Ping host to see if it's up. If it's not, use Pushbullet to send you a notification.

sia_ping.py

#!/usr/bin/python

import subprocess

# Follow https://docs.pushbullet.com/#api-quick-start to get free token
TOKEN = ""
HOST_ADDRESS = ""
BASE_URL = "https://api.pushbullet.com/v2/"
data = '{"type":"note","title":"Sia","body":"Sia Host is Down!!"}'

try:
    subprocess.check_call(["ping", "-c", "1", HOST_ADDRESS])
except subprocess.CalledProcessError:
    r = subprocess.check_output(["curl", "--header", 'Access-Token: {}'.format(TOKEN), "--header", "Content-Type: application/json",
                     "--data-binary", data, "--request", "POST", '{}pushes'.format(BASE_URL)])

    print r