workers.json

{
    "Linux":{
        "Ubuntu_16_04_64":{
            "image": "my_image:16.04",
            "properties":{
                "tasks": ["build"]
            },
            "workers": 3
        },
        "Ubuntu_14_04_64":{
            "image":"my_image:14.04",
            "proprties":{
                "tasks": ["build"]
            },
            "workers": 0
        }
    }

}