How Do You Manage Scaling Down / Up Your Back end Servers?

I have an application with 2 backend servers(512Mb droplet) which is normally idle except for 4AM to 4PM UTC. The load is getting higher each day as the user continue to increase.

I am thinking to automatically boot another droplets from an image if the certain threshold is met and kill those droplets and leave X droplets by default if the traffic is back to normal again to save $$.

I’m using nginx as load balancer… As an example below the upstream backend IPs are hardcoded in my load balancer config. I am planning to update this config after each droplet is booted up and ready then restart nginx.

upstream backend  {
  server web-sms01:80 
  server web-sms02:80 ;
}

Do you guys have better way of doing this? My method is a bit funny I think. :)

• Resizing a droplet is not an option because 1 minute downtime is very long for my users.
• AWS ELB is not an option for now… :)