amazon-web-services

Question

I need to obtain details on a Fargate container running for a task in an AWS ECS cluster.
The information I retrieve using the AWS CLI matches what I see in the AWS Console, e.g.
$ aws ecs list-clusters
{
"clusterArns": [
"arn:aws:ecs:us-east-1:<my account ID>:cluster/<cluster short name>"
]
}
$ aws ecs list-services --cluster "arn:aws:ecs:us-east-1:<my account ID>:cluster/<cluster short name>"
{
"serviceArns": [
"arn:aws:ecs:us-east-1:<my account ID>:service/<cluster short name>/<service short name>"
]
}
$ aws ecs list-tasks --cluster "arn:aws:ecs:us-east-1:<my account ID>:cluster/<cluster short name>"
{
"taskArns": [
"arn:aws:ecs:us-east-1:<my account ID>:task/<cluster short name>/<task ID>"
]
}
Now, I am looking at the container running for the task shown above: It is running, it is healthy, everything seems fine.
However, when I try to obtain container details using the AWS CLI, I get an empty result:
$ aws ecs list-container-instances --cluster "arn:aws:ecs:us-east-1:<my account ID>:cluster/<cluster short name>"
{
"containerInstanceArns": []
}
I'm completely puzzled. I have double / triple / quadruple-checked what I'm doing, everything seems fine - not exactly rocket science, anyway...
My best guess at this stage is that list-container-instances only supports EC2, not Fargate instances, but TBH, that feels way off - like a massive 'blind spot' in the AWS API, i.e. an AWS resources not properly supported by AWS itself.
My question: How do I list AWS ECS Fargate container instances using the AWS CLI ?
Some additional internals (these shouldn't matter to the problem at hand, but might still help to give some context):
The Fargate container is running a service inside private subnet only accessed by the backend application of my current project. In order to configure that service, I start a jump host in a public subnet in the same VPC as the private subnet and create an SSH tunnel from my local dev machine over that jump host to the Fargate container. In order to create that SSH tunnel, I need the container's private IP address.
From what I understand, these seems a fairly common approach. Things work fine when doing them on the fly , i.e. copying the private IP address from the AWS Console to the Terminal. However, for long term DevOps production, I need to get the private IP address in a script using the AWS CLI. HTH.