This is newrelic clouc-config.yml for coreos. https://registry.hub.docker.com/u/uzyexe/newrelic-for-onboot-coreos/

newrelic-for-diskboot-coreos-cloud-config.yml

coreos:
  units:
    - name: newrelic.service
      command: start
      content: |
        [Unit]
        Description=newrelic
        Requires=docker.service
        After=docker.service
        
        [Service]
        Restart=always
        RestartSec=300
        TimeoutStartSec=10m
        ExecStartPre=-/usr/bin/docker stop newrelic
        ExecStartPre=-/usr/bin/docker rm -f newrelic
        ExecStartPre=-/usr/bin/docker pull uzyexe/newrelic:latest
        ExecStart=/usr/bin/docker run \
                    --rm \
                    --name="newrelic" \
                    --memory="64m" \
                    --memory-swap="-1" \
                    --net="host" \
                    --pid="host" \
                    --env="NEW_RELIC_LICENSE_KEY=YOUR_NEW_RELIC_LICENSE_KEY" \
                    --volume="/var/run/docker.sock:/var/run/docker.sock:ro" \
                    --volume="/sys/fs/cgroup/:/sys/fs/cgroup:ro" \
                    --volume="/dev:/dev" \
                    uzyexe/newrelic
        ExecStop=/usr/bin/docker stop newrelic
        
        [Install]
        WantedBy=multi-user.target