Disclaimer: Any potential CS 695 students, please don't copy this code.
Autoscaling Assignment
Version: 1.0
Author: Diptyaroop Maji, CSE @ IIT-B, MTech-II
Setup: 2 servers on VMs, 1 client in host, 1 monitoring program in host.
Initially, the monitoring program is executed. It boots up server1 (domain schema XML already existing) and monitors its CPU utilization. Now, client is started, which communicates with server (CREATE, GET, UPDATE, DELETE K-V). If server1 CPU utlization exceeds a certain threshold (kept at 80%) for a considerable amount of time, the monitoring program boots up server2 and notifies the client that server1 is overloaded.
On receiving the notification, the client now acts as a load balancer, i.e., disconnects half of its threads from server1, and connects them to the server2, so that load on server1 is decreased (naturally, server2 CPU utilization increases).
Note: Both servers have the server application running in the background right from when they boot up (this is done by modifying the rc.local file).
Note: vm1.xml is just a dummy domain schema file. It is not used in the monitoring program. It's just kept to see what a domain schema XML looks like. May be removed in the future versions.
Important links: https://vpsfix.com/community/server-administration/no-etc-rc-local-file-on-ubuntu-18-04-heres-what-to-do/
https://stackoverflow.com/questions/40468370/what-does-cpu-time-represent-exactly-in-libvirt