{
    "Description": "A template that provides a single server instance.",
    "Parameters": {
        "server-size": {
            "default": "1GB Standard Instance",
            "description": "Server size",
            "type": "String",
            "constraints": [
                {
                    "allowed_values": [
                        "512MB Standard Instance",
                        "1GB Standard Instance",
                        "4GB Standard Instance",
                        "8GB Standard Instance"
                    ],
                    "description": "Must be a valid server size."
                }
            ]
        },
        "key_name": {
            "description": "Keypair name for SSH access to the server",
            "required": true,
            "type": "String"
        },
        "server_name": {
            "default": "My server",
            "description": "My server",
            "type": "String"
        }
    },
    "ParameterGroups": [
        {
            "label": "Parameter groups",
            "description": "My parameter groups",
            "parameters": [
                "param_name-1",
                "param_name-2"
            ]
        }
    ]
}