Load balancers are used to improve application performance and we also can make our application high availability:
- ELB is highly available and highly scalable load balancing service from AWS.
- AWS maintains redundant copies of ELB, if any AZ fails it automatically failovers to the ELB in different AZ.
- ELB is a region specific i.e it can load balance instance present in same region.
- ELB supports both external and internal
- ELB does health checks on instance and routes traffic to health instances, if it finds any instance unhealth that instance is taken out of rotation. If ELB finds unhealth instances are healthy, it brings them automatically into rotation.
- ELB supports SSL termination.
- ELB can be secured using security groups
- ELB types:
- A. Classic load balancer (legacy load balancer)
- B. Application load balancer (deisgined for microservices and dockers)
- C. Network Load balancer