Enabling Container insights on Rack V2

What is the good approach to enable Container insights on the ECS Cluster of a V2 Rack?
My concern is how to enable Instance Level Insights?

Because I don’t like to use AWS cli to modify the Convox Rack, I tried the agent approach to deploy the amazon/cloudwatch-agent the Convox way, like the datadog agent example in the V2 docs.

The agent seems to be running

convox apps
APP                  STATUS   RELEASE
cloudwatch-agent     running

but no EC2 metrics show up in the Cloudwath Container Insights console (e.g. ECS Instances CPU Utilization)

It might be because the Necessary IAM roles and policies are missing, but how to set those up the Convox way (i.e. no aws cli required)?

Thanks

Here is the convox.yml used to deploy the agent:

services:
  cloudwatch-agent:
    agent: true
    image: amazon/cloudwatch-agent:latest
    privileged: true
    scale:
      cpu: 128
      memory: 64
    volumes:
      - /sys/fs/cgroup/:/rootfs/sys/fs/cgroup/
      - /cgroup/:/rootfs/cgroup/
      - /proc/:/rootfs/proc/
      - /dev/:/rootfs/dev/