1. Load balancing 개요

• Load balancers are servers that forward internet traffic to multiple servers (EC2 Instances) downstream.

2. Load Balancer 사용 목적

• Spread load across multiple downstream instances
• Expose a single point of access (DNS) to your application
• Seamlessly handle failures of downstream instances
• Provide SSL termination (HTTPS) for your websites
• High availability across zones

3. Elastic Load Balancer 사용 목적

• An ELB(Elastic Load Balancer) is a managed load balancer
  • AWS guarantees that it will be working
  • AWS takes care of upgrades, maintenance, high availability
  • AWS provides only a few configuration knobs
• It costs less to setup your own load balancer but it will be a lot more effort on your end (maintenance, integrations)
• 3 kinds of load balancers offered by AWS:
  • Application Load Balancer (HTTP / HTTPS only) - Layer 7
  • Network Load Balancer (ultra-high performance, allows for TCP) - Layer 4
  • Gateway Load Balancer - Layer 3