AWS Elastic Load Balancer
Distributes incoming traffic across multiple targets, such as
Must have at least 2 AZ’s to make use of it.
Sticky sessions X-forwarded-For (XFF) header
With regard to ELB health checks, when an instance is considered unhealthy, ELB doesn’t terminate it, it merely redirects the traffic to healthy instances.
Cross Zone load balancing - only available for ALB & CLB.
- I wonder, why doesn’t it work for network load balancer?
ELB’s cannot go cross region. one per region
ALB is good for web applications
NLB is good for high throughput, eg video games
3 Types of load balancer
- Application Load Balancer (HTTP(s)). Params you can apply rules on:
- host header
- source ID
- http headers
- http header method
- query string
- Network Load Balancer (TCP/UDP)
- Classic Load balancer - this bad boy’s considered legacy now.