AWS autoscaling and load balancing

Question

For my application, I use autoscaling without using elastic load balancing, is there a performance problem for using autoscaling directly without ELB?

Answer 1

Auto-scaling determines based on some measurements (CPU utilization is a common measurement), regardless of whether to increase or decrease the number of running instances.

Load balancing is related to how you distribute traffic to your instances based on a search for a domain name, etc. Somewhere you should know which IP addresses are the ones that are currently assigned to the instances that autoscaling creates.

You can have multiple IP address entries for A entries in the DNS settings, and the machines will be distributed approximately circularly from this pool. But maintaining the current pool in real time is difficult.

The load balancer gives you a simple mechanism for providing a single interface / IP address to the outside world, and he knows in what cases it is real-time load balancing.

If you use autoscaling, if you are not going to create a rather complex system for monitoring and updating DNS, you can reasonably assume that you should also use a load balancer.

Answer 2

Adi, David is right. Auto-scaling allows you to scale instances (based on cloud metrics, a single event, or a repeating graph).

Suppose you have three instances (scaled using Autoscaling): how will the traffic reach them? You need to somehow implement load balancing, so using elastic load balancing is so useful.

Without this, your traffic can only be directed to a poorly designed method.

See Slide No. 5 of this presentation on a slide show for an overview of architecture: http://www.slideshare.net/harishganesan/scale-new-business-peaks-with-auto-scaling

Best