Basically, the load balancer will distribute the traffic across multiple targets/servers and it can across multiple Availability Zones.
It monitors the health of all your targets and only spreads the load to the healthy targets, so it basically does health checks as well.
ELB is a managed Load Balancer by AWS, so AWS takes care of most of the stuff; you can also create your own but it's much more effort to maintain and integrate.
There are 3 main types of Load Balancers: 1. Application Load Balancer - Functions at the application layer (the 7th of the OSI model), so for HTTP and HTTPS. 2. Network Load Balancer - Functions at the transport layer (the 4th of the OSI model), so for high performance, TCP and UDP connections 3. Classic Load Balancer - It can only be used with EC2 classic instances. It is slowly retiring and won't be asked about in the test.
Last updated