Google Load Balancer

Setup an f1-micro server, copy echo.py, install virtualenv

sudo apt-get update sudo apt-get install python-virtualenv virtualenv -p python3 ~/venv3 source ~/venv3/bin/activate pip install flask

Add to the crontab of root the following:

@reboot /home/gabor/venv3/bin/python /home/gabor/echo.py 5000

TODO: install a more roboust webserver for this or run uwsgi

Create a snapshot of the server Create an image from the snapshot Create an "Instance Template" that can create an instance of f1-micro using the above image.

Create an instance group

Networks Services - create a load balancer that uses the instance group.

examples/load-balancer/web.py

from flask import Flask, request, jsonify
import sys
from datetime import datetime
import socket
import json

app = Flask(__name__)

version = 1

def myconverter(o):
   if isinstance(o, datetime):
       return o.__str__()


@app.route("/")
def hello():
   logfile = '/tmp/echo.log'
   data = {
       'client': request.remote_addr,
       'hostname': socket.gethostname(),
       'port': port,
       'now': datetime.now(),
       'version': version,
   }
   with open(logfile, 'a') as fh:
       fh.write(json.dumps(data, default = myconverter))
       fh.write("\n")
   return jsonify(data)


if __name__ == "__main__":
   if len(sys.argv) < 2:
       exit("Need port number")
   port = int(sys.argv[1])
   app.run(port = port, host='0.0.0.0')

examples/load-balancer/monitor.py

#!/usr/bin/env python

import requests
import time
import sys

url = 'http://10.2.11.5:5000/'

while True:
   #print(time.time())

   try:
       res = requests.get(url, timeout=0.3)
       if res.status_code == 200:
           print(res.content, end="")
       else:
           print("ERROR: {}".format(res.status_code))
   except Exception as e:
       print("EXCEPTION {}".format(e))
   sys.stdout.flush()
   time.sleep(1)