i am running aws cloudwatch with pretty basic configuration, but it completely ignores the retention_in_days setting.

{
  "agent": {
    "metrics_collection_interval": 10,
    "logfile": "/tmp/test.log"
  },
  "logs": {
    "logs_collected": {
      "files": {
        "collect_list": [
          {
            "file_path": "/var/log/messages",
            "log_group_name": "TEST",
            "log_stream_name": "{instance_id}-{local_hostname}-/var/log/messages",
            "retention_in_days": 30,
            "timezone": "UTC"
          }
        ]
      }
    }
  }
}

Starting the agent like this:

sudo /opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent-ctl -a fetch-config -s -c file:/tmp/config -m ec2

I can see the loggreap created and logstream inside it. Everything looks ok except that retention on the loggroup is set to never expire. I cant figure this one out. What is missing? Also tried downloading the latest agent just to make sure, but still doesnt work. Thanks