Each onpremise server needs to have their own namespace - How to do it?

Hello everyone!

I am new in AWS so sorry if the question can sound so simple or stupid. But I am blocked with that. I'm trying with cloudwatch get all the possible metrics from our on-premise linux servers. With wizard tool we can do that (https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/create-cloudwatch-agent-configuration-file-wizard.html). The problem is that I need to split the metrics of each server in different namespaces (each server needs to have their own namespace). And here is the issue. I did not find the form of do it.

I read the documentation of AWS Cloudwatch, and I found this solution for create namespaces (adding this code line in the json config file - /opt/aws/amazon-cloudwatch-agent/bin/config.json):

{
  "metrics": {
    "namespace": "Development/Product1Metrics",
   ......
   },
} 

https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/CloudWatch-Agent-Configuration-File-Details.html (Refeering to CloudWatch agent configuration file: Metrics section).

The complete json config file is the next one:

{
  "agent": {
    "metrics_collection_interval": 60,
    "run_as_user": "root",
    "region": "eu-central-1"
  },
  "logs": {
    "logs_collected": {
      "files": {
        "collect_list": [
          {
            "file_path": "",
            "log_group_name": ".",
            "log_stream_name": "{hostname}",
            "retention_in_days": -1
          },
          {
            "file_path": "",
            "log_group_name": ".",
            "log_stream_name": "{hostname}",
            "retention_in_days": -1
          }
        ]
      }
    }
  },
  "metrics": {
    "namespace": "DEV/ONPREMISE",
    "metrics_collected": {
      "collectd": {
        "metrics_aggregation_interval": 60
      },
      "cpu": {
        "measurement": [
          "cpu_usage_idle",
          "cpu_usage_iowait",
          "cpu_usage_steal",
          "cpu_usage_guest",
          "cpu_usage_user",
          "cpu_usage_system"
        ],
        "metrics_collection_interval": 60,
        "resources": ["*"],
        "totalcpu": true
      },
      "disk": {
        "measurement": ["used_percent"],
        "metrics_collection_interval": 60,
        "resources": ["*"]
      },
      "diskio": {
        "measurement": [
          "io_time",
          "write_bytes",
          "read_bytes",
          "writes",
          "reads"
        ],
        "metrics_collection_interval": 60,
        "resources": ["*"]
      },
      "mem": {
        "measurement": ["mem_used_percent"],
        "metrics_collection_interval": 60
      },
      "net": {
        "measurement": [
          "bytes_sent",
          "bytes_recv",
          "packets_sent",
          "packets_recv"
        ],
        "metrics_collection_interval": 60,
        "resources": ["*"]
      },
      "netstat": {
        "measurement": ["tcp_established", "tcp_time_wait"],
        "metrics_collection_interval": 60
      },
      "statsd": {
        "metrics_aggregation_interval": 60,
        "metrics_collection_interval": 10,
        "service_address": ":8125"
      },
      "swap": {
        "measurement": ["swap_used_percent"],
        "metrics_collection_interval": 60
      }
    }
  }
}

And after that, I used the command: sudo /opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent-ctl -a append-config -m onPremise -c file:/opt/aws/amazon-cloudwatch-agent/bin/config.json.

This is the output of the command:

****** processing amazon-cloudwatch-agent ******
Got Home directory: /root I! Set home dir Linux: /root I! SDKRegionWithCredsMap region: eu-central-1 Successfully fetched the config and saved in /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.d/file_config.json.tmp
Start configuration validation...
2023/06/01 09:37:38 Reading json config file path: /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.json ...
2023/06/01 09:37:38 Reading json config file path: /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.d/file_config.json ...
2023/06/01 09:37:38 Reading json config file path: /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.d/file_config.json.tmp ...
2023/06/01 09:37:38 Reading json config file path: /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.d/ssm_AmazonCloudWatch-linux ...
2023/06/01 09:37:38 I! Valid Json input schema.
I! Detecting run_as_user...
Got Home directory: /root
No csm configuration found.
Under path : /logs/ | Info : Got hostname mdk02 as log_stream_name
Configuration validation first phase succeeded
/opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent -schematest -config /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.toml
Configuration validation second phase succeeded
Configuration validation succeeded

Seems that does not exist any error

But when I update cloudswatch in the eu-central-1 region, I can not see nothing with the namespace name "DEV/ONPREMISE": https://imgur.com/a/qeepamK

Thanks in advance to everyone can help! :)