ELB - seanremenyi/Notes_aws_developer GitHub Wiki

Elastic Load Balancer a load balancer istributes network traffic across a group of servers

Application LB

http https Operate at layer 7 application-aware can do advanced request routing can look at http header Network LB

tcp high performance where extreme performance is required operate at layer 4, transport layer millions of request per second while ultra low latencies most expensice options Classic

can do both legacy support x-forwarded-for headers and stick sessions for layer 7 features supports layer 4 tcp as well Gateway LB

using Geneve X-Forwarded-For header: identify the originating IP address of the client connecting through a load balancer finds ipv4 address of end user app only will see ip of load balancer but maybe want to kknow where the ip is coming from (whitelisting/blacklisting/geolocation) will pass the originating ip address to the application

errors: 504 Gateway timeout:

the target (downstream server, lambda, database) could not establish a connection application is having issues Will then need to find where the application is failing to resolve