This Node-RED flow allows to wake a My Cloud NAS and put it in standby (hibernate) through Alexa by emulating a WeMo smart plug and executing Wake-on-LAN and HTTP requests. The flow requires the "node-red-contrib-wemo-emulator" package and "wakeonlan" package.

MyCloudAlexa.json

[
    {
        "id": "4f84bfa31ca7adb9",
        "type": "wemo-emulator",
        "z": "42846943.2b4b38",
        "name": "My Cloud",
        "friendlyName": "My Cloud",
        "serial": "23",
        "port": "44023",
        "onTopic": "My Cloud",
        "onPayload": "on",
        "offTopic": "My Cloud",
        "offPayload": "off",
        "x": 120,
        "y": 900,
        "wires": [
            [
                "6ee2d29b0c31bb4b"
            ]
        ]
    },
    {
        "id": "96a298711fd0b42b",
        "type": "exec",
        "z": "42846943.2b4b38",
        "command": "wakeonlan <macaddress>",
        "addpay": "",
        "append": "",
        "useSpawn": "false",
        "timer": "",
        "winHide": false,
        "oldrc": false,
        "name": "Wake",
        "x": 490,
        "y": 900,
        "wires": [
            [
                "a23c813ac7c648e3"
            ],
            [],
            []
        ]
    },
    {
        "id": "6ee2d29b0c31bb4b",
        "type": "switch",
        "z": "42846943.2b4b38",
        "name": "",
        "property": "payload",
        "propertyType": "msg",
        "rules": [
            {
                "t": "eq",
                "v": "on",
                "vt": "str"
            },
            {
                "t": "eq",
                "v": "off",
                "vt": "str"
            }
        ],
        "checkall": "true",
        "repair": false,
        "outputs": 2,
        "x": 310,
        "y": 900,
        "wires": [
            [
                "96a298711fd0b42b"
            ],
            [
                "8698f998c03e744d"
            ]
        ]
    },
    {
        "id": "a23c813ac7c648e3",
        "type": "debug",
        "z": "42846943.2b4b38",
        "name": "",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "false",
        "statusVal": "",
        "statusType": "auto",
        "x": 730,
        "y": 940,
        "wires": []
    },
    {
        "id": "8698f998c03e744d",
        "type": "exec",
        "z": "42846943.2b4b38",
        "command": "curl -sSL -c ~/cookie.dat --header 'Content-Type:application/json' --request POST --data '{\"username\":\"<username>\",\"password\":\"<password base64 encoded>\"}' http://<ipaddress>/nas/v1/auth && curl -sSL -b ~/cookie.dat \"http://<ipaddress>/cgi-bin/system_mgr.cgi?cmd=cgi_shutdown\"",
        "addpay": "",
        "append": "",
        "useSpawn": "false",
        "timer": "",
        "winHide": false,
        "oldrc": false,
        "name": "Hibernate",
        "x": 500,
        "y": 960,
        "wires": [
            [
                "a23c813ac7c648e3"
            ],
            [],
            []
        ]
    }
]