~/deploy_k8s$ ansible-inventory -i hosts --list
{
    "_meta": {
        "hostvars": {}
    }, 
    "all": {
        "children": [
            "master", 
            "ungrouped", 
            "worker"
        ]
    }, 
    "master": {
        "hosts": [
            "78.46.228.236"
        ]
    }, 
    "worker": {
        "hosts": [
            "78.47.184.249", 
            "78.47.31.153", 
            "78.47.47.138"
        ]
    }
}
