Elastic Load Balancer

Definition:

• Load balancer
• can set sticky session (session affinity) for ALB and NLB
  • based on cookies
  • Account-based cookies: custom vs application
  • duration-based cookies: generated by lb
• Cross-zone load balancing: distribute accross multiple AZ. wb region?
• SNI: server name indication: load multiple SSL certificates to server for multiple websites
  • e.g. 1 lb has 2 certificates. SNI choose the right one to resolve
  • only for ALB and NBA, Amazon Cloudfront

Application Load Balancer

• Layer 7
• to HTTP applications across machines
  • supports websocket
• suppor routing based on path, hostname, query string
• can port map to redirect to dynamic port in ecs
• good for container-based workload
• target group: ec2, lambda, ecs task, private ip,.
• clientip can be seen in X-forwarded-port and proto header
• Crosszone: enable by default

Network LB:

• layer 4
• forward TCP/UDP traffic
• high performance, route millions of rq/s
• has 1 ip per az and support elastic ip
• supports health check
• target group: ec2, private ip, application LB (use for define layer 7 rules)
• Crosszone: enable cost extra

Gateway LB:

• layer 3
• Manage fleet of 3rd party network virtual applicance in aws
• allow traffic to be inspected by 3rd party security target group then load balanced
• Crosszone: enable cost extra